3. Hardware Flashcards

Question

Define opcode

Answer 1

– part of a machine code instruction that identifies what action the CPU has to perform

Answer 2

part of a machine code instruction that identifies what data is to be used

Answer 3

the complete set of machine code instructions used a particular microprocessor

Answer 4

a combination of hardware and software designed to carry out a specific set of functions

Answer 5

a series of dark and light lines of varying thickness used to represent data; the code has to be scanned using laser or LED light source

Answer 6

the field that uniquely identifies a record in a file

Answer 7

a matrix of dark and light squares which represent data

Answer 8

a type of QR code that includes a space for advertising

Answer 9

device that converts digital data into electric currents that can drive motors, actuators and relays

Answer 10

a device that converts analogue data (for example, data read from sensors) into a form understood by a computer

Answer 11

a light sensitive cell made up of millions of tiny sensors acting as photodiodes

Answer 12

an onscreen keyboard which uses the features of the touch screen to emulate a physical keyboard

Answer 13

a screen that allows the user to select or manipulate a screen image using the touch of a finger or stylus; touch screens most frequently use capacitive, infra- red or resistive technology

Answer 14

pain felt in the muscles, nerves and tendons caused by a repetitive action (for example, excessive clicking of a mouse button over a period of time)

Answer 15

a pointing device that uses a red LED to track the movement of the device and then relays its coordinates to a computer

Answer 16

an input device that allows the user to control the movement of an onscreen cursor or to allow onscreen selection by clicking a button on the device

Answer 17

a chip that generates an electric current (or pulses) when light falls on its surface

Answer 18

a processor that calculates, for example, the coordinates of a pointing device based on the pulses of electricity received

Answer 19

technology that can convert hard copy text or images into a digital format to be stored in a computer memory

Answer 20

software used to create drawings

Answer 21

technology that can create a 3D image of a solid object by slicing up the object into thin layers (tomography)

Answer 22

a type of touch screen that uses the change in the screen’s capacitance (the ability to store an electrical charge) when it is touched by a finger or stylus

Answer 23

a type of touch screen that uses infra-red beams and sensors to detect where the screen has been touched

Answer 24

a type of touch screen that uses two conductive layers which make contact where the screen has been touched

Answer 25

an output device that converts electrical energy into mechanical movement

Answer 26

a chip that uses millions of tiny mirrors on its surface to create a video display

Answer 27

inkjet printer technology whereby tiny resistors create heat and form an ink bubble which is ejected onto paper in an inkjet printer

Answer 28

a crystal located in an ink reservoir within an inkjet printer; the crystal vibrates and forces ink out onto paper

Answer 29

a 3D printing technique in which the print head moves in the x, y and z directions

Answer 30

IP address

Answer 31

MAC address

Answer 32

Carries signals to synchronise the fetch-execute cycle Directs the CPU Can be unidirectional or bidirectional

Answer 33

Carries data that is being processed - Bidirectional

Answer 34

Carries address locations of next item to be fetched - Unidirectional

Answer 35

MDR MAR PC CIR ACC

Answer 36

Programs / instructions are stored in memory Data is stored in memory Instructions are fetched and executed one after another

Answer 37

Holds the address … - … of next / current instruction

Answer 38

Increments to point to the address of the next instruction to be fetched

Answer 39

It holds the result of a calculation, It is located in the Arithmetic Logic Unit (ALU)

Answer 40

Temporary storage between the central processing unit (CPU) and primary memory

Answer 41

− Carries out calculations − Carries out logical operations − Holds temporary / interim values during calculations − …in a register called the accumulator (ACC)

Answer 42

Inkjet printer Laser printer 3D printer Speaker Projector

Answer 43

Scanner Microphone Keyboard Sensor Barcode reader

Answer 44

Made up of many layers of glass that act like a capacitor, creating electric fields between the glass plates in layers. When the top glass layer is touched, the electric current changes, and the coordinates where the screen was touched is determined by a microprocessor

Answer 45

Medium cost technology Screen visibility is good even in strong sunlight Multi-touch capacity Very durable screen

Answer 46

Only the use of bare fingers is permitted - Special stylus is allowed

Answer 47

Uses glass as the screen material - Needs a warm object as an input

Answer 48

Allows multi-touch capacity Good screen durability Optical system allows bare fingers, gloved fingers or a stylus for input

Answer 49

Heat-sensitive system only allows the use of bare fingers for input Very expensive Good screen visibility in strong sunlight

Answer 50

Uses glass as the screen material Sensors form a grid The location of the touch is calculated using the coordinates in the grid

Answer 51

Sensors are located on the edge of the screen Electric field all over the screen When the finger touches the screen, the charge is transferred to the finger Coordinates of the touch is calculated

Answer 52

Top layer: polyester Bottom layer: glass When the polyester layer is touched, the top layer and the bottom layer complete a circuit Signals are interpreted by a microprocessor, the calculations determine the coordinates of where the screen was touched.

Answer 53

Cheap - Can input with bare fingers, gloved fingers, or a stylus

Answer 54

Bad screen visibility in sunlight Does not permit multi-touch capability Bad screen durability

Answer 55

Data is stored in printer buffer Uses liquid ink cartridges Uses thermal bubble Rollers used to move the paper Uses a moving print head Sprays ink onto the paper Different colour inks are mixed to create required colors

Answer 56

Uses dry powder ink/toner Data stored in printer buffer Uses charged print drum Uses static electric charges Toner is fused to the paper Positive charge is replaced by negative charge

Answer 57

Uses resin Solid is built up in thin layers Uses a moving print head

Answer 58

Quick Response

Answer 59

Laser shone on QR code Black squares reflect different light to white squares Pattern is converted from analogue to digital by an ADC The data is sent to a microprocessor There is a database of valid QR codes The data is compared to stored values If data matches, entry is allowed If data does not match, entry is no allowed

Answer 60

Shines light at the barcode and light is reflected back The black bars in the barcode reflect less light than the white bars Sensors read the data The pattern is converted from analogue to digital data by the ADC Microprocessor interprets data

Answer 61

Can check stock levels Can check if there is stock in a different location When new stock items arrive, the stock levels are automatically updated in the database Can check price

Answer 62

RAM (Random access memory) and ROM (Read-only memory)

Answer 63

SSD (Solid-state drive) and HDD (Hard disk drive)

Answer 64

Non-volatile Cannot be changed Used to store the start-up instructions when the computer is first switched on

Answer 65

Volatile Used to store data and files Can be changed Never runs out of memory, it just gets slower and slower

Answer 66

Very slow compared to RAM Large number of head movement needed Expensive to change technology

Answer 67

Cheaper for large amounts of data - Greater longevity for read/write functions

Answer 68

More reliable Light Portable Lower power consumption Faster than HDD

Answer 69

USB flash drive

Answer 70

Musical Instrument Digital Interface

Answer 71

− Musical Instrument Digital Interface (file) − Stores a set of commands/instructions (for how the sound should be played) − Does not store the actual sounds − Data in the file has been recorded using digital instruments // produced by synthesizer − Specifies pitch of the note // specifies the note to be played − Specifies when each note plays and stops playing // Specifies key on/off − Specifies duration of the note − Specifies volume of the note − Specifies the tempo − Specifies the type of instrument − Individual notes can be edited

Answer 72

− MP3 is a format for digital audio − MP3 is an actual recording of the sound − MP3 is a (lossy) compression format − Recorded using a microphone

Answer 73

Lossy compression format

Answer 74

No, it is a tube filled with alcohol or mercury that can be read by a human eye in comparison to a scale, computers cannot see the level so it needs something else.

Answer 75

Temperature sensor

Answer 76

Input decives that can read or measure physical properties from their surroundings.

Answer 77

Real data is anologue in nature, meaning that there are infinite no of values and the data requires interpretation/best judgemnent from user Computers cannot make sense of real data Thermometer

Answer 78

An Anologue Digital Converter Takes real life data/physical quantities and converts them to digital format/discrete digital values.

Answer 79

Digital to anologue converter When a computer is used to control devices eg.valve Actuators are used

Answer 80

A device thatelps achieve physical movements by converting energy to mechanical force

Answer 81

When the output readings of a sensor are recieved by the microproccessor and may impact the next input to bring the system within the desired parimetres.

Answer 82

Monitoring and control

Answer 83

If the new data recieved is outside the acceptable range,a warning message/alarm appears The microprocessor/computer has no effect on what is being monitored, they simply observe and notify Pollution in river

Answer 84

If the new data recieved is outside the acceptable range, the computer/microprocessor sends signals to control aspects of the system/device. Output from the system affects the next set of inputs (feedback loop) Chemical process control(maitnaining pH)

Answer 85

Anti-lock braking systems

Answer 86

CU-control unit ALU- arithmetic and logic unit Registers and buses

Answer 87

Central processing unit Responsible for execution/processing of all instructions and data in s computer Often installed as an integrated circuit on a microchip

Answer 88

Developed a stored program computer in the 1940’s Concept of CPU CPU could access RAM directly Memory could store programs and data Stored programs were made up of data in sequential order

Answer 89

ALU-arithmetic and logic unit CU-control unit Registers

Answer 90

Allows arithmetic, logic and or operations to be carried out whilst a program is being run There can be more than one ALU to carry out specific functions

Answer 91

Reads instruction from memory/controls flow of infor Address of location where instruction is found is stored in the PC (program counter) Generates command signals along control bus System clock is used to produce timing signals for^(without system would crash)

Answer 92

Fetch-decode-execute cycle

Answer 93

In the RAM/IAS(immediate access store) The CPU takes data and programs held in a backing store and temporarily puts them into RAM This leads to faster operations

Answer 94

General or special purpose eg. ACC-actuator(carries out ALU+temporarily stores data) PC-program counter(stores address where next instruction is found) MAR-memory access register(stores address of memory currently being read/written from)

Answer 95

OR )> AND |) NOT |>º NOR )>º NAND |)º XOR ) )> XNOR ) )>º

Answer 96

Truth tables are compiled in numerical order OR: A OFF , B OFF = 0 A OFF , B ON = 1 A ON , B OFF = 1 A ON , B ON = 1 AND: A OFF , B OFF = 0 A OFF , B ON = 0 A ON , B OFF = 0 A ON , B ON = 1 NOT: A OFF = 1 A ON = 0 NOR: A OFF , B OFF = 1 A OFF , B ON = 0 A ON , B OFF = 0 A ON , B ON = 0 NAND: A OFF , B OFF = 1 A OFF , B ON = 1 A ON , B OFF = 1 A ON , B ON = 0 XOR: A OFF , B OFF = 0 A OFF , B ON = 1 A ON , B OFF = 1 A ON , B ON = 0

Answer 97

Writing a logic statement, steps: X (or other) = final logic gate in the middle brackets on either side of gate in the middle logic gate in middle of either bracket for both sides and continue working backwards

Answer 98

From information or logic statement, work from middle gate and place last and continue working from middle till done.

Answer 99

Stored program concept (Von Neumann Architecture) single processor in computer system processor uses sequential fetch-execute cycle data (files) and instructions (software) both stored in same memory (RAM) Prior to this if a computer wanted to carry out another task it would have to be physically rewired

Answer 100

Main stages of the processor’s cycle Fetch - the instruction Decode - the instruction Execute - the instruction

Answer 101

Memory Unit: temporary storage areas for data and instructions inside the processor (not within RAM) Arithmetic-Logic Unit (ALU): carries out mathematical equations on data evaluates relational comparisons inside the ALU is a general-purpose register called the accumulator (data needs to be placed in the accumulator for calculations to be carried out by the ALU) Control unit: co-ordinates what and where data goes when it enters or leaves the processor it also controls the interactions between the different parts of the processor (e.g. the registers) IAS/Immediate Access Memory (Cache memory): A processor also has built-in cache memory. This is super-fast memory (much faster than RAM) that is stored within the processor.

Answer 102

Refer to IG Computer Science OneNote for answer OneNote > Content Library > Unit 3 > Parts of a Processor

Answer 103

A temporary memory location within the processor. Registers store data and instructions whilst they are being processed. Registers are also used to move data and instructions into and around the different parts of the CPU.

Answer 104

MAR - memory address register Contains the location in RAM of the current instruction being processed MDR - memory data register Contains the contents (values, instruction) returned from RAM CIR - current instruction register Contains a copy of the contents of the MDR Responsible for decoding the instruction PC - program counter The location (memory address) in RAM of the next instruction to be fetched

Answer 105

ACC (accumulator) - stored in ALU Keeps track of data that needs to be accessed over a period of time during processing

Answer 106

Buses are wires used to transmit data within the processor and on the motherboard. Three types of buses: Address bus - used by PC and MAR to transmit locations in RAM (i.e. addresses) Control bus - used by the PC and the MDR to send instructions Data Bus - used to carry data between RAM and the MDR, and between the MDR and the CIR

Answer 107

Fetch execute cycle steps PC has address of next instruction PC copied to the MAR Lookup MAR and get contents. Copy contents into the MDR Copy MDR contents into the CIR PC is then incremented by 1 The instruction is decoded and then executed Repeat

Answer 108

An input device digitised by a scanning device such as flatbed or barcode scanner. How a 2D scanner works: Scanner shines a light beam onto document. Scanner detects level of reflected light from positions on the document. Light intensity is converted by software for each pixel position into a combination of 0s and 1s by sensing different intensities of light and dark from the document. How a flatbed works: Place document - raise cover, put document on panel and close Very bright light - (xenon lamp) Scan head - moves across the document and image is created and sent to a lens using mirrors Charge Couple Device - focused image falls on CDD, IC’s etched into silicon and software produces digital image OCR Optical character recognition: OCR alongside 2D scanner used in airport for passport to face identification eg. Distance between the eyes Width of the nose Shape of the cheek bones Length of the jaw line Shape of the eyebrows

Answer 109

Linear Barcodes are 1D and the most commonly used Steps: Infra-red laser light shines onto linear barcode. Light reflected back into the moving mirrors/prism The barcode reader’s charge-coupled device (CCD) measures the amount of reflected light input. Light measurement is converted into an electrical charge (1 or 0). Data from the bar code is sent to the computer’s processor in binary form.

Answer 110

Quick response codes are faster to read and have a greater storage capacity than UPC linear barcodes. Scanned digitally by phone’s image sensor then interpreted by microprocessor.

Answer 111

Keyboard works using plungers at the bottom of each key which when pressed pushes 2 electrical contains completing a circuit (key matrix). Key matrix (circuits) stored in ROM

Answer 112

Trackerball Mouse: - Similar to the concept of the original mouse but upside down. The movement of the ball in the socket contains sensors. The data from the sensors processed by a software determines the movement of the pointer. Optical Mouse: - A red LED bounces light off the surface onto a CMOS sensor which sends each image to the DSP for processing. The DSP detects if the mouse has moved, at what distance and at what speed.

Answer 113

All microphones need to input a varying pressure wave and then convert this to an electrical reading. Sound vibration hits a diaphragm. Movement of the diaphragm causes a coil to move. Movement of the coil induces a current through the electromagnetic effect. The electrical current is digitised (ADC - analogue-digital converter) The digital content is played back using software.

