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CCEA AS Digital Technology > U2T3 (1) - Hardware + Software > Flashcards

U2T3 (1) - Hardware + Software Flashcards

1
Q

What is a computer system?

A

A system that is able to take a set of inputs, process them + create a set of outputs which is done by a combination of hardware + software.

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2
Q

What do you need for processing to take place? What is this system called?

A

A program which is a set of instructions. A stored-program computer.

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3
Q

What are the internal components of a computer system?

A

Motherboard, CPU, hard drive, RAM memory, graphics card, optical drive, power supply + heat sink/fan.

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4
Q

What is inside the CPU? Other names?

A

Control unit (CU), memory (cache) + arithmetic + logic unit (ALU) - Processor/central processing unit.

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5
Q

What does the CU do?

A

Control operation of CPU + hardware components by following program, organises storage + transfer of data using internal memory + special registers, performs fetch-decode-execute cycle by using register to step through instructions in sequence.

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6
Q

What do these mean?:

Fetch, decode, execute.

A

An instruction is copied from memory to CPU.
Meaning of instruction is determined.
Appropriate action is taken/calculation performed.

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7
Q

What does the ALU do?

A

Calculations (+/-/x/divide), comparisons (>/=), logical functions (and/or/not), bit-shift operations (shift bits in word right/left) Contains decoder + registers too.

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8
Q

What is the decoder?

A

Logic circuit to take binary rep of instruction + initiate execution of instruction. Part of ALU.

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9
Q

What are the registers?

A

Small pieces of memory inside CPU. Hardware version of variable in software.

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10
Q

What are the 3 steps that computers go through?

A

Input, process, output.

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11
Q

What are the 3 types of memory in the IAS? What is the IAS?

A

Immediate access store.

RAM, ROM + cache.

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12
Q

What is RAM? Typical size in computer?

A

Temporarily stores programs/data currently being executed. Content can be changed as it is temp. When programs are loaded from hard drive they are put into RAM. Allows programs to be quicker. 512 MB. Volatile. Read to/written from.

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13
Q

What is ROM?

A

Perm stores booting up part of operating system program. Non-volatile. Read from, not written to.

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14
Q

What is cache memory?

A

Fast access RAM close to CPU. Stores recent + frequent files. Volatile. Used by proxy server.

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15
Q

What are the registers in the CPU? (6)

A

IR, MDR, MAR, PC, ACC, general purpose.

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16
Q

What is the IR and what does it do?

A

Instruction register holds instruction currently being executed.

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17
Q

What is the MDR and what does it do?

A

Memory Data Register/memory buffer register/data buffer holds data that has been fetched from memory.

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18
Q

What is the MAR and what does it do?

A

Memory Address Register holds address of next piece of memory to be fetched.

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19
Q

What is the PC and what does it do?

A

Program Counter holds address of next instruction to be fetched from memory. Automatically incremented between supplying address of next instruction + instruction being executed.

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20
Q

What is the ACC and what does it do?

A

Accumulator is an internal CPU register used as default location to store calculations performed by ALU.

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21
Q

What are the general purpose registers used for?

A

Store transient data required by program. e.g. when a program is interrupted, its state may be saved here, ready for recall when it’s ready to start again.

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22
Q

What is the state of a program?

A

Value of registers e.g. PC/IR/MAR

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23
Q

If a CPU has ___ registers available, it will work faster.

A

More

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24
Q

What is the fetch-decode-execute cycle?

A

The sequence that is completed for each instruction in a program.

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25
Q

Describe each step of the fetch-decode-execute cycle?

A

Data + program that acts upon it are loaded into main memory (RAM) by operating system. PC copies address of next instruction into MAR, MAR places address onto Address bus, MAR triggers read signal causing RAM to place instruction onto data bus, this is loaded into MDR which copies it into IR. Decoded from instruction set in CPU and areas are prepared for execution. Instruction is now executed and CPU sets up for next cycle.

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26
Q

What are the 4 key factors of about CPU architecture that affect its performance?

A

Cores, clock speed, cache size + processor type.

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27
Q

What processing units does the CPU contain? What does eat unit contain? How many units might it have and why?

