1.1 Architecture Flashcards

1
Q

What is another term for the CPU?

A

Microprocessor

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2
Q

What is software?

A

Software is a computer program that contains the set of instructions needed by the CPU in order to perform a specific task.

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3
Q

What is the difference between system software and application software?

A
  • System software contains programs that manage the operation of the computer
  • Application sofware are programs written for a specific purpose (word processing application, photo editor)
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4
Q

List three input devices

A
  • Keyboard
  • Mouse
  • Touch screen
  • Microphone
  • Heat sensor
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5
Q

List three output devices

A
  • Computer Moniter
  • Printer
  • Speakers
  • Led light
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6
Q

Are headphones an example of an input device, an output device, or neither?

A

Neither, they are an accessory.

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7
Q

What is an embedded computer?

A

An embedded computer is a computer that is designed with a specific task in mind. All parts and components are usually built on a single printed circuit board.

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8
Q

List three benefits of using an embedded computer

A
  • Small –> less space needed inside the equipment.
  • Printed on a single printed circuit board –> much easier to replace if it breaks down
  • Cheaper to produce than general purpose computers –> Overall cost of equipment in which it is embedded is reduced
  • More reliable and robust that a general purpose computer –> no moving parts so they are less likely to stop working.
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9
Q

List 2 concerns associated with embedded computers

A
  • If it goes wrong its likely the equipment itself with stop working
  • Requires specialist skills to design them
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10
Q

What is a bus?

A

A bus is a set of wires or tracks laid down on a printed circuit board (to move data around).

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11
Q

Inside a 32 bit computer, how many tracks will each data bus have?

A

32

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12
Q

Name the three types of bus

A
  • Data Bus
  • Address Bus
  • Control Bus
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13
Q

What does the data bus do?

A

Carries the actual data around the system.

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14
Q

What does the address bus do?

A

Carries information on where the data needs to go or come from.

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15
Q

What does the control bus do?

A

Carries singals around the system to control various components (such as the DVD drive, hard disk or graphics card).

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16
Q

What does the CPU do?

A

The CPU fetches instructions from memory (RAM), it decodes the instructions and then executes those instructions.

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17
Q

On a desk top computer, where is the CPU normally located?

A

On the motherboard.

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18
Q

Name the three sections inside the CPU

A
  • Control Unit
  • Arithmetic Logic Unit (ALU)
  • Registers
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19
Q

What are the three main jobs of the control unit?

A
  1. It controls the way data moves around the CPU (timing signals)
  2. It executes the instructions provided by the program (control signals)
  3. It controls and monitors the flow of data between the CPU and other components (signals to memory/devices)
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20
Q

What is the job of the ALU?

A

Handles arithmetic operations and logic operations.

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21
Q

What are registers used for?

A

Registers are used to hold temporary data while a software program is running.

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22
Q

Why are registers used?

A
  • It is much faster to shift data to and from the registers rather than in and out of the Cache or RAM
  • So this speeds up the processing time.
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23
Q

Describe the relationship between memory capacity and speed.

A

As memory capacity increases, speed decreases (or vice versa)

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24
Q

What is cache memory used for?

A
  • Cache is a very fast but small type of RAM
  • Cache memory is used to store instructions or data that are either frequently used, have recently been used or are about to be used.
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25
Q

Which level of cache is the fastest?

A

Level 1 (Internal CPU cache)

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26
Q

What is a CPU clock?

A

The clock is a tiny quartz crystal inside the CPU chip that ‘ticks’ at a steady speed.

27
Q

What is the clock speed for a typical computer?

A

3GHz (three billion instructions can be processed each second)

28
Q

What is Von Neumann architecture?

A

Von Neumann architecture is where both the data and software that are currently being used are stored in RAM

29
Q

What is another name for a computer that uses the Von Neumann archiceture?

A

A stored program computer.

30
Q

What are 6 features of Von Neumann architecutre?

A
  • Enough memory to hold both programs and data - easy to change task by loading a different program
  • Control Unit - handles movement of instructions and data around the computer
  • Buses to carry instructions and data
  • ALU
  • Special type of memory called REGISTERS that do specific jobs
  • A way of inputting and outputting data
31
Q

What is an alternative to Von Neumann architecture and why is it less popular?

A
  • Harvard Archiceture
  • Keeps data and instructions in seperate memory
  • Disadvantages such as cost and complexity
32
Q

What is the role of the MDR?

A

The memory data register is where all instructions and data are TEMPORARILY stored on their way to the CPU OR RAM.

33
Q

What is the role of the MAR?

A

The address of the data or instruction being accessed is temporarily stored in the Memory Address Register.

34
Q

What is the role of the program counter?

A
  • As each instruction is processed, the program is updated with the adress of the next instruction to fetch.
  • The program counter passes this next address to the MAR.
35
Q

What is a branch instruction?

A

When the program counter is instructed to jump to a completely different adress (rather than one location higher than the current one).