Answer 114

Light: Light Sensors are photoelectric devices that convert light energy (photons) into an electrical (electrons) signal eg. barcode scanner, automatic lights as it gets dark Temperature: A temperature sensor is a device, typically, a thermocouple or RTD, that provides for temperature measurement through an electrical signal. eg. thermometer Pressure: A Pressure sensor measures the amount of force exerted. eg. old-style electric doors, pressure inside gas canisters

Answer 115

General or special purpose eg. ACC-actuator(carries out ALU+temporarily stores data) PC-program counter(stores address where next instruction is found) MAR-memory access register(stores address of memory currently being read/written from)

Answer 116

All computers must use Primary storage and it is directly accessible by the processor because it is connected directly to the motherboard. - RAM random access memory RAM is volatile and directly connected to the CPU.

Answer 117

RAM stores data and instructions that are currently open and running. If a file or program is not open, it will not be in RAM. RAM contains parts of the operating system that are currently in use. Contents stored in RAM are directly accessible to the processor. When you load a stored file it is first loaded into RAM before any changes made to the file are processed by the CPU. RAM is volatile so when power to the computer system is lost so are the contents of RAM. Storage capacity is in GB and has read and write ability. Its contents change every time we use a computer.

Answer 118

ROM stores your computer system’s BIOS and bootstrap loader. Basic Input Output System (BIOS) Most do not need to access the BIOS on a regular basis, if at all. The BIOS allows us to change things like the bootable drive. Bootstrap loader When you first turn on (‘boot’) your computer, the operating system has not yet loaded. Your computer performs a self check of its hardware. It makes sure that it recognises it has RAM and a bootable drive of some sort. ROM is non-volatile memory between 4-8 MB storage

Answer 119

Magnetic/Solid state/ off-line A laptop or desk top computer either has an (HDD) or an (SSD) as its main secondary memory/storage device. Secondary storage devices are not directly accessed via the processor. Their contents are first be loaded into RAM before being transferred to the CPU for processing.

Answer 120

An HDD platter is magnetic the film stores data (bits) bits are written to using the magnetic read/write head the positive or negative charge (polarity) is different for a 1 and 0

Answer 121

SSDs are non-volatile storage devices No moving parts Uses flashing light to store data on chips Solid state external device Large storage capacity

Answer 122

HDD: cheaper longer lifespan larger storage capacity SDD: uses less power skinny compact no delay when reading or writing data less heat produced quieter more durable (harder to break)

Answer 123

Magnetic: Magnetic tape Floppy discs/drives HDD Optical: CDs DVDs Blu-ray DVD-RAM Solid state: SSDs USB Flash memory/memory sticks SD cards

Answer 124

Offline storage is external to the computer system and can be taken away from the computer. Magnetic: - external HDD Optical: CD DVD Blu-ray Solid state: external SSD memory stick (not USB on it’s own) SD cards

Answer 125

Data is stored on the CD on a single spiral track in pits (0s) and lands (1s). The CD drive spins the CD at a constant speed. A red laser shines on the CD’s surface. Light is reflected from the disc from the pits and lands, which is how binary data is read from the CD.

Answer 126

Primary Storage: RAM - volatile, ROM - non-volatile RAM - currently running programs and files, ROM - BIOS and bootstrap loader (start-up instructions) Internal placement RAM - plugged onto motherboard ROM - soldered onto motherboard Faster than secondary storage Directly accessible by the processor (CPU) Data and instructions must be in RAM before being sent to the CPU for processing CPU loads the operating system when the bootstrap loader in ROM runs when the computer is turned on Secondary Storage: HDD, SSD Both are non-volatile Both - stores files and programs for long-term storage Internal and external options Inside computer case, attached to motherboard via cable Portable HDD or SSD, connected via USB port Slower than primary storage Contents are not directly accessible by the processor (CPU) Data and instructions on HDD and SSD (internal and external) is loaded into RAM first

Answer 127

DVD red laser Blu-ray blue laser and more storage

Answer 128

DVD read only and one spiral track DVD-RAM read and write (at same time too) and multiple concentric tracks

Answer 129

Flash memory: solid state transistors/logic gates faster than CD-RW because no moving parts plugs directly into computer via USB port CD-RW: optical red laser slower than flash memory requires a separate CD drive to read or write data

Answer 130

They operate by heating the ink as it flows through a set of tiny nozzles. The heating process causes a small droplet of ink to form. This is then released as a single dot which forms part of a letter or image. Either thermal uses heating element to make air bubble or piezoelectric crystal to vibrate adv. Cheap, compact, faster than dot matrix, quiet disadv. colour is slow, wet ink can smudge

Answer 131

Laser printers used the same technology as photocopiers. (Image refer to laser printer image in OneNote) Laser beam and rotating mirror used to draw image of page on drum. Image converted on drum into electrostatic charge, this attracts and holds toner. Charged paper rolls against the drum. Charge pulls the toner away from drum and onto paper. Heat fuses the toner to the paper. The electrical charge is removed from the drum and the excess toner is collected. NB - for multiple colours, multiple drums

Answer 132

Comparatively noisy and low quality but cheap to run and used when carbon copies or duplicates are needed. Useful in dirty environments such as a garage because they are very sturdy.

Answer 133

3D printers use an additive printing process, using melted layers of plastic (filament) to create 3D objects. A 3D printer builds up an object from adding more and more layers of material usually PLA.

Answer 134

A loudspeaker takes an electrical signal and translates it into physical vibrations to create sound waves. The speaker is carrying out the exact reversal of what is done by a microphone. Main components are a voice coil, diaphragm and magnetic.

Answer 135

Liquid Crystal Display (LCD) Uses light modulating properties of liquid crystals 1. The screen comprises individual red, green and blue (RGB) pixels that are organised into small blocks. 2. Each ‘block’ is made of liquid crystals (hence the name, LCD!) 3. When the electric current being sent to the block of liquid crystals changes it causes the pixels to also change by turning solid or transparent. Light-Emitting Diodes (LED) Display - Uses an array of light-emitting diodes as pixels LEDs use the same technology as LCDs to create an image LCD advantages: less power low manufacturing cost LED advantages: no added light sources needed works well in very hot or cold temps fast doesn't need an AC drive

Answer 136

(Refer to OneNote for images) Capacitive: Made up of an insulating layer of glass that is coated with transparent conductive material. When an area of the screen is touched the voltage drops there. The processor uses the change in the electrical field to calculate where the screen was touched. (refer to OneNote for image) Resistive: Made up of two separate layers, bottom glass top plastic. When touched the two layers meet and this sends a signal to the processor, which uses the coordinates of the screen to calculate where it was touched. Infra-red: Screen is made of glass and requires human input for touch, if touched in multiple places the location can’t be determined. Works with matrix of IR beams like lasers in spy movie.

Answer 137

Liquid Crystal Display (LCD) projectors: sharper/better image quality Quieter pixels are more visible uses less power and runs cooler than a DLP projector projects light through three prisms (RGB) three lights (RGB) merge when they pass through a fourth prism to display an image onto a large screen Lamp > separation prism > colour filter > combining prism > lens = image Digital Light Projectors (DLP) : lighter, more portable produces ‘blacker blacks’ often more expensive than regular LCD projectors uses a thousands of micro mirrors (built onto on integrated circuit (chip)) to project an image onto a large screen Lamp > condensing lens > colour filter > shaping lens > DMD > lens = image

Answer 138

An operating system is a collection of programs that form the basis of the main system software found in a computer system. An operating system provides a platform for application software to be installed.

Answer 139

An interrupt is an electronic signal from hardware or software that requests the processor’s attention. An operating system contains a program called an interrupt handler. The role of the interrupt handler is to prioritise the interrupt signals as it receives them and places them in a queue to be handled. Interrupts can be hard or software based, are handled by the operating system, allow a computer to multitask, does not work out priority and a computer cannot function without interrupts. ––––––––––––––––––––––––– Interrupts are signals sent to the CPU by external devices to indicate that an event needs immediate attention They tell the CPU to stop what it is currently doing and give priority to the interrupt Hardware interrupts are generated by hardware devices eg. printer out of paper Software interrupts generated by programs eg. divide by zero

Answer 140

Categories: System software, Application software System software: Programs that are needed to run the computer eg. windows Application software: Programs that are needed to perform tasks for the user Free software, freeware, shareware: Most commercial software has to be paid for Using an unlicensed copy of software is a copyright infringement and is illegal Some software is free of charge and allows users to study, modify and distribute it

Answer 141

Free software is software that comes with permission to use, copy and distribute it with modification either gratis or for a fee

Answer 142

Open source software is free of charge and the source code is given to a user to use in any way they like

Answer 143

Freeware may be used without payment it may permit redistribution but not modification as the source code is not available. Examples: Google chrome Skype Adobe reader

Answer 144

A software that is initially free on a trial basis The software is copyright and after trial must be paid for, the source code is not available and it can not be modified but is often encouraged to be made copies of and shared to help distribute it.

Answer 145

System software: Operating systems Utility programs Program translators Examples: IOS Android OS X Windows Google chrome Linux Definition and function: Software that manages a computer’s hardware and provides a user interface Also provides security

Answer 146

Without user interface we would communicate in binary Types: GUI , graphical user interface; most commonly associated Menu-driven interface; music players and ATM machines CLI, command line interface; all user commands types in as text and no graphics, uses less space on disk and RAM Voice activated Real-time Windows; WIMP - Windows, Icons, Menus and Pointers; user can click on icons using a pointer or cursor and right click to display a menu

Answer 147

Data used by the computer is copied into main memory The operating systems keeps a record of where each program and its data are located It must not overwrite pre-existing programs

Answer 148

When running multiple programs on a computer, the programs in the background running are taking turns to get processor time to execute instructions The OS Manages how the programs share the processor Task manager

Answer 149

Peripherals are all the devices outside of the CPU, input/output devices and secondary storage, access speed of these is relatively slow

Answer 150

Status of each job on a printer screen displaying whether it is printing or waiting to print

Answer 151

OS manages: Copying files from disk to main memory Copying data files back to secondary storage Hard disk in computer is a storage peripheral: OS manages where on disk files are written, keep track of their location to be fetched, making sure no file overwrites another file

Answer 152

OR )> AND |) NOT |>º NOR )>º NAND |)º XOR ) )>

Answer 153

Not- 1 input becomes 0 vice version And- Only 1 and 1 gives 1 output Or- Gives 1 when there is atleast 1 in inp Nand- Gives 1 every time except 1 and 1 Nor- Only gives 1 when input 0 and 0 Xor- Gives 1 when only 1 input is 1

Answer 154

Stores instructions, programs and data in the memory, - Instructions fetched and executed one after another one by one

Answer 155

PC holds address of next instructions Address held in PC sent to MAR via address bus MAR goes to location in memory where instruction is stored Instruction sent to MDR via data bus Instruction then sent to CIR Control unit sends signal to manage process using control bus Value in PC incremented by 1 Then instruction is decoded and executed

Answer 156

Address bus- carries signal relating to addresses between the processor and the memory; unidirectional Data bus- can transfer data between the processes and memory and I/O devices; bi-directional Control bus- carries signals relating to the control coordination of the fetch-execute cycle ; uni and bi-directional Memory unit- Uses MAR and MDR, made up of partitions. Each has an address and contents. CPU only refers to main memory Main memory- IAS, RAM, holds data/instructions currently in use. Directly accessed by CPU, Volatile memory

Answer 157

ALU - Arithmetic and Logic Unit, allows for arithmetic calculations and logic operations to be carried out ACC- Accumulator, register which acts as a temporary storage location for immediate result from the ALU and values from calculations PC- Program counter, register used by CPU to hold address of next instruction to be executed CIR- Current instruction register, holds instruction currently being executed or decoded MAR- Memory address register, holds memory location of data that needs to be accessed MDR- Memory data register, holds data content waiting to be written or read from location pointed by MAR

Answer 158

Interrupt: To identify that the processor’s attention is required To stop the current process To allow multitasking To allow for efficient processing To allow for efficient use of hardware Buffer: -Region of memory used to temporarily store data while it’s being moved from one place to another Examples of interrupts: Hardware issue, such as a printer paper jam Key press by the user, e.g. CTRL ALT DEL Software error

Answer 159

Circuit board present at base of keys When key is pressed that presses a switch When pressed the circuit is complete Location of key press is calculated Each character has an ASCII value Key press generates an interrupt

Answer 160

A light is shone on the surface of the document Light source is automatically moved across the document Reflected light captured by mirror and lenses. Used to scan sheets of paper

Answer 161

Works using laser or light source which is shone across the object The width,height,depth of object measured Model is replicated and created Used to scan patient bodies, scan an object to create copies

Answer 162

-Input device Scanned using a barcode reader − Shines (red) laser/light − Light is reflected back, white lines reflect light, black lines reflect less light − Sensors/photoelectric cells detect the light − Different reflections give different binary values − Pattern is then converted to binary values − Microprocessor interprets the data Has to be bought separately But Quicker to scan than type, less human errors

Answer 163

Illuminator/Light shone on code Black squares reflect different light to white Corner squares used for alignment Reflected light is focused on photosensitive cells or CCD Pattern converted to digital data Data sent to microprocessor

Answer 164

Output device Fixed on walls User can calibrate the device to make sure sensors align with projected image Can use finger or pen to interact Where touch is performed, location is calculated and output is shown

Answer 165

Input device Takes analogue sound and converts them into electrical signals So computer can understand and process it

Answer 166

Input device Takes analogue sound and converts them into electrical signals So computer can understand and process it

Answer 167

Light- Detect light, street lights Temperature- detects temp, ovens Pressure- detects pressure, collision Magnetism- uses earth magnetic field Humidity/Moisture- used in greenhouses Acidity- pH of water, treatment of water Motion- detects motion, burglar alarm

Answer 168

Uses static electricity Uses powdered ink Rotating drum used to transfer image on paper Has negative charge Laser removed negative charge from areas and scans Toner transfers from drum to positively charged paper -Prints high volume, cheaper cost per page, fast speed, expensive to buy, toner is expensive, has warm up time, heavy

Answer 169

Uses a moving print head Produces output using materials like plastic and resin Uses layer upon layer of material to create output Products can be customised but does have limitations to what can be made Uses piezoelectric or thermal technology -Can create prototypes easily, prosthetic arms, dangerous objects could be created

Answer 170

Sensors take reading and data is sent to microprocessor Analogue signal from sensor converted into digital using analogue to digital converter (ADC) Microprocessor compares data against pre-set values If matched no action taken If not matched microprocessor sends signal and decreases or increases value accordingly Process is continuous and repeated

Answer 171

Rollers used to move paper Nozzles sprays liquid ink onto paper Ink jet drops ink on paper Different coloured inks mixed to create ideal color May use thermal or piezoelectric tech -Prints high quality, cheap to buy, no warmup time, more expensive per per, ink could smear

Answer 172

-Design is created on the computer / software / CAD -Material is loaded to cutter -Different types of material can be used -Uses lasers to cut material that use infra-red that produces extreme heat that is focussed using a special lens -Can work on both the x, y and z axis

Answer 173

− Liquid crystal display − The display is made of pixels arranged in a matrix − Uses a flat panel display − Backlit display with CCFLs/LEDs − Uses light-modulating properties of liquid crystals − Crystals can be turned between opaque and transparent (to allow light to pass) − Colours created using RGB − Not good at low temp as crystals can become solid − Low power consumption − Runs at cool temperature − Do not suffer image burn − Do not suffer flicker issues − Bright image/colours − High resolution image − Cheaper to purchase than e.g. LED screen

Answer 174

− Light emitting diodes (technology) − The display is made up of pixels that are arranged together as a matrix − Each is formed of three LEDs/filters − Shades of colour are achieved by mixing red, blue and green − The screen can be back-lit/edge-lit − Energy efficient // low power consumption − Long lasting // longevity − Focussed beam // less light strays from beam − Brighter/vivid colours − High resolution − No flicker − Display is thinner − Mercury free technology // environmentally friendly − Fewer pixel failure − Increased viewing in sunlight

Answer 175

Screen has 2 layers Needs pressure to be applied to create a circuit, top layer is pressed Calculation carried out where layers connect and output is produced accordingly It’s cheaper but easily damaged Used in GPS, printers, digital cameras

Answer 176

Electrical field spread across the screen Sensors located around the screen When finger touches screen, the charge is transferred to the user as it is affected by conductivity of the human body Coordinates of touch determination or calculated Used in smartphones, iPads Has multi-touch capabilities Can’t be used wearing gloves

Answer 177

Operated by signals to cause a physical movement, controls the movement of a machine

Answer 178

Uses thousands of tiny mirrors that can move very quickly to create an image

Answer 179

− Uses rolling ball / optical sensor / laser to detect motion − Movement echoed on screen /moves curser (on screen) − Has scroll wheel / Buttons to allow data input

Answer 180

− Memory that is directly accessed by the CPU − An example is RAM / ROM − RAM stores programs and data that are currently in use and ROM stores boot-up instructions − RAM is volatile and ROM is non volatile − RAM typically has more storage than ROM − Volatile memory means data is lost if device is powered off, non-volatile is when data remains even after device is powered off.