A

Cores. ALU, control unit & registers. 2 (dual), 4 (Quad) or even more. Runs multiple programs at the same time.

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28
Q

If I double the number of cores from 2 to 4, how much does my speed increase?

A

It won’t double as some is used up in communicating with each other through channels.

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29
Q

What is the clock speed?

A

Clock rate, indicates how fast the CPU can run. Measured in MHz or gHz and corresponds with how many instruction cycles the CPU can deal with in a second.

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30
Q

What happens in a faster CPU?

A

It uses more energy and creates more heat.

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31
Q

If my CPU works at 2 gHz, how many cycles can it complete in a second?

A

2 billion

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32
Q

Does the computer have a max clock speed? How can you increase it? What is this known as?

A

Yes. Changed in computer BIOS, overclocking.

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33
Q

Why is overclocking a bad idea?

A

There are limits to how fast a CPU can run and its circuitry may not keep up with speed. If clock tells CPU to execute instructions too fast, the processing won’t be completed before the next instruction is carried out, it this happens then the data is corrupted and the CPU can overheat.

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34
Q

What is cache?

A

A small amount of memory which is part of the CPU and faster as it is closer than RAM. It is used to temporarily hold instructions and data that the CPU may reuse.

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35
Q

How does cache work?

A

CPU control unit checks cache for instructions before requesting data from RAM so it is faster.

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36
Q

How is cache graded?

A

Level 1 (L1), Level 2 (L2) + Level 3 (L3)

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37
Q

How do the different cache grades work?

A

L1 Is part of CPU chip, smallest + fastest, 8KB to 64KB.
L2 + L3 are bigger extra caches between CPU + RAM. Slightly slower than L1. Each core has their own L1 but may share L2 + L3.

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38
Q

What are the 2 man types of CPU?

A

CISC (Complex Instruction Set Computing) + RISC (Reduced Instruction Set Computing)

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39
Q

What uses CISC?

A

Desktop/laptop computers use CISC architecture made by Intel/AMD

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40
Q

What uses RISC?

A

Smartphones + tablets use RISC ARM Architecture

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41
Q

What are the main differences between CISC + RISC?

A

Instructions, physical size, speed, energy consumption, design + cost.

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42
Q

In what way do instructions differ between CISC + RISC?

A

RISC has fewer instructions as CISC usually have hundreds. RISC must combine simple operations to do complex tasks so RISC is more efficient at performing simpler tasks.

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43
Q

In what way does physical size differ between CISC + RISC?

A

CISC are larger and require more silicon.

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44
Q

In what way does speed differ between CISC + RISC?

A

RISC run at a lower clock speed and perform simpler tasks faster but complex tasks slower but this works as smartphones/tablets are not used for such intensive tasks as playing hi-spec advanced games.

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45
Q

In what way does energy consumption differ between CISC + RISC?

A

CISC use more electricity and RISC can go into sleep mode when not actively accessing a program.

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46
Q

In what way does design differ between CISC + RISC?

A

Smartphones/tablets combine their processing architecture into an SOC and don’t have space for heat sinks or fans. As RISC are smaller, more functions (memory, hardware etc) can be combined with CPU in 1 chip. CISC are built into a system with a heat sink + fan for cooling.

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47
Q

What is an SOC?

A

System On a Chip

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48
Q

In what way does cost differ between CISC + RISC?

A

RISC uses less power and is cheaper to make.

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49
Q

What are backing storage devices also known as? What type of storage is it?

A

Secondary storage. Devices which hold programs + data when not in use. Non-volatile.

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50
Q

Give the 3 types of backing storage devices?

A

Magnetic, optical + flash.

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51
Q

Give 2 examples of magnetic storage devices?

A

Tape streamer + magnetic disks

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52
Q

Give 5 examples of optical storage devices?

A

CD-ROM, CD-R, CD-RW, DVD, Blu-Ray.

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53
Q

Give 4 examples of flash memory storage devices?

A

SD card, xD card, memory stick, CompactFlash.

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54
Q

Describe tape streamers.

A

AKA Magnetic Tape. Serial/sequential access. Not used to spree frequently used data, just backups and long term storage because it takes a long time to read the data. Main form in medium sized organisations, can be very large, hundreds of Gbs.

