3. hardware

Question 1

what is the cpu

Answer 1

An integrated circuit which accepts data input into the computer and processes it into information ready for output.

Question 2

what is a microprocessor

Answer 2

An integrated circuit which accepts data input into the computer and processes it into information ready for output. Sometimes used interchangably with Central Processing Unit (CPU), but not all microprocessors are CPUs.

Question 3

what are the components of a cpu

Answer 3

control unit
arithematic logic unit
registers:
-pc
-mar
-mdr
-cir
-acc
buses:
-control bus
-address bus
-data bus

Question 4

control unit

Answer 4

manages the other components of the CPU and the overall operation of the CPU. This includes initiating each step of the fetch-decode-execute cycle and managing the Arithmetic Logic Unit

Question 5

arithmetic logic unit

Answer 5

responsible for carrying out mathematical calculations or logical operations, uses the Accumulator (ACC) register to temporarily store data while performing these calculations.

Question 6

what are registers

Answer 6

small areas of storage found within the CPU. The register size depends on the CPU model, Registers are extremely fast to access because they are located directly within the CPU.

Question 7

PC register

Answer 7

holds the address (memory location) of the next instruction to be fetched.

Question 8

MAR register

Answer 8

used when reading data from RAM or writing data to RAM. The MAR will contain the address of the RAM location to be written to or read from.

Question 9

MDR register

Answer 9

used when reading and writing data to and from RAM. The MDR will contain the data to be written to RAM, or the data that has just been read from RAM

Question 10

CIR register

Answer 10

holds the instruction which is currently being decoded or executed.

Question 11

ACC register

Answer 11

used to hold the data being worked on by the ALU

Question 12

what are buses

Answer 12

A bus is a way of communicating between two components, there are three which carry different type of data

Question 13

address bus

Answer 13

carries addresses from the Memory Address Register to RAM, to indicate which address will be selected. The address bus is a unidirectional bus – it only carries addresses in one direction (to RAM).

Question 13

control bus

Answer 13

A communication channel that carries control signals within the CPU and between the Control Unit of the CPU and RAM.

Question 14

data bus

Answer 14

During a write operation, the data bus carries the data to be written from the Memory Data Register to RAM. During a read operation, the data bus carries data from RAM to the Memory Data Register. The data bus is bidirectional – it carries data to and from RAM.

Question 15

what is the fetch decode execute cycle

Answer 15

a simple cycle to run programs

Question 16

basic steps in the fetch decode execute cycle

Answer 16

Fetch: An instruction is fetched from RAM to the CPU.
Decode: The instruction is ‘decoded’ by the Control Unit (CU) to determine what type of instruction it is.
Execute: The instruction is executed. This is usually performed by the Arithmetic Logic Unit (ALU). Some instructions may involve reading additional data from RAM (for example, reading a number which is to be added to a value in a register). Executing an instruction will also often include storing the result.

Question 17

describe the fetch procedure

Answer 17

The Program Counter (PC) contains the address of the next instruction.
The contents of the PC are copied to the Memory Address Register (MAR).
The PC is incremented by 1, so that it still points to the next instruction.
The address bus carries the value in the MAR to RAM.
The control bus sends a ‘read’ signal to RAM.
The data bus carries the contents of the desired RAM address from RAM to the Memory Data Register (MDR).
The contents of the MDR is copied to the Current Instruction Register (CIR).

Question 18

describe the decode procedure

Answer 18

The Control Unit (CU) decodes the instruction in the CIR.

Question 19

describe the execute procedure

Answer 19

The instruction is sent to the Arithmetic Logic Unit (ALU) to be executed.
The ALU may use the Accumulator (ACC) to temporarily store its results.

Question 20

what affects cpu speed

Answer 20

clock speed number of cores and size of cache

Question 21

clock speed

Answer 21

speaking, the clock speed determines the number of cycles a CPU can perform each second,Higher clock speeds generate more heat and use more energy slowing down cpu performance

Question 22

cores

Answer 22

A core is a processor within a CPU.a single core can only work on one instruction at a time. This limited the performance of earlier CPU designs

Question 23

cache

Answer 23

extremely fast memory that is located within the CPU. It is used to store temporary copies of the data in the most commonly accessed RAM locations

Question 24

what are instruction sets

Answer 24

An instruction set is a list of all the commands that can be processed by a CPU and the commands are machine code

Question 25

what is an embedded system

Answer 25

An embedded system is used to perform a
dedicated function, e.g. domestic appliances, cars, security systems, lighting systems or vending machines. This is different to a general purpose computer that is used to perform many different functions, e.g. a personal computer (PC)
or a laptop

Question 26

what is an input device

Answer 26

A hardware device used to enter data into a computer system

Question 27

barcode scanner

Answer 27

input device:
Barcode scanners shine a light at a barcode and measure the reflected light to read the data. This is quicker than typing in the barcode number manually.