Answer 181

− Storage that is not directly accessed by the CPU − An example is HDD / SSD − Stores data / files that can be accessed at a later stage − Non volatile

Answer 182

SSD better than HDD: − Faster read/write operation − Less latency − Produces less heat // needs less cooling − Less susceptible to interference/magnets − Less power consumption HDD better than SSD −Cheaper − Infinite amount of read/write cycles

Answer 183

SSD − Flash storage − Uses transistors and controls gates − Can be NAND/NOR technology − Stores data by flashing it onto the silicon chips − Controlling using the flow of electrons through transistors/chips/gates − The electric current reaches the control gate and flows through to the floating gate to be stored − When data is stored the transistor is converted from 1 to 0 / 0 to 1 − Some use EEPROM technology

Answer 184

− It has platters − Platters/disk divided into tracks − Platter/disk is spun − Has a read/write arm that moves across storage media − Read/writes data using electromagnets − Uses magnetic fields to control magnetic dots of data − Magnetic field determines binary value Benefits: − Has more longevity than solid state storage − Has more read/write cycles than solid state storage − Cheaper per unit of data − Trusted technology used for many year

Answer 185

How its read − Red laser is used, laser beam shone onto disk − Disc is rotated on a constant speed to be read − Surface is covered in track − Data is represented on the surface using pits and lands − Pits represent binary valves − Pits reflect light back differently How data is written − Laser beam is used − Laser makes indentations on the surface of the disc − Data is written in spiral track − Pits and lands represent binary values − It is non-volatile − Can be easily disconnected from the computer or inserted − It is not directly accessed by the CPU − Suitable example e.g. CD, DVD, USB flash memory − Portable, small − Expensive to buy per GB

Answer 186

Optical- CD, DVD, Blu-ray Solid state- USB flash drive (important to mention flash drive) , SD cards Magnetic- HDD

Answer 187

− DVD uses red laser/light whereas blu-ray uses blue/violet laser/light − DVD has a smaller (storage) capacity // Blu-ray has a larger (storage) capacity − DVD has two layers (of polycarbonate) whereas Blu-ray disks have a single layer (of polycarbonate) − DVD has a slower transfer rate (of approximately 10 mbps) // Blu-ray has a faster transfer rate (approximately 36 mbps)

Answer 188

Infra red rays are sent across the screen from the edges Sensors are around the edges and capture beams Infra red is broken by a finger blocking it Calculation is made to locate the touch based on where the beam was broken

Answer 189

location of a device on a network

Answer 190

number that uniquely identifies a device

Answer 191

DRAM - SRAM

Answer 192

Constructed of tiny capacitors that leak electricity Requires a recharge every few milliseconds to maintain its data Inexpensive Slower SRAM Can store many bits per chip Uses less power Generates less heat Used for main memory

Answer 193

Constructed of circuits Hold its contents as long as power is available Expensive Faster than DRAM Can store many pits per chip Uses more power Generates more heat Used for cache

Answer 194

Non-volatile memory chip Primary memory In a microprocessor holds the BIOS Can’t be written to

Answer 195

PROM (Programmable read-only memory) – It can be programmed by user. Once programmed, the data and instructions in it cannot be changed. EPROM (Erasable Programmable read only memory) – It can be reprogrammed. To erase data from it, expose it to ultra violet light. To reprogram it, erase all the previous data. EEPROM (Electrically erasable programmable read only memory) – The data can be erased by applying electric field, no need of ultra violet light. We can erase only portions of the chip.

Answer 196

NAND More expensive Faster read Erase singular byte

Answer 197

NOR chips Less expensive Slower read Erase blocks of bytes

Answer 198

Cache holds the information from the RAM that is most actively used, and accessed most frequently. The computer system will run faster as the slower main memory will need to be accessed less frequently. When the processor needs to read from the main memory, it first checks if a copy of the data exists in the cache. If the data to be read do not exist in the cache, the data are first copied to the cache and then used. When the processor needs to write to the main memory it does so through cache memory.

Answer 199

-RAM Contains instructions currently in use -ROM Contains the startup/bootstrap program -SSD Stores program data to operate the car

Answer 200

Uses platters Platters divided into tracks Platter is spun Read write arm moves over platter Magnetic fields control magnetic dots of data Magnetic field determine binary value

Answer 201

Non-volatile memory - Uses NAND flash memory

Answer 202

No moving parts (more reliable in a portable device) Use less power Smaller (good for portable devices) Faster data access Run cooler Run quieter

Answer 203

Cheaper for large amounts of data Greater longevity for read/write functions Don’t need faster speed of SSD Expensive to change technology

Answer 204

CD DVD Blu Ray

Answer 205

Uses 1 spiral Red laser used to read/write Dual layer technology

Answer 206

Uses concentric tracks - Allows read/write operations at same time

Answer 207

DVD-R one spiral track DVD-RAM several concentric tracks DVD-RAM can be written to and read at same time;DVD only allows read DVD-R only allows read; DVD-RAM allows read and write DVD-RAM can have direct access because of concentric tracks

Answer 208

Uses blue laser - Uses single1.1mm polycarbonate disc

Answer 209

Larger Capacity Blue laser rather than red laser Single polycarbonate layer not two layers

Answer 210

Greater longevity – more read and writes Speed is sufficient Cheaper per unit of data – better value No portability requirement Trusted technology

Answer 211

portable HD USB flash drive

Answer 212

loads software Manages hardware Manages error handling Manages user accounts Allows multitasking Provides an interface

Answer 213

A signal sent to the processor Requests processor time Processor stops to service interrupt Interrupts have different priorities

Answer 214

Printer Keyboard Mouse

Answer 215

Control bus Address bus Data bus

Answer 216

Carries signals Directs the CPU Can be unidirectional or bidirectional

Answer 217

Carries address locations of next item to be fetched - Data travels one way ( unidirectional)

Answer 218

Carries data that is being processed - Data travels in both directions (bi-directional)

Answer 219

PC; Program Counter MAR; Memory address register MDR; Memory data register CIR; Current instruction register ACC; Accumulator

Answer 220

Controls operation of memory, processor and input/output Fetches each instruction in turn Interprets instructions Sends signals to other components telling them what to do

Answer 221

Carries out calculations Carries out logic operations Holds values during calculations in a register called an accumulator (ACC)

Answer 222

Programs / instructions are stored in memory Data is stored in memory Instructions are fetched and executed one after another

Answer 223

A device that allows data to be entered into a system

Answer 224

A device that allows the user to see/hear data

Answer 225

PC has address of next instruction to fetch PC copied to MAR via address bus Instruction copied from memory to MDR Instruction copied from MDR to the CIR Value in PC incremented to point at next instruction to fetch Address of instruction placed in MAR Instruction decoded and executed

Answer 226

Paper placed on a glass panel Bright light illuminates the document (modern scanners use a xenon light) Scan head moves across the document Lens focuses on the document image Scanned image turned into electric form by the CCD

Answer 227

At airports to read passports - OCR software used to read text

Answer 228

CT Scanners - MRI Scanners

Answer 229

Red laser shone at barcode Light is reflected back Sensors detect the light back Pattern converted to digital Microprocessor interprets the data Each digit made up of 2 dark and 2 white lines

Answer 230

Easy to change prices on stock items No need to price every item on the shelf Allow for automatic stock control

Answer 231

Faster checkout Reduces errors Itemized bills

Answer 232

QR Code scanned by camera Light reflected back Black squares reflect less than white squares Three large squares used to define alignment Squares data is decoded – each square has a binary value Processed by an app Links to website or document QR code can be saved and used again

Answer 233

Barcode 1D QR is 2D QR code can contain more data QR code can be read from any angle QR codes faster to scan than bar codes

Answer 234

Fewer typing errors because one button is pressed to order an item Speeds up time to order because fewer buttons pressed May require less training

Answer 235

A diaphragm vibrates producing an electric signal - Signal goes to a sound card and is converted into digital values

Answer 236

Users voice converted into digital signal Spoken words produce a digital pattern Software compares wave pattern to patterns stored in memory If they match person is identified

Answer 237

Spoken words recognized and shown on screen

Answer 238

The software needs to be trained - Some dialects and accents can cause problems

Answer 239

Cars - Siri

Answer 240

Uses multiple layers of material that transmit electric current When top layer is touched into the lower layer current changes and location is found

Answer 241

Cheap to make - Can use when wearing a glove

Answer 242

Conductive layer Current flows from 4 corners – electric field created Sensors monitor field When screen is touched charge transferred to finger - current changes and location is calculated

Answer 243

Poor in sunlight Easily scratched Doesn’t allow multi touch

Answer 244

Good in sunlight Durable Allows multi touch

Answer 245

Screen can crack on impact - Can’t use while wearing gloves

Answer 246

1. Invisible grid of infra-red beams on screen 2. When screen is touched beam is broken and location is calculated

Answer 247

Durable Allows multi touch Can use with gloves

Answer 248

Expensive to make Screen can crack on impact Sensitive to dirt

Answer 249

1. Temperature Aircon, central heating 2. Motion Detects if an infra-red beam has been broken and sends a signal to the microprocessor 3. Pressure Detects a change in pressure and receives current if a circuit is created sending a signal to the microprocessor 4. pH 5. Light 6. Magnetic fields 7.Anti-lock brakes on a car

Answer 250

Burglar Alarm Street Lights ABS Brakes

Answer 251

Sensor detects input (Name the sensor) Analogue data converted to digital Signal sent to microprocessor Microprocessor compares signal to stored value If value outside range signal sent to device Actuator used to operate device Process is in a continuous loop

Answer 252

Interrupt - Signal sent to computer about no paper - Buffer – Area of memory used to temporarily store data being sent to the printer

Answer 253

Laser Inkjet 3D

Answer 254

Used for low quantities of documents Used for photographs - Uses liquid ink cartridges - Uses thermal bubble - Rollers used to move the paper - Uses a moving print head - Sprays ink onto the paper - Different colour inks are mixed to create required colours

Answer 255

Used for high volume quality output User toner cartridges Uses charged print drum Uses static electric charges Toner is fused to the paper

Answer 256

Used to make physical model from blueprint Used to create physical model from CAD Uses resin Solid is built up in thin layers Uses inkjet technology with a moving head

Answer 257

Similar to direct but uses two passes 1st pass sprays dry powder 2nd pass sprays a binder (type of glue)

Answer 258

-Very complex designs can be made as the cutters are controlled by computers

Answer 259

Sound produced by passing digital data through a digital to analogue converter (DAC) then through an amplifier Sound produced by voltage differences vibrating a cone Rate with which DAC can translate the digital signals is know as sampling rate

Answer 260

Brighter image Higher resolution Thinner screen Uses less power Last longer

Answer 261

Organic layers are thinner, lighter and more flexible OLED layers can be made from plastic so are lighter Brighter than LED No backlighting required so use less power Can be made into large thin sheets for advertising boards Very large field of view

Answer 262

Uses millions of micro mirrors on a DLP chip Micro mirrors can switch on/off thousands of times a second Bright white light passes through colour filter on its way to the DLP chip Light split into primary colours RGB

Answer 263

Older technology than DLP Beam of light generated by a bulb Light sent to group of chromatic-coated mirrors that reflect the light back at different wavelengths corresponding to RGB Three different light components pass through three LCD screens Images are then combined using a prism to create full colour image Finally image passes through projector lens onto a screen

Answer 264

a company that provides the user with access to the internet - usually with a monthly fee gives a user an account and email address

Answer 265

uniquely idenitifies a devic connected to the internet - the MAC address does not change but can be LAA or UAA

Answer 266

the software running in the background of a computer system - it manages many of the basic functions

Answer 267

a signal sent from a device (or other software) to the processor requesting its attention

Answer 268

a temporary memory area in a device

Answer 269

how a computer system is designed

Answer 270

buses move data around the computer and also send out control signals to synchronise the internal operations

Answer 271

high-speed storage areas within the computer

Answer 272

it is made up of addresses and contents

Answer 273

it controls the operation of the memory, processor and input/output devices

Answer 274

human-computer interface (HCI) multitasking multiprogramming batch processing error handling load/run applications management of user accounts file utilities processor management memory management real-time processing interrupt handling security input/output control

Answer 275

ovens washing machines

Answer 276

they carry out simple, unchanging tasks which are initiated by a user pressing a button

Answer 277

temporarily stop what it is doing and service the interrupt

Answer 278

to compensate for the slower operating speed of peripherals when compared to a processor

Answer 279

to carry on with other tasks

Answer 280

printers music/video streaming

Answer 281

a concept that holds programs and data in memory data moves between the memory unit and processor between processor, memory unit and input/output devices

Answer 282

carries signals relating to addresses between the processor and memory uni-directional

Answer 283

sends data between the processor, memory unit and the input/output devices bi-directional

Answer 284

carries signals relating to control and coordination of all activities within the computer, it can be uni-directional or bi-directional due to internal connections

Answer 285

in registers

Answer 286

Memory address register (MAR) Memory data register (MDR) Arithmetic and Logic Unit (ALU) Program counter (PC) Current Instruction Register (CIR)

Answer 287

read instructions interprets instructions sends out signals along control bus to synchronise all computer components

Answer 288

the next instructions are fetched from the memory address stored in the PC this is then stored in the CIR the PC is incremented by so the next instruction can be processed

Answer 289

the decoded instruction is then passed as a set of control signals to the appropriate components of the computer system

Answer 290

It is an abstract way of describing the structure of a system or algorithm. An input is taken, processed, and results in an output. It has the practicality to standardize inputs and outputs, leaving the process unimportant. input → process → output

Answer 291

A feedback loop is added from output to input, and storage is added to the process. The storage can be used as a cache.

Answer 292

It is a central procession unit and controls the manipulation of data. It uses data to perform operations. It includes: ALU CU Registers

Answer 293

A core is a set of CU, ALU, and registers. Some CPUs have multiple cores, which means they can process instructions much more quickly.