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55
Q

Describe the structure of a tape streamer?

What speed of access is it nowadays?

A

Data is stored on a strip of plastic covered in a magnetic coating. Tracks of data run along the tape with each track divided into frames of data.
Up to 80Mb/s.

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56
Q

What is a frame?

A

A set of bits that run across a magnetic tape which are read together by the read/write head.

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57
Q

What is serial/sequential access?

A

To get to any piece of data, all the stored data before that piece on the storage medium must be read through to find it. This makes it very slow.

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58
Q

What are the advantages of tape streamers?

A

Cheap per Mb storage, can store lots of data (over 100Gb), can be set up to backup overnight/weekend + robotic archive + backup systems can swap tapes in + out automatically.

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59
Q

What are the disadvantages of tape streamers?

A

Serial access makes it slow access, need special equipment to record + read data on tape + less robust so can easily break.

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60
Q

Describe magnetic disks.

A

Random/direct access. Divided into circular tracks which are subdivided by sectors into blocks. The outside track contains an index which holds track + sector location for each saved file. May have multiple disks (several platters on the same spindle). Data can be written on both sides which have a read/write head each that are fixed together so all read the same track on their surface at the same time.

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61
Q

What is random/direct access?

A

Any piece of data on a disk can be accessed without having to go through all the information stored before it on that disk.

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62
Q

How is access time worked out?

A

Access Time = Seek Time + Rotational Delay + Transfer Time

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63
Q

What is seek time?

A

The time it takes to move the read/write head to the correct track on the disk.

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64
Q

What is rotational delay?

A

The time it takes to rotate the disk so that the read/write head is at the correct block.

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65
Q

What is transfer time?

A

The time it takes to read the data and transfer it to the computer’s primary memory.

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66
Q

What is a cylinder of data?

A

It’s faster for the computer to write data that doesn’t fit on one track on one surface onto the same track on a different surface rather than moving the read/write head to the 7th track.

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67
Q

What is the speed of a hard disk?
What is transfer time?
What is seek time?

A

7200 RPM/5400 RPM/15000 RPM.
70 Mb/SV
9ms

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68
Q

How does a magnetic disk work?

A

The heads don’t physically touch the disk but float above it. The distance determines how well the data can be read + so affects the capacity of the disk. This is why manufacturers are trying to reduce the float/flying height of read/write heads. Stores data on mylar film coated with iron oxide.

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69
Q

What is the float height of modern read/write heads? What is the human hair in comparison?

A

13 nanometers. 5100 nanometers.

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70
Q

What is a head crash?

A

When the read/write head is too close to the surface of the platter and touches the disk, it permanently damages the disk and the read/write head so the disk won’t work.

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71
Q

What are the advantages of magnetic disks?

A

Necessary to support the way the computer works, large capacity, store + retrieve data faster than floppy disk/CD/DVD, non-volatile, cheap per Mb.

72
Q

What are the disadvantages of magnetic disks

A

Slower than ROM/RAM chips, head crashes, regular crashes lead to loss of data + disk is fixed inside PC so cannot be transferred to another computer.

73
Q

What is an optical disk?

A

A disk which can be written to and read from using a laser.

74
Q

Give 3 examples of WORM optical storage devices and describe WORM. What are they used for?

A

CD-ROM, DVD, Blu-Ray.
Write Once, Read Many.
Distributing software + multimedia products.

75
Q

Describe how the speed measurement works in optical storage devices?

A

E.g. x48 or x12. Their max operating speed is 48 or 12 times the speed of a 1x drive. For CDs, 1x is the speed to play audio at 153.6Kb/s and for DVDs to play video it is 1.32 Mb/s.

76
Q

Optical storage devices which also write have more than one speed rating, what does it refer to?
What do CD-RW drives also have?

A

The maximum write speed which is very different to the read speed.
Minimum reliable write speeds.

77
Q

Describe CD-ROMs.

A

Capacity of 700MB. (74 Minutes of audio on a standard CD player or more if a different encoding method is used)

78
Q

Describe the structure of a CD-ROM.