Question 28

digital camera

Answer 28

input device:
A digital camera uses an image sensor to measure light and take a photograph, which is stored digitally on a device such as an SD card. Many digital cameras can record both still images and video.

Question 29

keyboard

Answer 29

input device:
Keyboards are one of the most common input devices, allowing users to type text and numeric data quickly. Keyboards may have a standard layout
may be concept keyboards with custom layouts. For example, on a keyboard used in a restaurant one particular key may order a drink and another may order a burger

Question 30

microphone

Answer 30

input device:
A microphone allows sound to be input. The sound could be recorded for playback, or used together with voice recognition software to turn it into text or commands.

Question 31

optical mouse

Answer 31

input device:
A mouse is commonly used to control a cursor or pointer on screen. Most mice have at least two buttons, but some have more.

Question 32

QR code scanner

Answer 32

input device:
A QR (quick response) code is similar to a barcode. It consists of a square black and white pattern which represents a small number of text characters (usually fewer than 100). QR codes are often used to store URLs to connect users directly to websites. A QR code is read using a digital camera.

Question 33

touch screen (resistive, capacitive and
infra-red)

Answer 33

input device:
Touch screens allow users to input data by pointing and touching options with their fingers

resistive:
use two very thin metal sheets over the screen. When the user applies pressure to the screen these two metal sheets make contact, completing an electrical circuit. This can be used to detect exactly where the user pressed.

capacitive:
use a transparent layer over the screen. This layer is sensitive to the static electrical charge in the human body. When the user touches the screen, this charge is detected and the touch location can be determined.

infrared:
create a grid of infra-red (IR) light over the screen. This grid is invisible to users. When the user touches the screen, the light beams are broken. This information can be used to detect the location of the touch.

Question 34

2d scanner

Answer 34

input device:
documents are laid flat on the device and light is used to scan the document into a digital image.

OCR (optical character recognition) software can scan text documents and turn them into editable text in a word processor.

Question 35

3d scanner

Answer 35

input device:
can take measurements of objects in order to create a 3D computer model of them. It does this by scanning an object using lasers to measure the dimensions (height, width, depth) of an object. The laser detects details about the shape of the object and converts this into digital data

Question 36

output device

Answer 36

A device used to present information from a computer in a human-friendly format. Examples include printers, screens and speakers.
1. light shined into code using camera
2. light hits image and bounces back
3. electrical signals converted to digital using adc
4. scanner combines digital data into an image
5. image processed by scanner (rotates qr code)
6. data read from qr code
7. data used by device

Question 37

actuator

Answer 37

output device:
An actuator takes a digital signal and outputs it as a physical movement. For example, in an automatic door system the computer might send a signal to open the door and an actuator would convert this into a motor movement that causes the door to open.

Question 38

digital light processing (DLP) projector

Answer 38

output device:
use thousands of tiny mirrors to reflect a digital image from a computer onto a screen.

DLP projectors are usually smaller and more portable than LCD projectors, but LCD projectors produce higher quality images than DLP projectors.

Question 39

inkjet printer

Answer 39

output device:
use ink cartridges to spray tiny droplets of ink at a piece of paper to form an image. Inkjet printers are comparatively cheap and, although they can be slow, they can produce high-quality images with excellent colour blending.

Question 40

laser printer

Answer 40

output device:
use a laser to apply a static charge to areas on the paper. Toner (a powdered ink) is then attracted to the static charge and sticks to the paper in these areas, forming an image.

Laser printers produce higher quality text documents than inkjet printers, but inkjet printers produce better quality colour gradations on images and photos. Laser printers can print faster than inkjets, but they are more expensive.

Question 41

light emitting diode (LED) screen

Answer 41

output:
function in a similar way to LCD displays. The main difference is the type of back light. Instead of using a fluorescent backlight, LED displays use light emitting diodes to generate the light. This often results in better contrast.

LED displays generally produce better image quality than LCD displays, with better contrast and colour reproduction. They use less electricity than LCD displays, making them more cost effective in the long run. However, their initial cost is higher.

Question 42

liquid crystal display (LCD) screen

Answer 42

output:
work by sandwiching crystals between two sheets of glass. A white back light illuminates the screen from behind. When the crystals are solid, light cannot pass through. When an electrical current is applied to the crystals in individual pixels, light is passed through and an image forms.

Question 43

liquid crystal display (LCD) projector

Answer 43

output:
create an image by projecting light in three colours: red, green and blue. These colours are combined to form a final image on the projector screen.

Question 44

speaker

Answer 44

output:
A speaker produces output in the form of sound, by converting electrical signals into vibrations.

Question 45

3-d printer

Answer 45

output:
3D printers are relatively modern output devices that can print physical objects. They do this by building up thin layers of material, layer by layer, until the object is complete. Objects are usually created from plastic filaments (such as ABS or PLA plastic) or from resin.