Answer 294

It stores the current data needed to carry out instructions.

Answer 295

It is the arithmetic logic unit, where mathematical and logical calculations are done.

Answer 296

It is the Control Unit, which controls the activities done by the CPU

Answer 297

They are quick, small stores of data within the CPU.

Answer 298

It contains three major characteristics: The Main Memory Stores Binary Values The CPU Inputs and Outputs

Answer 299

Fetch: The Address of the next instruction is copied from the PC into the MAR The PC is incremented by 1 Decode: The CU obtains the address of the current instruction from the MAR via the RAM The RAM returns the data to the MDR via the data bus Execute: The data from the MDR is copied into the CIR and decoded by the ALU which results are stored in the ACC

Answer 300

Memory Data Register Memory Address Register Program Counter Current Instruction Register Accumulator

Answer 301

The MAR stores the address of the current data that the processor requires.

Answer 302

The number of cores The Cache Size The Clock Speed

Answer 303

The Program Counter stores the address of the next instruction, and it increments once the address is copied into the MAR.

Answer 304

The accumulator stores mathematical and logic results being transferred from or to the memory unit.

Answer 305

The Current Instruction Register contains the current instruction which is being carried out.

Answer 306

The clock provides timing signals to synchronize the circuits. CPUs are designed to operate at their respective clock speeds, the faster the clock speed the faster the CPU. The faster the clock speed, the faster the fetch-execute-decode cycle.

Answer 307

The Clock Speed refers to the amount of electrical pulses that the clock inside the CPU can produce every second.

Answer 308

It is what is directly accessible by the CPU and includes RAM, ROM, and Cache.

Answer 309

It is memory directly accessible by the CPU, which includes RAM, ROM, and Cache - although predominantly it refers to the RAM.

Answer 310

Volatile and Non-Volatile. Volatile Memory is temporary and lost when power is, whilst Non-Volatile memory retains data when power is lost. Memory is normally Volatile, besides ROM. Storage is Non-Volatile

Answer 311

Random Access Memory is RAM. Ram has quick read/write times. It loads open programs and operating system data currently in use. Essentially it stores the data of what is currently being used.

Answer 312

Read-only memory is Non-Volatile, and can only be read and cannot be changed. It contains essential programs, like the programs used to boot the computer.

Answer 313

It is Volatile, and stores copies of frequently used data. CPU Cache sits between the CPU and RAM and is checked before RAM in the fetch phase. Because it stores commonly used data, it is placed much closer to the CPU, although browsers and storage may also have caches.

Answer 314

It is a temporary memory, it is a memory management procedure used when the RAM is full. It is created from secondary storage that is temporarily converted into volatile memory. Data from non-current processes are sent as pages from the RAM to the Virtual Memory, and it is much slower.

Answer 315

It is Non-Volatile, a part of SSD (Solid-State Memory; non-mechanical). It is more reliable and durable, but can only be overwritten a finite amount of times.

Answer 316

Buses carry data around the computer, the names are representative of the data they carry. They are a collection of wires through which data is transmitted, and they are: Data Bus Address Bus Control Bus (Instructions)

Answer 317

CPU → Address Bus → RAM (UniDirectional) CPU ←→ Data Bus ←→ RAM (Bidirectional) CPU ←→ Control Bus ←→ RAM (Bidirectional)

Answer 318

It is storage not directly connected to the CPU and is Non-Volatile.

Answer 319

Portability Durability Reliability Cost Capacity Speed

Answer 320

It is storage stored through pits and lands. Data is written via laser to burn pits through the disks, light is then shone on the disks in which the reflection of light is used to read data. It includes: CD DVD Blu-Ray

Answer 321

Advantages: Good Portability Can be Rewritten Disadvantages: Small Capacity Easily Damaged

Answer 322

Magnetic Storage uses read/write heads that contain electromagnets. Parts of the disc are magnetized (1) or demagnetized (0) - and the heads read this.

Answer 323

It is a form of flash memory, so it is non-mechanical. Electrons are stored in transistors and capacitors, in which data is stored. When it is connected to power, these electrons ‘flash’ into the device.

Answer 324

Advantages: Cheaper Larger Storage Disadvantages: Easily Broken Noisy and generates heat

Answer 325

Advantages: Much Faster Reliable because non-mechanical silent portable don’t produce heat Disadvantages: Expensive Degrades over multiple read-write cycles

Answer 326

Cloud Storage is data stored on multiple servers, in remote locations. Servers use magnetic/solid-state storage. It operates through a web-based API.

Answer 327

Advantages: Easily Accessible anywhere with an internet connection Can share files with other people easily Disadvantages: If no internet, no access Must trust Provider Can be expensive

Answer 328

They are special-purpose computers that perform very specific tasks and aren’t easily programmed. They include: Dishwashers Heating Systems Microwaves Calculators

Answer 329

Logic Statements can be evaluated as either true or false.

Answer 330

A Truth Table is a method of representing every possible output based off on the inputs to a Boolean Expression.

Answer 331

AND NOT OR NAND NOR

Answer 332

Not Reverses an Input. Ā = B 1 → 0 0 → 1

Answer 333

An or gate returns true if either conditions are true, aka if a 1 is present. A V B = C / A + B = Q 1 & 1 → 1 1 & 0 → 1 0 & 0 → 0

Answer 334

AND gates are the opposite of OR gates, it returns true if both values are true. 1 & 0 → 0 0 & 0 → 0 1 & 1 → 1

Answer 335

The user places the document face down on the glass Light moves across document Reflected light is captured Uses mirrors and lenses Captured image is converted into a digital file Produces a 2D digital image

Answer 336

Scanners shines a laser (or light) over the surface of a 3D object Records measurements of the geometry/dimensions of the object Measurements are converted to digital file Produces a 3D digital model this could be used in CAD

Answer 337

Shines light / (red) laser at barcode Light is called an illuminator Light is reflected back White lines reflect light Black lines reflect less light/absorbs light Sensors / photoelectric cells detect the light Different reflections / bars will give different binary values pattern converted to digital values A microprocessor interprets the data

Answer 338

barcode identifies a (unique) product barcode can be used to look up product (in a database) data about stock levels can be stored on a system stock can be automatically deducted from the system can check stock is below a certain level // check stock level automatic re-order automatically update new stock level to locate if an item of stock is available in another location

Answer 339

To management: much easier and faster to change prices on stock items no need to price every stock item on the shelves (this reduces time and cost to the management) allows for automatic stock control possible to check customer buying habits more easily by linking barcodes to loyalty cards. To customers less errors faster checkout

Answer 340

quick response code scans the QR code with the mobile device Black squares reflect light different to white Corner squares are used for alignment App is used to read/interpret/decode the QR code converts to digital data links to a website/opens a document can store the QR code to refer to again for the information

Answer 341

barcode 1D and QR code 2D barcodes contain vertical lines and QR codes contain ‘squares’ QR code can hold more data than a barcode QR code can be read from any angle, some barcode readers have to be lined up with the barcode QR codes are faster to scan than barcodes barcodes are frequently used at checkouts while QR codes are used for advertising

Answer 342

The camera will break up what it sees through its lens into a grid of pixels Each pixel is given a binary value – Pixels form a grid (to create the image) Each pixel has a color Pixels are stored in sequence (in a file) A shutter will open letting light onto a CCD sensor that is at the back of the lens This information is interpreted as digital information and stored in the cameras memory.

Answer 343

circuit board present at base of keys A key is pressed that presses a switch When a key is pressed it changes the current in a circuit The location of the keypress is calculated An index of characters is searched to find the corresponding keypress

Answer 344

Converts sound into an electrical signal/voltage used for voice recognition systems used for computer interpreting words being said

Answer 345

allows a user to write on a surface using a pen, the text and drawings can then be captured and stored for later use.

Answer 346

resistive touchscreens capacitive touchscreens infrared touchscreens

Answer 347

Screen has two / multiple layers User presses on top layer Top layer connects to bottom layer creating a circuit Calculation is carried out on where layers are connected signals interpreted by microprocessor to determine location

Answer 348

is made up up of layers of glass current sent/flows out from all 4 corners of the screen sensors are used to read the electric field when finger/stylus touches screen, charge transferred to user and current changes the location of “touch” is calculated

Answer 349

an “invisible” grid on the screen sensors detect where the screen has been touched through a break in an infrared beam(s) − the position where the screen touched is calculated needs a warm object to carry out operations heat sensitive

Answer 350

This touch screen can be used whilst wearing gloves doesnt have multi touch capabilities it is cheaper than others visibility in sunlight poor screen wears out/scratches

Answer 351

has quick response time good visibility in sunlight This touch screen has multi-touch capabilities screen (glass) will shatter/break/crack (on impact) (very) durable surface This touch screen cannot be used whilst wearing gloves

Answer 352

A sensor is a hardware device that will take measurement of physical properties like temperature, pressure or acidity.

Answer 353

Gas Infra-red Light Temperature Pressure Moisture / Humidity Acoustic PH Magnetic Field

Answer 354

Suitable sensor (motion/infra-red) Data converted (from analogue) to digital (using ADC) Data sent to microprocessor Data is compared to stored value/range if data matches/out of range action taken nothing could happen Continuous loop/process

Answer 355

Rollers are used to move the paper through the printer Nozzles spray ink onto the paper print head are moved across the paper (to distribute the ink) Different colour inks are mixed to create required colours Technology could be piezoelectric Technology could be thermal bubble Ink is heated evaporates into a bubble Electrical current is applied to a crystal which forces a drop of ink through nozzle

Answer 356

data sent from computer to printer The printer driver ensures that the data is in a format that the printer can understand printer driver ensures printer is ready to print Data is then sent to the printer and stored temporarily in the printer buffer then whichever printer it is carries on process

Answer 357

inkjet uses liquid ink/ laser uses powdered ink and toner cartridge inkjet uses thermal bubble and piezoelectric technology while laser printer uses a charged printing drum inkjet sprays ink in droplets on the paper while laser printer makes use of static electricity charges inkjet uses a moving print head while laser printer does not use a moving printing head inkjet is suitable for low volume (high quality) output while laser printer is suitable for high volume and quality output e.g a photo/ e.g leaflets

Answer 358

makes use of toner/powder ink uses (positive and negative) charged drums // rotating drum uses static charge no moving head faster at printing high volume output/high speed producing flyers/leaflets/magazine

Answer 359

This is an output device that creates an object by building layer upon layer of material by additive manufacturing Produces output using materials such as plastic and resin uses prototype from CAD to create physical model

Answer 360

Uses a high powered laser to create the output Creates 3D prototypes Outputs a physical 3D product

Answer 361

reaches maximum brightness quickly colours are vivid good colour definition/contrast can be achieved screens can be thinner/thin more reliable as LED’s are long lasting consume very little/less energy

Answer 362

It is a flat panel display It creates images using red, green and blue diodes It is also used in mobile devices such as smartphones and tablets

Answer 363

has 6 layers Glass/plastic top layer Cathode layer Emissive layer Conductive layer Anode Glass/plastic bottom layer

Answer 364

Memory that is directly accessed by the CPU An example is RAM / ROM RAM stores programs and data that are currently in use and ROM stores boot-up instructions RAM is volatile and ROM is non volatile Faster than secondary storage Is internal to computer

Answer 365

non-volatile storage that isn't directly accessed by CPU Stores data / files that can be accessed at a later stage An example is HDD / SSD internal to the computer has a slower access speed

Answer 366

Non-volatile storage Off-line storage is storage that is removable from a computer/device/ portable An example of off-line storage would be CD/DVD/USB stick/SD card Used to store files as a backup

Answer 367

random access memory stores instructions currently in use It is volatile It is temporary Has a larger capacity than ROM Data can be read and written from (edited)

Answer 368

DRAM ‐ needs to be constantly refreshed to retain the data; it uses millions of transistors and capacitors. SRAM ‐ doesn’t need to be constantly refreshed to retain its data; it uses flip flops.

Answer 369

read only memory stores boot instructions / BIOS It is non-volatile It is permanent Hs lower capacity than RAM Data can only be read from

Answer 370

Hard disk drive stores files / applications Most common method to stored data on pc It uses magnetic properties to store data It has moving parts It is non-volatile storage

Answer 371

It is cheap Can store large amounts of data Relatively fast write speed Great longevity

Answer 372

solid state drive Stores files/ applications It has no moving parts It is non-volatile storage It uses flash memory to store data It has a limited number of read/write cycles Sometimes uses EEPROM technology Uses NAND chips When data is stored the transistor is converted from 1 to 0

Answer 373

More durable (no moving parts) Very fast (no moving parts) Faster start up time (No Latency) Less noise less heat Smaller portable

Answer 374

compact disc Optical storage device Single layer Red laser used to read data Single track Data stored in pits and bumps Smallest storage capacity

Answer 375

Digital Versatile Disc Optical storage device Dual layering Red laser used to read data Stores data in spiral track Single track

Answer 376

uses concentric tracks allows for editing greater longetivity

Answer 377

optical storage device Dual layering Read using blue laser Concentric track Largest storage capacity

Answer 378

Differences in HDD AND SSD * HDD has moving parts but SSD does not * HDD uses magnetic storage whereas SSD uses flash memory * HDD is slower to access data than SSD * HDD will create noise/heat, whereas SSD runs quieter/cooler * HDD has higher power consumption than SSD * HDD have more read-write cycles whereas SDD has limited number of read-write cycles * HDD larger in physical size/heavier than SSD * HDD is normally cheaper for the same capacity of storage as SSD * HDD is available in a larger storage capacity than SSD

Answer 379

Solid state storage optical media storage magnetic storage

Answer 380

It stores data electronically and does not have any moving parts. It is made of silicon chips. It uses less power and produces less heat. It can be found in three types i.e. drives, cards, and modules. The transfer of data is much faster because of no mechanical parts.

Answer 381

laser is used (Laser beams) shines onto surface of the disk It is rotated (at a constant speed) to be read Data is represented on the surface using pits and lands Pits and lands represent binary values Pits reflect light back differently (to the area in between/land) Optical device can determine the binary value from the light reflection

Answer 382

Storage device has platters Platters/disk divided into tracks Storage platter / disk is spun Has a read/write arm that moves across storage media Read/writes data using electromagnets Uses magnetic fields to control magnetic dots of data Magnetic field determines binary value its cheap with high longevity

Answer 383

Uses solid state storage Connect directly to computer through usb port Small and lightweight NAND chips are used

Answer 384

Any storage directly accessed by the CPU RAM, ROM and Registers/Cache

Answer 385

It’s much faster to access data from PS than SS

Answer 386

Volatile - All data lost when computer turns off The computer’s working memory Can be written to, and read from

Answer 387

Non-volatile - data permanently on disk Used for computer’s start-up instructions (Bootstrap) Read-only - can’t be changed

Answer 388

Needed for longer term storage of data because it is non-volatile. External devices are also portable and can have large capacities

Answer 389

Require little power and generate little heat Lack of moving parts, therefore small, reliable and portable Much faster than hard disks, and don’t require cooling equipment

Answer 390

Cheaper than SSDs

Answer 391

Short/medium term storage of music/video Can last 10-25 years

Answer 392

Microscopic transistors act as control gates and floating gates to control the flow of the current Current flowing = 1 No current = 0 Use NAND or NOR gates

Answer 393

A laser reflects light off the surface of a disk with a spiral track of lands and pits When the laser hits the the curved start/end of a pit, the light is refracted and a 1 is recorded When light is reflected either from the land or pit, a 0 is recorded

Answer 394

Hard disks are magnetic surfaces divided into tracks and sectors They rotate around a spindle and a read/write head is moved onto the correct track Particles on the magnetic disk are polarised (north = 0, south = 1) The read/write head must be parked once operation is finished, otherwise it will break

Answer 395

When there isn’t enough space in RAM for all of the programs and data that are being used

Answer 396

Small section of hard drive reserved to act like RAM When program in VM is needed, it is swapped with something in RAM This could cause your computer to slow down as it is a further distance to get to hard drive than to RAM

Answer 397

Remote file storage on someone else’s servers. Often done with major third-party companies.