A

Has 3 layers: plastic, reflective aluminium + acrylic. When it’s made, the plastic layer is moulded to create microscopic bumps (pits) which represent data. Flat = 1, bump = 0. These bumps form a single spiral around the disk. The label is printed on the acrylic layer.

79
Q

How is a CD-ROM read from?

A

CD player focuses a laser on the spiral; light bounces back from reflective layer + is detected by a sensor. The laser follows the spiral track from the centre to the outside so the spinning speed has to be reduced as the laser moves outward as the bump speed must be stable.

80
Q

What is the typical data transfer rate of a 20x CD drive?

A

3 Mb/s.

81
Q

What is the structure of a CD-R disk compared to a CD-ROM?

A

They have an extra layer of dye between the plastic and the reflective layer. On a new CD-R disk, the laser can shine through the dye and bounce back off the reflective layer.

82
Q

How does the CD Recorder work?

A

It has an extra burning laser that is much more powerful than the reading laser which heats up the dye and makes it non-reflective, the equivalent of a bump on the spiral. This permanently changes the dye and the disk can then be read by both CD-R drives and ordinary CD drives.

83
Q

How does a CD-RW work?

A

Similar to a CD-R. The dye layer is replaced by a phase-change layer with surrounding dielectric layers, when it’s heated to a certain temp it becomes liquid which doesn’t reflect light. When heated to another temp, it returns to a solid which is transparent and allows light to pass through so they can be erase and re-written. They are also slightly less stable than CD-Rs so less suited to long term storage. Multi-phase alloy.

84
Q

Describe the structure of a DVD.

A

The tracks are 0.32 microns wide and 0.74 apart, each pit is 0.4 microns long so a spiral is over 12km long. Can be dual layer so they have 2 sets of data on each side of the DVD. Stores 4.7 GB.

85
Q

What are the measurements of a CD?

A

Track is 0.5 microns wide, 1.6 apart.

86
Q

What is the data transfer rate of a 16x speed DVD player?

A

21.13 Mb/s

87
Q

How is the storage of a Blu-Ray achieved?

A

Sony’s version of high def disks. Single layer can hold 27 GB. Dual can hold 54 GB. It uses a blue laser which has a shorter wavelength so can be focused more accurately. Allows extra features to be included in software/multimedia applications that are stored. Allow to skip to any spot on disk instantly and record HD TV without quality loss + access web to download subtitles + features.

88
Q

What are the advantages of CD-R/ROM-RW?

A

Small, portable, cheap, most computers can read them, fairly fast access.

89
Q

What are the disadvantages of CD-R/ROM-RW?

A

Fairy fragile, smaller capacity than hard drive/DVD + slower access than hard disk.

90
Q

How much can a DVD store?

A

Single layer = 4.7 GB.

Dual layer = 9 GB+

91
Q

What are the advantages of DVDs?

A

Large storage, sound + picture quality is excellent, mass produced so cheap, DVD players can read CDs.

92
Q

What are the disadvantages of DVDs?

A

DVDs don’t work in CD drives, no single standard of DVD + easily damaged.

93
Q

Storage capacity of Blu-Ray?
What can play them?
Use?
Name?

A

Single = 25 GB, Dual = 50 GB.
Blu-Ray player.
High quality commercial movies or own burner.
Uses blue laser.

94
Q

What are the advantages of Blu-Ray?

A

Very large storage + can store a full length high definition films.

95
Q

What are the disadvantages of Blu-Ray?

A

Need dedicated player + loading a film can take minutes as so much data must be read.

96
Q

What is flash memory?

A

Type of solid state memory which has no moving parts. Type of EEPROM memory and uses logic gates to represent 1s and 0s. Covers all kinds of storage devices which use similar technologies to store data. Uses transistors which have 3 main components, the source, the drain and the gate/control gate.

97
Q

Give examples of flash memory?

A

SD cards, xD cards, memory stick, CompactFlash, microSD. Games consoles + laptops are beginning to use flash but much smaller in size.

98
Q

What are the advantages of flash memory?

A

More compact + portable, more storage than CD, reliable as they have no moving parts, easily branded to reflect organisation + not affected by magnetic fields.