Question 46

sensors

Answer 46

are a specific type of input device, used to gather information about the physical environment for direct input into a computer

Question 47

sensors general answer:

Answer 47

-sensor send data readings to microprocessor at set intervals
-to be understood this data may have to be converted using an ADC (analogue to digital converter)
-microprocessor compares data against pre set values that it has stored
-microprocessor makes decision as to wheather any action is needed
-if needed the microprocessor send signal to instruct output device to do something, may involve actuator
-this process repeats in loop

Question 48

what is meant by primary storage + example and explanation

Answer 48

Primary storage is directly accessed by the CPU, there are RAM and ROM
RAM:
used for temporary storage of programs and data that are currently being used, extremelly fast to access, volatile
ROM:
contains data that can be read but cannot be altered or deleted. non volatile.ROM is essential because it contains the first instructions the computer needs when it is turned on

Question 49

what is secondary storage + examples and explanations

Answer 49

are not directly accessible by the CPU. non volatile, ideal fro storing users permamenent data, larger storage capacities.
examples:
hard disk drive, CD-ROM, DVD, blue ray, flash drive, sd card

Question 50

what are the 3 types of secondary storage devices

Answer 50

Magnetic storage
Optical storage
Solid-state storage

Question 51

explain magnetic storage + examples

Answer 51

devices store data by applying a magnetic charge to a magnetised material, cheap, fast, hold large amount of data
eg. hard disk drive

Question 52

explain optical storage + examples

Answer 52

measuring reflected light from tiny ‘pits’ and ‘lands’ on the disc surface. On the disc surface, there are microscopic ‘high’ and ‘low’ points, called ‘lands’ and ‘pits’. When a laser is pointed at the disc surface, the lands reflect light while the pits scatter light. This information is then interpreted as binary data by a light sensor
eg.compact Discs (CDs), Digital Versatile Discs (DVDs) and Blu-ray Discs
low storage capacities, slow, light, longer term storage

Question 53

solid state devices + examples

Answer 53

Solid-state devices storage data using electronic circuits which are created using transistors, used to represent binary data
eg.solid-state drives, memory cards and USB flash drives
more durable, produce less heat require less power, excellent portable

Question 54

what is virtual memory

Answer 54

A system that allows a computer’s operating system to use secondary storage as though it were RAM.hen more RAM is needed than is available, a chunk of data called a page is moved from RAM to virtual memory (secondary storage). This is called ‘paging out’ and frees up space in RAM. however slower to access than RAM

Question 55

what is cloud storage

Answer 55

Instead of using local storage on a user’s computer (such as a hard disk drive), cloud storage uses servers on the internet.Cloud storage can be accessed remotely in
comparison to storing data locally.user can access their files from anywhere with an internet connection, and reduces the need for local storage. However, because the data is not stored on the user’s computer, they must have a working internet connection to access their files.

Question 56

advantages and disadvantages of
storing data on the cloud in comparison to
storing it locally

Answer 56

local:
Data only be accessed on the local computer, take your computer or device with you.
Data is accessible even if there is no internet connection.
fast accessibility
risk of hardware failure, should have backups
initial cost may be higher but no monthly costs
data fully under users control

cloud:
data can be accessed from any device
internet connection is necessary
slower to access
at risk from unauthorised access. However, most cloud service providers have excellent security features.
also hardware failure in data centers, must have backups
initial cost may be lower but monthly fees

Question 57

what is a NIC

Answer 57

network interface card, a hardware device that is needed to connect a computer to a network

Question 58

what is a MAC address and what is its purpose + structure

Answer 58

All network interface cards have a unique address assigned to them when they are manufactured. This address is known as the media access control (MAC) address. MAC addresses are unique for every network card created and they cannot be altered.
48 bits long written in hexadecimals first 24 bits are manufacturer codes and last 24 automatically generated serial number

Question 59

what is an IP address

Answer 59

a unique address assigned to each computer on a network. IP addresses are essential for identifying and managing computers on the network

Question 60

what are the types of IP address + explanation for each

Answer 60

static IP address:
An IP address which is always the same for a particular device every time it connects to a network.
dynamic IP address:
An IP address which is assigned each time a device connects to a network.

Question 61

what are differences between IPV4 and IPv6

Answer 61

4-An older form of IP address, that uses 32 bits.
6-A more modern form of IP address, that uses 128 bits. written in hexadecimal

Question 62

what is a router in a network

Answer 62

are hardware devices used to connect devices together to form a local area network (LAN). They can also be used to connect multiple LANs to each other to form a wide area network (WAN).

Question 63

roles of router in a network

Answer 63

They allow devices to connect to a LAN
They can assign IP addresses to devices joining a LAN
They connect a LAN to the internet
They send (route) data to the correct destination on a network, and faster route