Answer 398

Physical devices are still needed to store data in cloud storage

Answer 399

No need to purchase local storage devices Files are automatically backed up without user input Remote access to your files from any Internet connected device, anywhere in the world Enables easier file-sharing/collaboration More environmentally friendly (One cloud storage server > millions of individual servers

Answer 400

May need to commit to annual subscription Backup/restoring could be slower than local storage Security of the data will be managed by a third party (outside of user’s control) Need an Internet connection to access data

Answer 401

Network security has improved, so users more comfortable with risks assosicated with cloud storage Large capacity data storage costs have improved 4G and 5G networks have enbaled much faster browsing/download speeds to access data

Answer 402

A computer whose programs and data it uses is stored in the same memory

Answer 403

An instruction is brought from the RAM. It is then decoded by the CU to find out what to do with the instruction The instruction is then carried out

Answer 404

To continuously process instructions and data that are inputted by repeatedly carrying-out the FE cycle

Answer 405

Carries out the mathematical and logical operations (e.g. AND, OR, NOT) and compares values held in registers

Answer 406

Coordinates all of the CPU’s actions in the FE cycle Decodes all instructions Sends and receives control signals to fetch and write data

Answer 407

It regulates the speed and timing of all signals and computer functions

Answer 408

PC MAR MDR ACC CIR

Answer 409

They are very small, fast memory locations that temporarily store memory addresses, instructions and data

Answer 410

Holds the instruction currently being executed

Answer 411

Holds data or a program instruction after it is stored/fetched from memory

Answer 412

Where the ALU stores its results (from its operations)

Answer 413

Holds the memory address of the next instruction to be executed

Answer 414

The memory address held in the PC is copied into the MAR The PC is incremented. It now holds the address of the next instruction The processor sends a signal across the address bus to the memory address held in the MAR The instruction/data held in that memory address is sent along the data bus to the MDR The instruction/data in the MDR is copied into the CIR The instruction/date held in the CIR is decoded and then executed (results held in ACC) The process repeats

Answer 415

Clock speed Cache size Number of cores

Answer 416

One tick of the clock counts as one FE cycle. So the faster the clock, the more ticks there are, the more FE cycles there are

Answer 417

A CPU can contain multiple cores, with each core processing one operation per clock cycle A dual/quad-core can perform two/four operations simultaneously therefore more clock cycles

Answer 418

If the software used is only written for one core, additional cores may be redundant

Answer 419

It is a small amount of very fast memory that can be accessed faster than RAM RAM is further away from the processor than cache

Answer 420

Makes the CPU more efficient as less time is spent waiting for data to be transferred

Answer 421

1) 2 x 3.2 GHz = 6.4 GHz + 4MB 2) 2 x 2.7 = 5.4GHz + 4MB 3) 1 x 3.2 GHZ = 3.2GHZ + 2MB 4) 4 x 1.5GHZ = 6GHz + 8MB Therefore 1 is fastest But 4 is slightly slower with more cache/cores so it could be faster

Answer 422

Used to control the function of electronic devices that don’t need a full OS since they perform specific tasks. Their input is also frequently controlled by a switch/button

Answer 423

Air conditioning, microwaves, vending machines, lighting systems

Answer 424

Hardware required to be able to access any network Can be wireless or use an Ethernet cable to connect

Answer 425

A unique, hexadecimal, static ID number assigned to every NIC used in network devices Static = It does not change

Answer 426

12 character (6 byte) hexadecimal address e.g. 30-A5-BD-6F-CF-63

Answer 427

Makes up the unique manufacturer code 30-A5-BD-6F-CF-63

Answer 428

Makes up the unique serial code of that specific device 30-A5-BD-6F-CF-63

Answer 429

A static or dynamic address allocated to each device. It can be assigned by a router Internet Protocol

Answer 430

A device for connecting network-connected devices together to form a network They collect knowledge of available routes to transmit data and then determine the most suitable route for sending data.

Answer 431

Between local networks and the Internet to join them together with the public IP address from the Internet and the private IP address from the local network

Answer 432

Assigns the IP address for your network Internet Service Provider?

Answer 433

Any device that allows you to pass information from the outside world into a computer system

Answer 434

It shines a red laser at a barcode to illuminate it. White lines reflect the light back, whereas the black lines absorb the light The strength of reflection is interpreted by a microprocessor and then converted into a binary value

Answer 435

Scanning goods at checkouts Checking library books in and out Tracking packages out for delivery

Answer 436

Faster checkout queues Reduces errors caused by manual input More detailed tracking informaiton Automatic stock control

Answer 437

Light enters the camera and falls onto a sensor Each pixel in the sensor measures the light intensity A microprocessor converts these values into digital data that represents colour values

Answer 438

Integrated into most smartphones Proffesional photography Security and surveillance systems

Answer 439

Largely replaced traditional, film-based cameras Instant photographs (i.e. no development needed) Digital photos can easily be transmitted via WiFi, Bluetooth etc Embedded software can adjust photos

Answer 440

Each character on a keyboard has a corresponding character set value Key presses are converted into a digital signal; this is what the computer interprets

Answer 441

Built into laptops Connected to most desktop computers via USB/wireless Tablets and smartphones use virtual keyboards

Answer 442

One of the most common forms of text-based data input

Answer 443

Vibrations caused by sound waves cause a coil to move around a magnet, resulting in electrical field changes These changes are converted by a microprocessor and an ADC into a digital representation of the sound

Answer 444

Music recordings Dictation Radio, TV and films Online communication

Answer 445

Captures any real-world sound and stores it as a digital approximation Digital sounds can be modified

Answer 446

Uses a red LED and a sensor to determine the movement of the mouse relative to the surface beneath A microprocessor analyses both the speed and distance of the movement and it replicates this on-screen via a virtual cursor

Answer 447

Navigation and interaction with almost all elements of a graphical user interface (GUI)

Answer 448

Easy interaction with applications and other GUI elements More reliable as there are no moving parts, unlike mechanical mice No need for a special surface (i.e. mouse mat)

Answer 449

Reads using a camera (usually from a mobile device) An app processes the image and converts the squares into readable data

Answer 450

Advertising products Quick links to websites so don’t need to type in a URL Sharing contact details instantly

Answer 451

Holds far more information than a traditional barcode Barcode holds: 30 digits QR code holds: 4296 characters (7089 digits)

Answer 452

Consists of two conductive layers The two layers are separated by an insulating layer (gap/inert gas) When the screen is pressed, the two layers contact and complete the circuit

Answer 453

Cheap to produce Can be activated with any object (gloved finger, stylus etc) Very resistant to surface contaminants

Answer 454

Lower image clarity and precision compared to other types

Answer 455

LEDs shine infrared light across a screen, forming a matrix When the screen is touched the beams are interrupted

Answer 456

Composed of a protective layer, transparent conductive layer, glass substrate Touching the screen with a barefinger/stylus changes the electrostatic field of the conductive layer

Answer 457

Cash machines Information kiosks Medical equipment

Answer 458

Tablets Laptops Smartphones

Answer 459

Excellent image clarity Very high precision Durable screen Allows for multiple touches at the same time

Answer 460

Requires a bare finger or capacitive stylus for activation

Answer 461

LEDs shine infrared light across a screen, forming a matrix When the screen is touched the beams are interrupted

Answer 462

Very large-scale commercial displays Information kiosks Medical equipment

Answer 463

Excellent image quality Unlimited touch-life Scales very well

Answer 464

Sensitive to interference from ambient light, water, snow etc.

Answer 465

They shine a bright line across a document to measure the levels of reflected light and create a digital version of it

Answer 466

Creating digital versions of documents and photographs Reading passports at airports Photocopiers

Answer 467

A simple, cheap and effective way of generating a digital representation of 2D objects for further manipulation

Answer 468

They shine a laser over the surface of an object to record its geometry and dimensions and create a digital model of it

Answer 469

Creating 3D models for use with CAD software Dentistry Product development Quality inspection Research

Answer 470

A simple, cheap and effective way of generating a digital representation of 3D objects for further manipulation

Answer 471

It carries out physical movements

Answer 472

Opening and closing an automatic door Turning a wheel Operating an aircraft’s wing flaps

Answer 473

Used with sensors to control many kinds of mechanisms Translates digital signals into movement of physical objects

Answer 474

Digital Light Processing projector

Answer 475

It is a matrix of millions of micro-mirrors on a small microchip White light is shone through a rotating colour filter to produce an image

Answer 476

Projecting a computer output onto a wall/whiteboard

Answer 477

Higher contrast and definition Smoother video quality Smaller, lighter and more portable

Answer 478

Three mirror filters separate an image into red, blue and green wavelengths The three images are then combined to produce one full-colour image

Answer 479

Projecting a computer output onto a wall/whiteboard

Answer 480

Cheaper Quieter Less power and heat output

Answer 481

Tiny droplets of ink are forced through a fine nozzle onto a sheet of paper

Answer 482

Small-scale print jobs High-quality professional photos

Answer 483

They are small and compact They are excellent for high-quality colour photos

Answer 484

Paper can be damp/wrinkle after printing

Answer 485

The printer generates a mirror image of the printed page and draws the image onto a drum using a laser (creates negative charged areas) Toner (powdered, positively electrostatic ink) is attracted to the drum The toner is transferred to the paper and bonded using a heat roller

Answer 486

Fast and accurate for black and white documents Lower running costs per page

Answer 487

Colour printers and toner cartridges are expensive

Answer 488

A digital signal is sent through a DAC (digital to analogue converter) and then passed on to a speaker to create sound

Answer 489

It deposits laters of materials on top of each other to slowly build a 3D object

Answer 490

Inexpensive prosthetics Spare parts Rapid prototyping

Answer 491

Allows us to produce real-world models of virtual objects created using CAD software Can be used to design products that are more easily repairable

Answer 492

Devices which are used to input data and instructions into a computer. Input devices allow us to enter raw data into a computer. The computer processes the data and then produces outputs that we can understand using an output device. Input devices can be manual or automatic.

Answer 493

Mechanically scans illuminated surface of paper document with a single row of hundreds of light sensors Scanner computer digitises analogue signals, processes and sends to computer Flatbed scanner – paper document places on glass ‘platen’. Saved as image OCR software can convert images into text data which can be edited by a word processor May be used in offices to scan documents

Answer 494

Advantages: Flat-bed scanners are very accurate and can produce images with a far higher resolution than a digital camera Disadvantages: Can produce very large image files which need a lot of computer memory to view and edit

Answer 495

A 3D scanner is a device that analyses a real-world object or environment to collect data on its shape and possibly its appearance (i.e. colour). The collected data can then be used to construct digital three-dimensional models. Contact scanners probe object Non-contact scanners use light or radiation, detects reflection or radiation passed through objects May be used by architects to scan scale models of projects

Answer 496

Advantages: industrial computed tomography scanning can be used to construct digital 3D models, applying non-destructive testing Disadvantages: many limitations in the kind of objects that can be digitized optical technologies encounter many difficulties with shiny, mirroring or transparent objects

Answer 497

Barcodes consist of short parallel lines in contrasting colours and different thicknesses Reflected laser light detects differences in lines Combination of scanner hardware & software Processor and decoding software in scanner ID codes used to look up description & price in database Used for identification of items Commonly used in shops to scan items or airports to scan boarding passes

Answer 498

Advantages: saves time (automatic inventory) are efficient in recording information durable Disadvantages: cannot read damaged or obscured barcodes

Answer 499

Grid of light sensors that pick up optical image Computer scans analogue signal, digitises data and displays on monitor screen When user presses shutter button, shutter opens to let in light Stores data as image file in memory

Answer 500

Advantages: No cost to purchase and process film Display acts as viewfinder No processing delay: can view and delete immediately Easier and quicker to edit Easily sent over network Disadvantages: Uses a lot of power Small handheld digital cameras cannot store many photos. A corrupted memory card may result in lost photos. Cost - top specification digital cameras can be far more expensive than their equivalent roll film cameras

Answer 501

A user enters values and commands into a computer by pressing keys on a keyboard A standard keyboard each key has a value printed on it Users of English usually type on a QWERTY keyboard, named from the first 6 letters on the first row A concept keyboard consists of rectangular grid of keys. A flat overlay sheet covers the keyboard. It has a suitable picture, symbol or word for each key. Often used in restaurants. A numeric keyboard: A rectangular block of keys with the numerals 0 to 9. Can be used for inputting PINs when we pay by credit card, on mobile phones, or on keyboards next to the QWERTY layout.

Answer 502

Advantages: simple, familiar, reliable technology (typewriters used the same QWERTY layout) Disadvantages: It is slower as human operator takes more time in thinking and typing. Only one letter can be typed at a time. Slow compared with devices for automatic data capture. Prone to vandalism in public locations

Answer 503

Allows user to point by moving a cursor User selects items by clicking switch buttons on mouse A mechanical mouse has a small ball underneath that can roll over a flat surface. The mouse detects and converts the rotations of the ball in two dimensions into digital signals. An optical mouse has no moving parts, detects movement by changes in reflected light Used with a graphical user interface (GUI)

Answer 504

Advantages: Fast method on inputting commands, feels natural Moves the cursor faster than the arrow keys of keyboard Disadvantages: Needs flat surface on which to operate, can be easily vandalised Hard to use by people with physical disabilities Not always suitable to carry around, especially with PCs Picks up dust and dirt easily - ball may become stuck Textual data can’t be input

Answer 505

Screen is sensitive to the touch of a finger or stylus Three types of systems to recognize touch: resistive, capacitive, and surface acoustic wave Resistive system consists of glass panel covered with a conductive and a resistive metallic layer. When the user touches the screen and the layers make contact the electric current running through the layers changes. The change in the electric field is used to calculate where the screen was touched. Capacitive system has a layer storing electrical charge placed on monitor’s glass panel. Charge is transferred to user’s finger, and the charge decrease is detected and used to calculate where the screen was touched. Surface acoustic wave system consists of two transducers (one receiving, one sending) placed along the x & y axes of the monitor’s glass panel, along with reflectors to reflect an electrical signal sent between the transducers. The receiving transducer can tell if the signal was disturbed by touch. Used in phones, portable gaming consoles, Point-Of-Sale terminals, tourist information kiosks and systems to find out about public transport.