99
Q

What are the disadvantages of flash memory?

A

More expensive than CD/DVD, easily lost + metal part which is inserted into USB port can be snapped off/damaged.

100
Q

How might the type of user interface be chosen?

A

End user’s expertise, hardware used + purpose of software.

101
Q

What is a GUI?

A

Graphical User Interface. Provides you with functionality to create + manage windows used on screen. Also provides with features such as icons on desktops which rep apps, buttons + scrollbars. Allows to choose from menu, mouse position is indicated on screen by a pointer.

102
Q

Give the basic 4 items in a GUI?

A

WIMPs.

Windows, Icons, Menus + Pointers.

103
Q

What are the advantages of a GUI?

A

Don’t need to learn a complex set of instructions, commands replaced by icons which can be selected by a pointer which is faster, more than one program can be run at a time, layout is consistent allowing user to transfer skills, only valid options made available with icons/menus + online help available so all skill levels can find out how to use new features without expensive training.

104
Q

What are the disadvantages of a GUI?

A

Use lots of RAM/backing store as graphics need to be stored, longer to load as icon must be interpreted, require more powerful processor + better graphics + slow for experienced programmers.

105
Q

What different user interfaces are there?

A

GUI, forms + CLI.

106
Q

How do forms work as a user interface?

A

Method of enabling you to interact with an application, provides limited choices as to the use, Can set text characteristics or interact with the system software or enter data into a system.

107
Q

What are the advantages of Forms?

A

Easy to program, easy for user to see options available, data validation can be used on data entry forms, fast to enter data by making choices, little training required + don’t need much processing power/memory.

108
Q

What are the disadvantages of Forms?

A

Only limited options presented, visually impaired people may have trouble seeing text/options + not good for highly complex applications (e.g. tax form)

109
Q

How does a CLI work as a user interface?

A

Command Line Interface e.g. DOS operating system.
Allows user to interact directly with computer system by typing in commands into a screen. Can’t just type in any type of instruction, just a few specific ones.

110
Q

What do many commands in CLI have?

A

Switches, extra parameters/flags which add extra functionality to the command.

111
Q

What are the advantages of CLI?

A

If user knows correct commands then it can be faster, doesn’t use as much CPU processing time as others, doesn’t require Windows to run, low resolution, cheaper monitor can be used + needs less memory.

112
Q

What are the disadvantages of CLI?

A

Can be confusing for first timers, if mistyped instruction you may need to restart, can’t just guess an instruction, commands must be typed exactly + large number of commands must be learned.

113
Q

WIMP:
Applications
Advantages
Disadvantages

A

Suitable for less experienced user.
Intuitive + provides user with familiar approach to carry out commands.
Complex interfaces require extensive resources (RAM/Processing power) for effective operation.

114
Q

CLI:
Applications
Advantages
Disadvantages

A

Suitable for experienced users who must max processing capabilities of computer.
Min resources required (RAM/Processing power) to display interface to end user.
Users must be familiar with syntax.

115
Q

Forms Dialogue:
Applications
Advantages
Disadvantages

A

Suitable for use when entering data into database or when completing task using wizard application.
Supports user through data entry process + ensures end user can enter data required to complete task.
Limits data entry options available to user as data entry is closed caption + no open response available.

116
Q

How might we enter text into digital devices?

A

QWERTY keyboard (letters/digits/special characters), some have a separate numeric keyboard, ASCII is common character set.

117
Q

How does ASCII work?

A

American Standard Code for Information Interchange. Uses 7 bits, giving 32 control codes + 96 displayable characters/symbols. Eighth bit used for error checking.

118
Q

What does the depression/selection of a key on a device do?

A

Generates digital signal representing character code. When symbol representing certain character is to be printed/displayed on the screen of a particular device, the character code is converted into the appropriate symbol.

119
Q

How might sound be input into digital devices?

A

Simple microphones.

120
Q

How does sound input work through microphones?

A

Sound is produced by vibration of air so it is an analogue format. Electrical output from microphone. Sound sampling is used as the analogue must be converted into digital.

121
Q

What is analogue format?

A

Continuously varying signal. The same a microphone’s output as it is also continuously varying in the form of voltage.