36
Q

What is the role of the accumulator?

A

The accumulator is used to temporarily store data whilst calculations are being performed within the ALU.

37
Q

Why do accumulators mean the program runs faster? (4)

A
  • The accumulator is a register
  • Registers are the fastest type of memory
  • Without an accumulator, data would have to be stored in RAM
  • Which is much slower to access
38
Q

Why do modern CPUs have lots of extra general purpose processors?

A

• To make programs more effiecient than having a single register needing to contain every temporary data item.

39
Q

Put these operations in the right order:

Decode, Excecute, Fetch

A

Fetch , Decode , Excecute

40
Q

Name the registers used in the fetch decode excecute cycle.

A
  • Memory Data Register (MDR)
  • Memory Adress Regiester (MAR)
  • Program Counter
  • Accumulator
  • Instruction Register
41
Q

What is the fetch operation responsible for?

A

The fetch operation is responsible for getting an instruction or data from main memory into the CPU.

42
Q

True or False? All programs start at location 0.

A

False. Programs could start at any location in main memory (e.g. 305)

43
Q

Describe the states of the fetch operation.

6 parts in detail

A
  • The Program Counter has been pre-loaded with the starting address of the first instruction within the program
  • The program counter value is copied into the MAR
  • Once the MAR is loaded, the Control Unit loads the address on to the address bus and also sends a signal to main memory to read the instruction contained at that address.
  • Now the instruction is passed across the data bus and copied into the Memory Data Register.
  • Then the instruction in the MDR is copied into the Instruction Register so that it is ready to use during the next stage (decode)
  • The program counter is now incremented by one location so that it is ready to begin the next fetch cycle.
44
Q

What happens during the ‘decode’ stage?

A

The CONTROL UNIT reads the Instruction Register and makes sure that it can carry out the instruction (that it’s in its INSTRUCTION SET).

45
Q

What would happen if the program had been corrupted and the control unit did not recognise the instruction?

A
  • It would flag an error

* Or more likely crash the program

46
Q

What happens during the ‘excecute stage’?

A

The decoded instruction is carried out.

47
Q

True or False? All instructions are excecuted within the accumulator.

A

False, there are other registers than can be used.

48
Q

Name the factors that affect CPU performance.

A
  • Clock
  • Cores
  • Cache (Internal and external)
  • Size of RAM
  • Graphics Card (GPU)
49
Q

How does clock speed affect CPU performance?

A

The higher the clock frequency, the faster the CPU can run and the more instructions that can be processed every second.

50
Q

Why do clocks have a maximum speed? (3)

A
  • Every tick, a bit of power is used
  • Which causes heat to be generated
  • If you go too high, the heat will damage the chip itself
51
Q

What does a heat sink do? Mention its role and its placement in your answer.

A
  • A heat sink is takes heat away from the CPU, keeping temperature to a minimum and stopping damage to the CPU.
  • It is placed on top of the CPU and is joined with heat-conducting paste
52
Q

What is overclocking and what does overclocking require?

A

Overclocking is making a CPU run faster than its normal design speed.

It requires more advanced cooling systems (e.g. a water cooled system)

53
Q

What is a core?

A

A core in a complete processing unit within the CPU - containing and ALU, Control Unit and Registers

54
Q

What is the name for a CPU with:
• Two cores
• Four cores

A
  • Dual core

* Quad-core

55
Q

What is multitasking?

A

Multitasking is the ability for the CPU to carry out two or more tasks simultaneously.

56
Q

What is parallel processing?

A

Parallel processing is when a single task (program) is split into two or more parts and each part is processed at the same time.

57
Q

Why do you not always get twice the performance while parallel processing?

A
  • Many programs cannot be split neatly into two independent parts
  • Because they are mostly sequential (each task depends on the outcome of a previous task so it has to wait for the first task to be completed)
58
Q

Explain how cache size affects CPU performance.

A

Having a larger cache will speed up processing because the CPU can access data and instructions faster than they can from RAM.

59
Q

Explain why cache is limited in size in a computer

A

Cache is more expensive than RAM so a balance is needed between performance and cost.

60
Q

Explain the effect of installing more RAM than needed on computer performance.

A

There is hardly any improvement in performance because the extra RAM goes unused.

61
Q

Explain the effect of having insufficient RAM on computer performance.

A
  • Virtual memory will be used to store some of the currently running programs if RAM is full.
  • Virtual memory is very slow compared to RAM
  • The computer will seem to be running very slowly
62
Q

Explain how graphics cards affect CPU performance. (3)

A
  • GPU is designed to handle graphics and images much faster than the CPU
  • If an application is making intense use of graphics or video then installing a GPU will improve performance considerably.
  • CPU will send any graphics related tasks directly to GPU
63
Q

List 4 issues with graphics cards.

A
  • Expensive
  • Don’t improve CPU performance on all tasks
  • Use a lot of power -> computer may need more powerful power supply -> further cost
  • Require a cooling fan -> makes computer louder than before