Answer 506

Advantages: Difficult to vandalize Don’t need separate keyboards or mice which can be stolen Can be made reasonably weatherproof Users need no previous computer knowledge to be able to use them, feels intuitive Less prone to malfunction due to dust and dirt Combines output device (screen) with input device so reduced space requirements Makes use of finger gestures, such as pinch to zoom Disadvantages: People with disabilities may find them difficult to use Not suitable for inputing large amounts of data Long periods of usage can be tiring Generally more expensive

Answer 507

Converts sound vibrations into an analogue signal. Usually connect the microphone’s signal to the computers sound card with a cable Diaphragm in microphone vibrates with sound. This may move a magnet or coil that induces current to flow in the wire. Used in phones, webcams, and laptops for adding sound to a multimedia presentation, mixing music and video conferencing

Answer 508

Advantages: Voice recognition software can be used to convert your voice into text or to control menu options on a phone system Disadvantages: Stored audio files can take up a lot of memory Voice commands can be difficult to recognise by the software

Answer 509

A sensor is a device that produces an electrical signal in response to a stimulus. Detects or measures a physical property and usually sends the data to a computer which can then record, indicate, or otherwise respond to it Can collect data more frequently, accurately and reliably than a person Can collect data from places unsafe for humans, e.g. lava flows, nuclear reaction vessels

Answer 510

Produces a signal that depends on the level of light falling on it. Can be used as an input to an automated system that controls a device’s level of light output, e.g. the brightness of headlights, streetlights, or screens.

Answer 511

Produces a signal that depends on the temperature of its surroundings. The computer processes the digitized signal to display a measurement or to control an appliance. Used in electronic thermometers or thermometers in controlling heating systems in buildings including greenhouses and chemical reaction vessels.

Answer 512

Produces a signal depending on the magnetic field surrounding it Can detect changes and disturbances in a magnetic field like flux, strength and direction. Rotation, angles, direction, presence and electrical current can all be monitored. Magnetic sensors are divided into two groups, those that measure the complete magnetic field and those that measure vector components of the field. The vector components are the individual points of the magnetic field. The techniques used to create these sensors involve various combinations of physics and electronics. Can be used to detect the earth’s magnetic field, or smaller magnetic fields Used for compassing in cell phones and handheld GPS receivers, as well as in vehicles. Also used in industrial processes and scientific measuring

Answer 513

Produces a signal depending on the concentration of a particular gas or vapour Used in breathalysers, environmental monitoring and chemical process control

Answer 514

Produces a signal depending on the pressure to which it is exposed Used in blood pressure monitors, chemical reaction vessels and robots

Answer 515

Produces a signal depending on how wet it its surroundings are Used in irrigation systems to measure water ocncentration in soil

Answer 516

Produces a signal depending on the concentration of water vapour in the atmosphere Can be used in greenhouses, for controlling heating, ventilating and air conditioning systems, or for recording information for weather records

Answer 517

The pH meter has a rod-like probe, usually made of glass, with a bulb at the bottom which contains the sensor. The probe produces different voltages at different pH levels; theoretically producing 0 volts at pH 7 (neutral), negative voltages at acid pH levels and positive voltages at alkaline pH levels. Used in chemical and pharmaceutical manufacturing, as well as in schools for lab experiments

Answer 518

Produces signal depending on the level of infrared radiation falling on it Infrared radiation may be detected by temperature differences (using the thermoelectric effect), pyroelectricity (where materials are able to generate a temporary voltage depending on temperature), or changes in resistance. A change in an area’s infrared radiation is detected as movement. Used in alarm systems, remote controls, weather monitors and sensor-operated traffic lights.

Answer 519

An output device is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system (such as a computer) which converts the electronically generated information into human-readable form Taken from Wikipedia LAWL

Answer 520

Uses a printhead to propel droplets of ink from fine nozzles onto paper Printhead passes left and right across paper while roller feeds paper forwards

Answer 521

Advantages: Good colour production (good for printing pictures) Low purchase cost Disadvantages: Ink is expensive Water-soluble ink smudged when damp Slow output rate

Answer 522

Uses a laser scanning a drum to print with powdered ink, called toner Printer paces an even, negatively static charge on a photoconductive drum Laser beam scanned on the rotating drum causes negative charge to leak away Drum revolves past negatively charged toner supply which is attracted to the regions on the drum where no charge remains

Answer 523

Advantages: High resolution and rate of output - useful when printing multiple copies of one sheet as the same pattern of negative charge is used Toner is not water-soluble, so does not get smudged when wet Toner is cheaper than inkjet printer ink Disadvantages: Expensive to buy Toner is toxic Colour production not as precise as inkjet printers

Answer 524

Makes a three-dimensional solid object of any shape from a digital model. Some 3D printers use inkjet technology. Others use lasers to fuse granules of plastic, metals, ceramic or glass. It can also be done by successive layers of material being laid down in different shapes. Construction of a model can take anywhere from several hours to several days, depending on the method used and the size and complexity of the model.

Answer 525

Advantages: Can produce a wide variety of manufactured products, including customisable products and personal designs Rapid prototyping Fast manufacturing of printed products Even though the initial setup costs are higher, 3D printing is becoming cheaper than cheap labour in third world countries More Jobs: engineers to design and build 3D printers, technicians to maintain, use, and fix 3D printers Potential in medicine to print customisable human body parts or organs Disadvantages: Currently, 3D printers only manufacture products out of plastic, resin, certain metals, and ceramics. Printing of copyrighted products to create counterfeit items will become more common and nearly impossible to determine. Easy to print dangerous items such as guns or knives Currently, 3D printers are limited with the size of the products that they can create

Answer 526

Use laser to cut precise patterns in most materials Approx. 20mm limit for depth of the cut Used in industry, for example to cut a sheet of metal

Answer 527

Advantages: Quick way to cut through many different materials Disadvantages: The laser cutter can only cut on a single flat face and does not recognize the other faces of an object like a 3D cutter

Answer 528

A three-dimensional laser cutter is like a regular laser cutter, except the laser is able to recognize all sides of a shape and not just the shape’s face. Can be used to make models of objects

Answer 529

Advantages: Can cut many different types of materials, such as glass, crystal, metal and wood. Can be set to cut the inside of the material, allowing more complex shapes Disadvantages: Ordinary 3D cutters using a rastering motion do not allow for 3D shapes of the sort that have ledges or require undercutting, or any kind of cutting/machining that can’t be done from vertically above and perpendicular to the X-Y plane.

Answer 530

An electromagnet causes a diaphragm to vibrate depending on the electrical current. The diaphragm’s vibrations causes the air to vibrate, which produces sound Headphones and earphones are small versions of speakers designed to fit on or in your ear, used to prevent other people from hearing private content

Answer 531

An output device used for controlling a system, though it does not always provide output directly to the user Usually paired with sensors that provide feedback to the control program Actuators can act to affect the real-world depending on the signal or reading received

Answer 532

Very thin display screens Small, light and easy to fit on a table or mount on a wall The screens are backlit to make it easier to read Different types include: Liquid Crystal Display (LCD) Light-Emitting Diodes (LED)

Answer 533

Uses two sheets of material with a liquid crystal solution between them Monitor’s control program scans and sends signals to individual liquid crystal pixels to allow certain amounts of light and colour to pass through Used in some types of digital watches and PCs

Answer 534

Advantages: Sharp images Zero geometric distortion at the original resolution of the screen Bright images - best for brightly lit environments. Consume little electricity and produce little heat Immune to screen image burn-in Disadvantages: The colour and contrast from various viewing angles is inconsistent Poor colour production of black and very dark grays - not suitable in darker environments Motion blur is common With brightness from backlighting, imagery may appear flat Pixel-based display may be stuck on screen Fixed resolution Newer technology costs more

Answer 535

Stands for Light Emitting Diode A diode that glows when voltage is applied as the result of moving electrons Allows the flow of current in a single direction only Typically used outdoors in store signs, billboards or information screens

Answer 536

Advantages: LEDs are much smaller than LCD fluorescent lamps so the screen itself can be made thinner and lighter — good for mobile phones LEDs are high-efficiency light sources, and low power consumption leads to significant energy savings Switch on rapidly, even when cold Disadvantages: The colour of white LEDs can be very inconsistent

Answer 537

An LCD projector is a video projector used to display images, videos and computer data on a screen or other flat surface LCD projectors send light through a prism that separates light into three panels, red, green and blue components of the video signal The images stack on each other on the screen to produce the image Used in home theatres, school classrooms, etc.

Answer 538

Advantages: Can achieve greater brightness at a lower energy consumption Sharp image Possible to achieve greater zoom magnification with an LCD projector Disadvantages: Because there are three panels, it is possible for one to fall out of alignment. This will cause one of the three stacked images to be shifted slightly. Filters need to be cleaned periodically, causing an LCD projector to be more maintenance intensive

Answer 539

Stands for Digital Light Processor. Uses a digital micromirror device, where microscopically small mirrors are laid out to create the image. In a single chip DLP projector, colours are produced either by placing a colour wheel between a white lamp and the DLP chip or by using individual light sources to produce the primary colours, e.g. LEDs or lasers. A three-chip DLP projector uses a prism to split light from the lamp, and each primary colour of light is then directed to its own DLP chip, then recombined and directed out through the lens. Used in some cinema systems and large venue projectors.

Answer 540

Advantages: Unlike LCD projectors, DLP screens do not rely on fluids and are therefore not limited in size by their inherent mirror mechanisms, making them ideal for increasingly larger high-definition theatre and venue screens. Disadvantages: May use more electricity, and generate more heat, than competing technologies. People may be bothered by the “rainbow effect”, particularly in older models.

Answer 541

1 → 0 0 → 1

Answer 542

0 & 0 → 0 1 & 0 → 0 0 & 0 → 0 1 & 1 → 1

Answer 543

0 & 0 → 0 0 & 1 → 1 1 & 0 → 1 1 & 1 → 1

Answer 544

0 & 0 → 1 0 & 1 → 1 1 & 0 → 1 1 & 1 → 0

Answer 545

0 & 0 → 1 0 & 1 → 0 1 & 0 → 0 1 & 1 → 0

Answer 546

0 & 0 → 0 0 & 1 → 1 1 & 0 → 1 1 & 1 → 0

Answer 547

0 & 0 → 1 0 & 1 → 0 1 & 0 → 0 1 & 1 → 1

Answer 548

XOR gate (with two inputs)?

Answer 549

Computer data storage refers to computer components and recording media that retain digital data used for computing for some interval of time. Computer data storage provides one of the core functions of the modern computer, that of information retention. It is one of the fundamental components of all modern computers.

Answer 550

Directly connected to and accessed by a computer’s CPU Typically volatile memory (except ROM), meaning it can only retain data as long as there is power provided Used for processing data Data on primary storage is accessed about a million times faster than data on secondary storage Typically smaller than secondary storage Examples: Read Only Memory (ROM), Random Access Memory (RAM) and DVD-RAM

Answer 551

Indirectly accessed, typically by a cable Non-volatile memory, meaning data is retained when the computer is turned off Used for storing long-term data Data accessed slower than on primary storage, as it must first be copied into the primary storage in order to be used Typically larger than primary storage Examples: Hard Disk Drive (HDD) and Solid State Drives (SSDs)

Answer 552

Removable from computer Cannot be accessed without human interaction (physically inserting/removing the device) Used to transport data Can be used to backup data Can increase security when stored in a remote location, therefore not vulnerable to computer-based attacks (e.g. viruses) Examples: Digital Versatile Disks (DVDs), Compact Disks (CDs), Blu-ray, USB flash memory and removable disks

Answer 553

processor can only use data or software in the memory memory is not large enough to store all the data and software required by user RAM is lost when computer is turned off and ROM cannot be changed, so there is nowhere in the memory for data to be stored long term and be changeable. backing storage (auxiliary storage) stores programs and data for future use data in backing storage is usually changeable and non-volatile access to backing storage is slower than access to internal memory, as data needs to be copied into the memory in order to be used

Answer 554

The storage device is the machine that reads/writes the data; the storage medium is the material on which the device stores data.

Answer 555

Data held magnetically on a medium that moves past a read/write head Tiny areas magnetised in different ways to store bits Data read by detecting the presence of a change or the absence of a possible change in magnetisation between successive regions If the device can read the medium then it can turn it back into codes for the computer Examples: hard disk drive (HDD), magnetic tape

Answer 556

Held on surface by ‘pits’ burnt by a laser Laser shined on pits. The differences can be used to store the code Media can be read by a shining less intensive laser and detecting the intensity of light reflected from successive regions Examples: CDs, DVDs, Blu-ray

Answer 557

Like internal memory, it is electronic and made as integrated circuits or chips No moving parts (makes it robust) Fits directly into the computer The device and the medium are the same thing Examples: solid-state drives (SSDs), USB flash memory, flash memory disks

Answer 558

The structure of a computer system - the hardware components it has and how they work together to execute programs

Answer 559

Input & output mechanisms Main memory Central processing unit (CPU)

Answer 560

Program instructions Data

Answer 561

To decode and execute program instructions fetched from memory

Answer 562

A task that is carried out by the CPU

Answer 563

Instructions and data are stored in main memory Instructions and data are fetched, decoded, and executed in a sequence by the CPU

Answer 564

Program instructions and data are stored in main memory and are fetched by the CPU one at a time, where they are decoded and executed Results of operations carried out in the CPU are stored in memory

Answer 565

Computers could be reprogrammed to carry out different tasks because they were able to store program instructions and data in memory

Answer 566

Input - Keyboard Mouse Scanner QR code reader Sensor Microphone Touchscreen / tablet Output - Monitor Printer Projector Speaker Touchscreen / tablet

Answer 567

It holds the program instructions and data that the CPU is currently using It consists of a collection of storage locations, each with its own unique address (a storage location can hold a program instruction or an item of data)

Answer 568

A pointer to a location in memory

Answer 569

Power is needed to retain its contents When the computer is switched off, its main memory is completely wiped

Answer 570

The CPU has fast, direct access to it

Answer 571

The storage locations can be read from and written to in any order

Answer 572

Stores currently executing programs and data Volatile - if a computer loses power, all data stored in its RAM is lost Not suitable for long-term storage of software/data Contents of RAM can be manipulated while computer running

Answer 573

Memory that cannot be changed by program or user Retains its memory after computer turned off - its contents are permanently embedded Used to store instructions/software for the computer to boot up when turned on - e.g. BIOS

Answer 574

Cache memory stores commonly used instructions and is used to speed up processing Cache located on same microchip as CPU, so can be accessed much quicker than ordinary RAM Executing a program from cache memory means it runs more quickly Computers don’t have much cache memory because it is much more expensive

Answer 575

It’s an area on a secondary storage device used to store programs if you do not have enough physical memory to store them Programs that are open but not currently active are transferred to virtual memory to make room in main memory Not physical

Answer 576

Physical, secondary storage devices Non-volatile storage Solid state technology, so non-mechanical More reliable and durable than alternatives - can only be overwritten limited number of times

Answer 577

Handles all processor signals Controls flow of data within the system Fetches instructions from memory sequentially, decodes them and directs operations of other parts of the system to execute them

Answer 578

Performs arithmetic and logic operations on data

Answer 579

Controls the rate at which program instructions are executed Each ‘tick’ of the clock triggers the CPU to carry out one action Its speed is measured in cycles per second: 1Hz = 1 cycle per second (Modern CPUs have clock speeds of around 3GHz)

Answer 580

Direct-access storage which temporarily stores data and instructions within the CPU

Answer 581

Any two from: Program counter / PC Current instruction register / CIR Memory address register / MAR Memory data register / MDR Accumulator / ACC

Answer 582

Holds the memory address of the next instruction to be fetched from main memory Memory address incremented during the fetch process