122
Q

What is sound sampling?

A

Special hardware (ADC) measures the level of the sound many times and then records this as a numerical value.

123
Q

How might video be input into digital devices?

A

Digital video camera: camera (image capturing component) + recorder (stores captured video images) Image is recorded using digital camera and transmitted into computer pixels which are stored in whatever media storage is available.

124
Q

What does the CPU contain?

A

Electronic chip on motherboard, consists of transistors. Role is to fetch instructions from RAM, decodes + executes them enabling it to process data + make decisions. Contains ALU, CU + Registers. CU controls how data moves around CPU + monitors input/ouput devices.

125
Q

If more data needs to be stored other than the registers. what is used?

A

Memory

126
Q

What 5 registers are involved in the Fetch-Execute cycle?

A

MAR, MDR, IR, ACC + PC.

127
Q

Can more than 1 program run in main memory?

A

Yes

128
Q

Give the basic flow of instructions throughout the fetch operation.

A

Program loaded into RAM, starting address into PC, copied into MAR, CU loads address onto address bus + sends signal to main memory to read address, instruction passed across data bus and copied into MDR which is copied into IR for decoding. PC incremented by 1 to begin next cycle;

129
Q

What takes place during the decode operation?

A

Takes place in CIR, CU reads IR, ensures it can carry out + checks against internal instruction set. If invalid, error flagged.

130
Q

What takes place during the execute operation?

A

Instruction carried out using accumulator + result stored in register.

131
Q

What are the instructions used to boot a computer?

A

BIOS

132
Q

What is paging?

A

Process used to transfer bits of program to and from backing store if whole program is too big to fit in computer’s RAM.

133
Q

What is EEPROM?

A

Electronically Erasable Programmable Read Only Memory

134
Q

What is EEROM?

A

Electrically Erasable Read Only Memory

135
Q

What is EPROM?

A

Erasable Programmable Read Only Memory

136
Q

What does each disk have on their first track?

A

An index

137
Q

What is each track on a disk split up into?

A

Blocks

138
Q

What is a sector?

A

Pie shaped part of a magnetic disk.

139
Q

What type of file access is used in magnetic tape?

A

Sequential

140
Q

Internal Hard Disk:

Physical size, cost, capacity, access speed, portability, durability, reliability + typical use.

A

3.5 inches, 3 TB for £85, up to 6 TB, 3 Gb/s, not portable (built in), good when not in use but vulnerable when spinning, can write infinite number of times, affected by heat + magnetic fields. V. reliable. Inside PC as secondary storage.

141
Q

Portable Hard Disk:

Physical size, cost, capacity, access speed, portability, durability, reliability + typical use.

A

2.5 inches, 3 TB for £85, up to 649 GB, 480Mb/s, can fit in large pocket, good when not in use but vulnerable when spinning, can write infinite number of times, affected by heat + magnetic fields. V. reliable. Supplementary storage for PC or portable storage when high capacity necessary.

142
Q

What is the speed of a USB3 Interface?

A

480 Mb/s

143
Q

Internal Solid State/Flash Storage:

Cost, capacity, access speed, portability, durability, reliability + typical use.

A

128 GB for £40/960 GB for £200, 128 GB to 2 TB, 6 Gb/s, not portable (built in), more robust than moving (5-10 times more durable than hard disk), v.reliable. Notebooks, tablets, slim laptops.

144
Q

USB Memory Stick:

Cost, capacity, access speed, portability, durability, reliability + typical use.

A

32 GB for £15/128GB for £35, 16 MB to 256 GB, 480 Mb/s, very portable (keyring/pocket), very durable (some easily snapped), very reliable but can corrupt if removed too soon. Personal use moving files between computers.

145
Q

Memory Card:

Cost, capacity, access speed, portability, durability, reliability + typical use.

A

128 GB SD card £25, 2 GB to 128 GB, Depends on type + interface, very small + designed for portable devices, very durable (not sensitive to knocks/temp), very reliable. Phones + cameras.

146
Q

CDs:

Cost, capacity, access speed, portability, durability, reliability + typical use.