Answer 583

Holds the instruction currently being executed or decoded

Answer 584

Holds the memory address of current data that is to be fetched from memory

Answer 585

Holds data found at memory address held in MAR, or data that is to be transferred to main memory

Answer 586

Holds the result of a calculation performed by the ALU

Answer 587

A processing unit within the CPU, containing an ALU, control unit and registers

Answer 588

A collection of wires that is used to transfer data between the CPU, main memory and input/output devices

Answer 589

Control bus Address bus Data bus

Answer 590

Carries signals from the processor between the components of the CPU and other parts of the computer system (bidirectional)

Answer 591

Holds the address of the memory location that the CPU will read from or write to (unidirectional)

Answer 592

Transfers program instructions and data between memory and the CPU (bidirectional)

Answer 593

Each memory location has a unique binary address Each wire in the address bus represents one bit of the address Therefore, the number of wires it has determines how many unique addresses can be generated

Answer 594

The CPU needs to be able to read program instructions and data from memory and write the results of operations to memory

Answer 595

Instructions are fetched from memory into the CPU one at a time, where they are decoded and executed by the control unit (CU) Arithmetic and logic operations are performed by the ALU

Answer 596

Fetch - Memory address of current instruction held in program counter is copied into MAR Address in program counter is then incremented by one - program counter now holds address of next instruction Processor sends signal containing memory address of current instruction along address bus to main memory RAM retrieves instruction/data stored at that address and passes it back along the data bus to MDR - instruction is then copied into CIR Decode - Control unit (CU) reads contents of CIR, checking if it is a part of its instruction set Execute - Instruction held in CIR is then decoded and executed by CU - the results of processing are stored in ACC

Answer 597

Any one from: Software allows instructions to be passed to the hardware so that it can carry out tasks Software is the set of instructions that controls the hardware

Answer 598

Clock speed Number of processor cores Size of cache Type of cache

Answer 599

Any one from: More instructions can be carried out per second Processes run faster Programs executed faster

Answer 600

Any one from: The CPU/computer could overheat More cooling required Needs more power

Answer 601

Any one from: Cache stores frequently used data so the processor does not have to wait because cache is checked before main memory / because RAM is further away from the processor It speeds up processing because cache is a faster type of memory

Answer 602

Level 1 (L1) cache - extremely fast, usually embedded in the CPU, closest to the processor Level 2 (L2) cache - slower than L1 cache, one stage further from the processor, may be located on CPU or separate chip Level 3 (L3) cache - specialised memory that works to improve performance of L1 and L2, can be significantly slower than L1 or L2 cache, usually double speed of RAM

Answer 603

The performance increases CPUs with multiple cores have more power, allowing for more processes to be ran at the same time with greater ease

Answer 604

Primary: Volatile Short-term Directly accessed by CPU Limited storage capacity Secondary: Non-volatile Long-term Programs/data must be transferred to memory in order for them to be accessed by CPU Large storage capacity

Answer 605

Primary storage is needed to provide the CPU with fast, direct access to the program instructions and data that it is currently using - it only retains its contents temporarily Secondary storage is non-volatile and is needed to keep programs and data for the long term when not in use

Answer 606

Magnetic Optical Solid-state

Answer 607

Use of read-write heads that contain electromagnets Parts of surface is either magnetised (1) or demagnetised (0), read-write heads control this when writing and can tell what state surface of disk is in when reading

Answer 608

Write data: Laser used to burn pits and lands into surface of disk More reflective areas ‘lands’ represent 1s and less reflective areas ‘pits’ are 0s Read data: Laser beam shone onto surface of disk - light that hits a land reflects differently to where it hits a pit Amount of light reflected translates to 1s & 0s by a sensor

Answer 609

Write data: Electrical current applied to transistor, forcing electrons through a barrier and trapping them in pools Full pool represents 0 and an empty pool 1 Read data: Small voltage is applied If electron pool is empty, transistor turns on and 1 is read - if full, transistor does not turn on and 0 is read

Answer 610

Used in: HDDs Internal/external hard drives Tape drives Advantages: High capacity Fast data access Disadvantages: Has moving parts that will eventually fail Noisy

Answer 611

Used in: CD, DVD and Blu-ray drives Advantages: Portable Disks are cheap Disadvantages: Slow to access Prone to scratches

Answer 612

Used in: Solid-state drives USB sticks SSD cards Mobile devices and wearables Advantages: Very fast data access No moving parts Low power Quiet Disadvantages: Relatively expensive Has a limited number of read-write cycles

Answer 613

Data is stored and is accessible from multiple connected resources that comprise a cloud via the internet

Answer 614

Unlimited storage capacity - cloud computing offers limitless storage Automatic backup - hard disk crash could destroy valuable data that is stored on a device, but if the data is stored in the cloud, computer crash should not affect it Universal access - all documents and files stay in the cloud, can be accessed whenever you have a computer or phone with internet connection; all documents instantly available wherever you are Device independence - user not limited to having documents stored on a single computer or network, can change device and documents follow you through cloud

Answer 615

Requires a reliable internet connection, impossible without a connection Will not work as well with low-speed connections Large documents and images require a lot of bandwidth User loses control over what happens to data as this is managed by cloud service provider

Answer 616

A specific-purpose computer within a larger system

Answer 617

Specific-purpose No or minimal user interface Low power consumption Its functionality cannot be changed/upgraded by users Functions in real time Uses sensors to interact with external environment Has customised software and hardware Has limited, integrated memory Small physical size

Answer 618

A number assigned to the storage location so that it can be accessed.

Answer 619

Data is permanently lost when the power is switched off.

Answer 620

Basic Input/Output System

Answer 621

The BIOS system controls the computer when it is first switched on. It tests the system hardware and loads the operating system. It is specially written for each motherboard and performs any other operations that are needed by that particular motherboard.

Answer 622

Read-Only Memory

Answer 623

ROM is an integrated circuit on a chip. It is programmed with specific data to perform a particular function then it is manufactured.

Answer 624

the BIOS controls what happens when the computer is first switched on the BIOS checks the hardware devices to ensure there are no errors the BIOS loads basic software so that it can communicate with these hardware devices. It then locates and passes control to the operating system.

Answer 625

The data can be read but it cannot be changed; the computer cannot write to the chip, unlike RAM.

Answer 626

ROM is non-volatile as the data is not lost when the power is turned off.

Answer 627

A temporary store of program instructions and data.

Answer 628

RAM consists of billions of memory locations with unique addresses which can be accessed in any order.

Answer 629

Basic information and instructions that a computer needs when it is starting up (booting).

Answer 630

Programs that are called up by the systems software and which perform specific tasks.

Answer 631

When the computer is running the operating system and several applications.

Answer 632

a process running on the computer may need to store data in the physical memory. if there is no free memory, the memory manager will ‘swap out’ some of the data stored in RAM to the swap area on the hard disk drive and ‘swap in’ the requested data into the now free area. usually the least recently used stored data is swapped out. if data is swapped out and then is needed again, it is swapped back in, from the swap area, at the expense of the data.

Answer 633

the read/write speed of a hard drive is much slower than RAM, as the technology of a hard drive is not geared towards accessing multiple small pieces of data at a time. if the system has to rely too heavily on virtual memory, there will be a significant performance drop. often the operating system has to constantly swap information back and forth between RAM and the hard disk drive, which operates all of the time. You can hear the disk drive operating continuously. This is called ‘disk thrashing’ and significantly slows down the execution of programs.

Answer 634

Virtual memory is the use of secondary storage as additional primary memory.

Answer 635

Often the operating system has to constantly swap information back and forth between RAM and the hard disk drive, which operates all of the time. You can hear the hard disk drive operating continuously. This is called ‘disk thrashing’ and significantly slows down the execution of the programs.

Answer 636

The more RAM a computer has then the less virtual memory will be needed. Virtual memory has a much slower read/write speed as the technology of a hard drive is not geared towards accessing multiple small pieces of data at a time.

Answer 637

When a program or part of a program is run by the computer.

Answer 638

Devices that store information but which do not lose the data when they are switched off; usually not on the main circuit (motherboard).

Answer 639

Storing data using optical devices such as CDs and DVDs.

Answer 640

Storing data using devices such as flash memory. This is sometimes called ‘electrical’ storage.

Answer 641

magnetic storage optical storage solid state storage

Answer 642

magnetic storage optical storage solid state storage

Answer 643

Because RAM is volatile, data must be stored on devices called secondary storage devices so that the data is not lost when the power is turned off.

Answer 644

Optical storage uses light from lasers to read and write data on discs. To write data to a disk, a laser beam encodes data onto a disk via burning pits onto the disk’s surface in a spiral track.

Answer 645

CDs typically store 700MB.

Answer 646

DVDs typically store 4.7 GB.

Answer 647

Compact Disk

Answer 648

Digital Versatile Disk

Answer 649

cheap easy to transport from one site to another

Answer 650

less storage space than hard disk drives slow access speeds stored data degrades over time risk of disk scratching data cannot be written over unlike with hard disk drives

Answer 651

hard disk drives magnetic tape floppy disk drives

Answer 652

Hard disk drives consist of stacks of non-removable disks coated with magnetic materials. The disks spin and read-write heads move across them. Electro-magnets in the read-write heads read and write the data.

Answer 653

Storing data using magnetic media such as a hard disk drive.

Answer 654

Hard disk drives are suitable for the storage and backup of large amounts of data that do not need to be transported.

Answer 655

Optical disks are most suitable for distributing program files and images, and backing up data which can then be stored at another site.

Answer 656

not very portable susceptible to physical knocks that may cause the read-write heads to hit the disks and corrupt data

Answer 657

very fast access speeds random access: data can be read instantly from any part of the disc low cost can store large amounts of data; hard disk drives that store terabytes of data are common in most home computers

Answer 658

Solid State Drive

Answer 659

Secure Digital card

Answer 660

SSDs SD cards Micro SD cards SDXC (extended capacity) cards USB drives

Answer 661

256 GB - 1 TB

Answer 662

Data storage in cameras, mobile phones and embedded devices. It is also increasingly used as the main secondary storage device in computers, especially in laptops as SSDs.

Answer 663

Solid state memory devices are ideal for transporting data as they are light and have no moving parts which could be damaged.

Answer 664

very fast access speed; much faster than optical discs portable - small and light quiet has no moving parts that could be damaged if the device was knocked or dropped and therefore there is less chance of losing data

Answer 665

more expensive than a HDD or optical disc less storage capacity than a HDD limited number of erase/write cycles, up to 100000 for high quality SSDs and so it cannot be used indefinitely

Answer 666

capacity - very large speed - fast portability - not very portable as physical knocks may cause the read-write heads to hit the discs and corrupt the data durability - very durable reliability - very reliable cost - very low

Answer 667

capacity - low speed - slow portability - more portable than HDD but discs are still relatively slow durability - easily scratched and data can be damaged. Data cannot be overwritten reliability - very reliable if not scratched cost - very low

Answer 668

Off-site storage accessed over the internet.

Answer 669

The CPU carries out all of the program instructions by carrying out millions of calculations each second. These calculations are performed by billions of transistors acting as switches. The transistors are either on or off - they have two states, they either transmit an electric current or they do not.

Answer 670

The address in the PC is copied to the MAR PC increments Instruction stored at the location held by the MAR is copied to the MDR

Answer 671

Control Unit will decode the instruction and send control signals to the component that needs to act

Answer 672

The component that is needed performs the operation This may be the: ALU

Answer 673

It uses tiny resistors to create a heat bubble, which then forces ink out of a tiny nozzle as it expands. When the bubble collapses, it creates a vacuum sucking more ink into the cartridge.

Answer 674

It applies an electrical charge to piezoelectric crystals which vibrate inwards causing it to push ink out of a nozzle. When the crystals vibrate, it causes a vacuum which further causes more ink to draw into the cartridge.

Answer 675

PROS: - Cheaper to run - Better print quality CONS: - Print quality inferior to inkjet on photographic paper - Expensive to buy

Answer 676

PROS: - Cheap to buy - Good image quality if used with photographic paper CONS: - Higher running costs as it uses a lot of ink - Printing bleeds through paper

Answer 677

It uses a laser beam to give a photoreceptor drum a static charge. The static electricity causes toner to be attracted to the positively-charged areas of the drum. As the paper approaches the drum, it is given a strong positive electrical charged, which causes the toner to transfer onto the paper. The paper goes through a pair of rollers where the toner fuses into the paper.

Answer 678

A unique identifier hat is used to identify a device on the internet. It is a 12 character hexadecimal string that is broken down into 2 parts, first part is the manufacturer ID and second part is Unique serial number of that device.

Answer 679

Memory Dumps HTML colours

Answer 680

Unique address Public or Private Static or Dynamic

Answer 681

By pushing and pulling the surrounding air molecules in waves. The waves are created by moving a speaker cone with electromagnets.

Answer 682

It uses the light modulating properties of liquid crystals which can be changed into a solid or a liquid using an electrical field. The change of state allow light to shine through or to block it off for individual pixels. To get a colored display, we would need to add a layer of colored sub-pixels.

Answer 683

It works the same way as LCD but the light source is an array of LED bulbs.

Answer 684

They use an array of LEDs as pixels to produce the image.

Answer 685

Mechanical output device that is responsible for moving or controlling a mechanism.

Answer 686

It uses a large number of tiny mirrors which are arranged in a grid and can be tilted away or towards from the light source, reflecting light towards a projection lens. Each mirror creates one pixel in the projected image. To add color, the light passes through a color wheel.

Answer 687

Transfer of data from inside a computer to an external media.

Answer 688

Shines a laser onto the barcode and the barcode reflects the white spaces back. Photoelectric cells detect the reflected light and convert it to digital data which can be read by a computer.

Answer 689

A red LED light is reflected off a surface and any movements are detected be a sensor made up of an array of photo-sensitive diodes

Answer 690

Transfer of data from outside a computer to its main memory.

Answer 691

The computer retrieves a program instruction from its memory. Then it establishes and carries out the actions that are required for that instruction.

Answer 692

An extremely fast memory type that acts as a buffer between RAM and the CPU. It holds frequently requested data and instructions and can provide this immediately to the CPU when needed

Answer 693

Central Processing Unit The primary component of a computer that processes instructions. It runs the OS and applications. Constantly receiving inputs from the user. (+ CONTROLS FETCH-DECODE-EXECTURE cycle)

Answer 694

A type of storage medium that permanently stores data on personal computers (PC’s) and other electronic devices

Answer 695

A computer bus architecture. Used tp transfer data between devices. The devices are identified by

Answer 696

Instruction data and program data are stored in the same memory still used in most computers today

Answer 697

Data and Instructions

Answer 698

uses hardware and software to allow a computer to compensate for physical memory shortages (by temporarily transferring data from the RAM to HDD/SSD

Answer 699

using active memory in RAM and inactive memory in HDD’s to form connecting addresses that hold both the application and data

Answer 700

physical memory (RAM)

Answer 701

the hard drive

Answer 702

pagefiles (or swapfiles)

Answer 703

The OS copies it from the disk to the main memory and translates the virtual addresses into real addresses.

Answer 704

Primary Storage device (eg. RAM) - Secondary Storage device (eg. HDD)

Answer 705

Magnetic - Optical

Answer 706

HDD Floppy disk Tape cassette

Answer 707

Blu-ray disk CD-ROM CD-R and CD-RW

Answer 708

The surfaces of the disks and magnetic tapes are coated with million of tiny iron particles so that data can be stored on them. The write/ read heads contain electromagnets that generate magnetic field in the iron as the head passes over the disk or tape.