A

700 MB CD-R 7p, 640 MB, up to 7Mb/s (52x), easy to carry in large pocket/bag, depends on how stored as quality degrades but average is 10-25 years, affected by prolonged sunlight, good for a while but degrades over time, CD-ROM for software distribution, CD-R/RW for backup/archive.

147
Q

DVDs:

Cost, capacity, access speed, portability, durability, reliability + typical use.

A

7.4 GB DVD-R 24p, 4.7gb to 8.5GB (1/2 layers), 16 Mb/s (12x), easy to carry in large pocket/bag, depends on how stored as quality degrades but average is 10-25 years, affected by prolonged sunlight, good for a while but degrades over time. Backup + distribution of software/games/movies.

148
Q

Blu-Ray:

Cost, capacity, access speed, portability, durability, reliability + typical use.

A

25 GB 44p, 25 GB to 50 GB (1/2 layer), 50 Mb/s (20x), easy to carry in large pocket/bag, depends on how stored as quality degrades but average is 20-100 years, good for a while but degrades over time. Store movies/games + backup.

149
Q

ADC

A

Analogue to Digital Converter

150
Q

DAC

A

Digital to Analogue Converter

151
Q

Describe the main features of CLI?

A

Single word commands from a short list of commands entered into prompt. Switch/parameters may be required.

152
Q

What is sample rate?

A

The number of audio samples carried per second (frequency)

153
Q

What is the sample rate of an audio CD?

A

44.1kHz

154
Q

What is bit depth?

A

Number of bits of info in each sound clip

155
Q

What is bit rate?

A

Bit rate of a file tells us how many bits of data are processed every second.

156
Q

How do you calculate bit rate?

A

Bit Rate = Sample Rate x Bit Depth x No. of channels

157
Q

What does a higher sample rate, bit depth and bit rate result in?
What if the audio file is compressed?

A

Higher quality sound + larger storage requirement.

Decrease in sample rate, bit depth, bit rate and quality.

158
Q

What is a buffer?

A

Type of temporary storage which holds streaming sections of video file to ensure constant feedback. e.g. streaming movie stored in RAM.

159
Q

What is an example of a compressed audio file?

A

mp3

160
Q

WIMP:

Windows

A

Allow the user to have more than one tab/application open.

161
Q

WIMP:

Icons

A

Represent each program/application and are clickable allowing user to open application with ease

162
Q

WIMP:

Menus

A

Give options to click on for different commands/operations. May also offer shortcuts

163
Q

WIMP:

Pointers

A

Shows where mouse is on the screen

164
Q

What is resolution?

A

Number of pixels that can present an image on the screen. Higher resolution means higher quality.

165
Q

What is the purpose of a USB port on any computer?

A

Connect external devices e.g. keyboard/flash drive. Could even charge your phone.

166
Q

What is the purpose of having 2GB of RAM?

A

2GB of internal memory to store program currently being executed + data currently being used.

167
Q

What is hardware?

A

Any physical device that makes up part of or plugs into your computer. You can see it, touch it & pick it up.

168
Q

What is software?

A

Programs/applications that allow the performance of various tasks.

169
Q

What are the 2 main types of computer software?

A

System software + application software

170
Q

What is system software?

A

Operating system + utility programs which control how computer hardware works.

171
Q

What is application software?

A

Common programs you use daily. e.g. word, excel, access, email programs, web browsers + anti-virus software.

172
Q

What is tunneling?

A

The data can be erased off flash drive by applying negative charge to transistor to make trapped electricity drain back down away from floating gate.

173
Q

What is a bus?

A

A set of physical connections/cables/circuits used to connect various hardware components to execute instructions.

174
Q

What is the purpose of the clock?

A

Synchronises all internal processes by generating pulses at a constant rate.

175
Q

Explain the difference between internal memory and secondary storage.

A

SS is backup storage which can usually be removed from computer e.g. CD/DVD. Ensures if internal is damaged, there is a safe copy of data. Internal is primary copy, not removable e.g. RAM/cache.

176
Q

How can the processing speed of a PC be improved?

A

More RAM as it’s close to CPU so increases speed. Add more cores so more instructions executed at same times as tasks are shared out so increase speed.

CCEA AS Digital Technology (9 decks)

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