Answer 709

The data is recorded by making marks in a pattern that can be read back with the aid of light (usually a laser) which is precisely focused on the spinning optical disc

Answer 710

2D Scanners 3D scanners Barcode Scanners/readers

Answer 711

Most common form of scanners generally used to input hard-copy paper documents image is converted into electric form which can be stored in computer

Answer 712

1) cover raised, document placed on glass panel, cover closed 2) bright white light illuminates document, modern scanners usually use type of xenon lamp 3) scan head moves across document until whole page scanned 4) image of document produced and sent to a lens using series of mirrors, lens focuses image 5) focused image falls onto charge couple device (CCD) integrated circuits etched into silicon 6) CCD made of 1000s of light sensitive elements or pixels, each element creates electric charge when light falls on it 7) scanned image now turned into electric form, software produces digital image from electric form

Answer 713

OCR optical character recognition software, scanned image can now be edited and manipulated by importing into word processor

Answer 714

JPEG or another image file format

Answer 715

scan solid objects and produce 3D image solid objects have x,y,z coordinates scanner takes several points along these coordinates digital image which represents object is formed scanned image can be used in computer aided design, CAD, printed through 3D printer producing working model of scanned image

Answer 716

lasers magnetic resonance white light

Answer 717

used to read passports use OCR technology to produce image of passport page due to OCR tech digital images can be manipulated OCR can review image, select text part and automatically put it into existing database image of passport stored as jpeg passenger face photographed and compared to digital image of passport photo face recognition/detection software compares these two images

Answer 718

distance between eyes width of nose shape of cheek bones length of jaw line shape of eyebrows these key position are compared to see whether images belong to same face

Answer 719

used to create image of 3D object based on tomography technology builds up an image of object through series of very thin slices each slice built by use of X ray, radio frequencies, or gamma imaging each slice stored as digital image in computer memory whole of solid object represented digitally in computer memory

Answer 720

X ray - CT scanners - computerised tomography gamma ray - SPECT - single photon emission computed tomography radio frequency - MRI - magnetic resonance imaging

Answer 721

Universal Product Code

Answer 722

series of dark and light parallel lines of varying thickness The numbers 0 to 9 are each represented by a unique series of lines

Answer 723

adopts different codes for digits appearing on the left and for digits appearing on the right

Answer 724

guard bars (two thin lines)

Answer 725

7 thin bars coloured black and white

Answer 726

they are the inverses of each other, anything coloured black on left side for same number will be white on right side

Answer 727

can be scanned in any direction

Answer 728

barcode read by red laser or red LED (light emitting diode) light reflected off barcode dark areas reflect little light or no light, white areas reflect more light which allows bars to be read reflected light read by sensors photoelectric cells as LED light scanned across barcode, pattern generated and converted to digital data this allows computer to understand barcode

Answer 729

at the checkout at supermarket

Answer 730

barcode number looked up in database, barcode is known as the key field in stock item record key field uniquely identifies each stock item when barcode number found stock item record looked up price and other stock item details sent to checkout or point of sale terminal POS number of stock items in record reduced by one each time barcode is read new value for number of stock items is written back to the stock item record number of stock items is compared to the re-order level; if less than or equal to value, more stock items are automatically ordered. Once an order for more stock items is generated, a flag is added to the record to stop re-ordering every time the stock item barcode is read. When new stock items arrive, the stock levels are updated in the database.

Answer 731

* much easier and faster to change prices on stock items * much better, more up-to-date sales information/sales trends * no need to price every stock item on the shelves (this reduces time and cost to the management) * allows for automatic stock control * possible to check customer buying habits more easily by linking barcodes to, for example, customer loyalty cards.

Answer 732

faster checkout queues (staff don’t need to remember/look up prices of items) errors in charging customers are reduced the customer is given an itemised bill cost savings can be passed on to the customer better track of ‘sell by dates’ so food should be fresher.

Answer 733

library: borrowing books, borrower’s library card Every time a book is taken out, the borrower is linked to the book automatically. This allows automatic checking of when the book is due to be returned, for example.

Answer 734

Quick Response codes, another type of barcode

Answer 735

made up of a matrix of filled-in dark squares on a light background

Answer 736

CPU is a central processing unit A CPU is the portion of a computer that retrieves and executes instructions

Answer 737

A device that receives or displays output from a computer system

Answer 738

monitors Printers speakers projectors

Answer 739

microphone Keyboard Mouse

Answer 740

larger or multiple programs

Answer 741

A device that reads and writes data from secondary storage

Answer 742

CD DVD Blu-ray

Answer 743

Secondary storage is non-volatile whilst Primary is volatile Secondary storage is not directly accessed by the CPU whilst Primary storage is directly accessed by the CPU. Secondary storage typically have have more memory capacity than Primary storage.

Answer 744

Data is written with a laser burning “pits” and “lands” into the disk. These reflect light differently which is how it is interpreted as binary when reading data. When reading the disk, it spins and a light is reflected off of the surface and the reflections are then interpreted as data.

Answer 745

Good portability Cheap

Answer 746

Magnetic storage has read and write heads which contain electromagnets. These electromagnets magnetize or demagnetize parts of the surface to represent binary. The data is read with the read head.

Answer 747

Doesn’t have a large memory capacity Can be scratched easily which makes data inaccurate

Answer 748

Large memory capacity Cheap per unit of storage

Answer 749

Can create noise Data can be erased by nearby magnets High power consumption

Answer 750

Solid state storage works by controlling the movement of electrons within NAND or NOR chips. The data is stored as 1s and 0s in millions of transistors within the chip.

Answer 751

Does not make any noise because no moving parts Durable and not affected by physical shock Fast access times

Answer 752

Expensive Limited read/write cycles

Answer 753

This is when data is stored remotely in server farms or data warehouses

Answer 754

Can access data anywhere on any device

Answer 755

Cannot access without internet Susceptible to cybercrime Can be expensive

Answer 756

When RAM is too full there need to be some way for the CPU to execute instructions that are not currently available in RAM

Answer 757

An area of memory in secondary storage is found Unused and inactive instructions in RAM are moved to that area in secondary storage Pages of required instructions are moved from secondary storage into the RAM The CPU can now access the instructions it needs Once complete, the instructions can be moved back into the RAM from secondary storage

Answer 758

Underneath each key on the keyboard there is a small peg, which sits inside a hole in the keyboard’s base. As you push down on the key, the peg pushes through the hole to touch the contact layers below. The contact layers consist of 2 conducting layers separated by an insulation layer which keeps them apart. A electrical signal is created when the peg pushes the layer together which tells us that a particular key has been pressed

Answer 759

A red LED light is reflected off a surface and any movement is picked up by sensors made up of an array of photo-sensitive diodes.

Answer 760

Pushing on the screen makes 2 conductive layers make that are separated by an insulating layer make contact which creates an electrical signal and we can figure out the position of the contact by a microprocessor.

Answer 761

Human bodies can act as an electrical conductor So when we touch the screen we distort its electrostatic field The position of the distortion can be interpreted by a microprocessor

Answer 762

They utilize an array of LED beams which have corresponding detectors So it can detect touch events

Answer 763

Diaphragm vibrates when hit by sound waves Vibrations are detected and converted into an electrical signal using an ADC

Answer 764

When the shutter opens, light falls onto the charge-coupled device array which breaks it up into millions of pixels The sensor measures color and brightness of each pixel and stores it as a number Digital photographs are simply a file consisting of information about each pixel and meta-data about the file itself

Answer 765

It uses an array of light-sensitive diodes on a charge-coupled device sensor This converts light into an electrical charge Bright light illuminates the documents and a scan head goes across Mirrors and lenses reflect the documents onto the diodes and the varying electrical charges are converted into digital values

Answer 766

MIDI for short the storage of music files - consists of lists of commands which instruct a device on how to produce a musical note/sound

Answer 767

uses audio compression to store music in MP3 file format

Answer 768

can store multimedia rather than just music

Answer 769

JPEG uses a lossy format file compression method to store photographs at a reduced file size

Answer 770

all the data from the original files are reconstructed when the file is uncompressed

Answer 771

unnecessary data is removed forming a file that cannot be reconstructed to its original file

Answer 772

RAM, SRAM, DRAM, ROM

Answer 773

hard disk drives solid-state drives offline storage (CDs, DVDs, DVD-RAM, DVD-ROM and blu-ray disks)

Answer 774

don’t contain actual audio tracks suitable for storing sounds/music on devices with limited memory

Answer 775

removing sounds that the human ear can not clearly distinguish

Answer 776

ASCII file format lossless: accuracy of data is important

Answer 777

does not need to be constantly refreshed to retain its data uses flip-flops

Answer 778

needs to be constantly refreshed to retain the data uses millions of transistors and capacitators

Answer 779

used to store start-up procedures or BIOS

Answer 780

circular platters coated in magnetic material

Answer 781

read-write heads

Answer 782

sectors and tracks in block

Answer 783

the time taken for a specific block of data on a track to rotate around to the read-write head

Answer 784

they have no moving parts all data retrieved at the same rate therefore no latency

Answer 785

NAND chips

Answer 786

more reliable and robust (no moving parts) much lighter and thinner consumer less power and run cooler does not need to get up to speed faster data access rate

Answer 787

red laser light

Answer 788

write once and then only be read

Answer 789

can be written to and read from several times

Answer 790

dual layering technology (they have two individual recording layers)

Answer 791

uses a number of concentric tracks enabling simultaneous read-write operations to take place

Answer 792

they have great longevity

Answer 793

blue laser light

Answer 794

wavelength of blue light is 405nm wavelength of red light is 650nm can store more data

Answer 795

they use single polycarbonate disks rather than DVDs which use a sandwich of two polycarbonate disks

Answer 796

solid-state technology

Answer 797

small and lightweight

Answer 798

read every now and again

Answer 799

Monitoring a process: Sensors send data Data converted to digital data (using ADC) Computer analyses/compares data If outside the range (when compared to stored values) . . . . . . it sends a signal to sound alarm or produce warning message on a screen. Controlling a process: (First four lines are the same as above) . . . it sends signals to actuators Signals converted to analogue using DAC Pumps/va lves (etc.) are opened/closed (etc.) to alter the process conditions The output affects the next input.

Answer 800

Data gathered from temperature and pH sensors Signals sent to ADC where they are converted to digital Information is sent to the computer where it is compared to pre-set/stored values If the temperature 30°C, a signal is sent by the computer to the motors to open the windows (again DAC and actuators used) and to switch off the heaters If the temperature is between 25°C and 30°C, no action is taken If the pH 5, a signal is sent by the computer to open valves to add acidic water (again use of DAC and actuators) If the pH is between 4 and 5, no action is taken In all cases, the output from the system will affect the next input to the system Alarm is sounded if there is an error in the system Monitoring and control continues until system turned off.

Answer 801

Light sensor - automatic doors in a hotel Acoustic sensor - picks up sounds, for example,a burglar alarm Infra red sensor - counting items every time the beam is broken.

Answer 802

Many monitoring and control applications do not use a computer system; a microprocessor is used instead but the methodology and the outcome are the same.

Answer 803

Actuators are used in many control applications involving sensors and computers or m icroprocessors. They are usually electromechanical devices such as a motor, relay or solenoid. Actuators can be digital (solenoid) but others require a digital to analogue converter (DAC) since the actuator needs an electric current/voltage to operate a motor or a valve, for example.

Answer 804

(i) Two problems - out of paint - component is m issing - something is obstructing the paint spray gun. (ii) Use of sensors to detect out of paint, item is in the correct position, something is obstructing the spray gun, etc Use of CCTV/cameras to show the status of the process (e.g. these can check paint surface of a car for imperfections).

Answer 805

Advantages: Can work in conditions hazardous/unpleasant to humans; They can work non-stop (no breaks); Less expensive in the long run (no wages required); More productive (takes less time to do a task than a human); More consistent (everything is always made to the same standard); Removes the need for humans to do boring/ repetitive tasks; Less factory costs (can reduce heating, lig hting levels, etc.). Disadvantages: Difficulty dealing with non-standard situations; Can lead to unemployment; Possible risk of deskilling; Production process can be more easily moved to ‘less expensive’ countries.

Answer 806

Pointing devices such as mouse - Touch screens

Answer 807

Com mand line interface: Direct communication with computer; Increases flexibility (G UI is very restricted); Graphical user interface: No need to understand how computers work; Much quicker/easier to find and open applications rather than have to type in a series of instructions.

Answer 808

(a) - Sensors pick up proxim ity of objects Sensors pick up information from surroundings to make sure trave l ling Straight or can turn when path bends - Data is sent to the computer - This data is analysed by the computer - Signals sent to wheels/motors to turn vehicle as needed (also use of DAC and actuators).

Answer 809

Capacitive Benefits - this is a medium cost tech nology - screen visibi l ity is good even in strong sunl ight - it permits multi-touch capability - the screen is very durable; it takes a major impact to break the g lass Drawbacks - allows only the use of bare fingers as the form of input; although the latest screens permit the use of a special stylus to be used Infra red Benefits - both systems al low mu lti-touch capabilities - the optical system allows the use of bare fingers, gloved fingers or stylus for input - both systems have good screen durability; it takes a major impact to break the glass Drawbacks it is a relatively expensive technology heat sensitive system only a llows bare fingers to be used for input (gloved fingers or stylus don’t work) both systems (optical and heat sensitive) have fairly good screen visibility in strong sunlight. Resistive - this makes use of an upper layer of polyester (a form of plastic) and a bottom layer of g lass - when the top polyester layer is touched, the top layer and bottom layer complete a circuit - signals are then sent out which are interpreted by a microprocessor; the calculations determine the coordi nates of where the screen was touched. Benefits - it is relatively inexpensive technology - it is possible to use bare fingers, gloved fingers or stylus to carry out an input operation. Drawbacks - screen visi bility is poor in strong sunl ight - it doesn’t permit mu lti-touch capability - the screen durability is only fair; it is vul nerable to scratches and the screen wears out through time

Answer 810

sensors continuously send data to the microprocessor if the output from the sensors is analogue, then the data is converted to digital, using an ADC, before it is sent to the microprocessor the microprocessor contains optimum temperature and acid/pH val ues (or they are stored on a storage device connected to the microprocessor) if the temperature reading is = 50°( then no action is taken if the pH reading is > 5, then a signal is sent to a valve to open and allow acid to enter chemical process if the pH

Answer 811

A structure in which the hardware is connected and organised. It consists of Main Memory and a Central Processing Unit interconnected by buses. __________Main Memory ________ (Read)!_____¡(Write) Input –> Central Processing Unit –> Output The CPU reads and writes data & program instructions to and from main memory.

Answer 812

Known as Random Access Memory(RAM) It stores the data & programs the CPU can access. Volatile - Loses content when power is lost. Faster and more expensive than secondary storage

Answer 813

A computer that is multi-purpose, can be programmed to carry out different tasks. They are able to store program instructions and data in main memory.

Answer 814

Consists of: - Control Unit (CU) - Arithmetic Logic Unit (ALU) - Registers

Answer 815

Decodes instructions received from main memory Coordinates the actions of other components

Answer 816

Performs arithmetic and logic operations on data.

Answer 817

Provides fast, temporary storage for instructions.

Answer 818

Buses connect the components inside a computer. Types: - Address bus - Data bus - Control bus