1.1.1 Structure and Function of Processor Flashcards

1
Q

CPU’s job?

A

cpu processes data and instructions. cpu is where all searching,calculating,sorting and decision making takes place

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2
Q

what does the CU stand for?

A

Control Unit

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3
Q

function of the CU?

A

to manage execution of instructions.

controls and monitors hardware
controls input and output of data(so signals go to the right place at the right time)
controls flow of data in CPU

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4
Q

what is used for signal sending ?

A

buses

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5
Q

what is the ALU responsible for ?

A

responsible for performing mathematical calculations and logic operations. Also it acts as a gateway to processor

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6
Q

where are results from ALU stored?

A

accumulator

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7
Q

what is a register ?

A

a high speed storage area in the CPU used for instruction processing

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8
Q

what are the 5 registers ?

A
PC 
MAR 
MDR 
CIR 
ACC
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9
Q

what does CIR stand for ?

A

current instruction register

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10
Q

role of the PC (program counter)

A

contains address of the next instruction to be executed

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11
Q

function of MAR

A

stores memory address from which data will be fetched or sent and stored

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12
Q

function of MDR

A

stores data being transferred to and from access storage

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13
Q

function of CIR

A

contains information specifying the instruction tags being or about to be performed

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14
Q

function of ACC

A

stores ALU calculations

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15
Q

what are buses ?

A

pathways used to send data around the processor

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16
Q

what are the 3 main buses ?

A

control
data
address

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17
Q

characteristics of a control bus

A

it is used by CPU to communicate with other devices and components carrying commands and returning status signals

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18
Q

characteristics of a data bus

A

carries data/information from one register to the other between the processor and the memory

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19
Q

characteristics of an address bus

A

carries the address of the memory location being read or written to

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20
Q

what bus would be used between the CPU and main memory when MAR needs the instruction address

A

address bus

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21
Q

what bus would be used to get the instruction data to MDR from main memory

A

a data bus

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22
Q

what bus would be used between acc and the main memory after instruction execution

A

control bus

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23
Q

FETCH

A
PC holds address of next instruction. 
Address is copied to MAR 
Location is sent down address bus and fetch signal is sent by control bus 
Contents from memory go to processor 
Contents in MDR and then copied to CIR 
PC increments by 1
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24
Q

DECODE

A

CIR contents go to control unit
CU does the decoding.
- it also checks against set of instructions in ROM within CPU
Check is preformed to make sure data is present for current instruction (in MDR)

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25
Q

EXECUTE

A

Instruction address copied from CIR to MAR
Processor carries out instruction.
Return result into L1 data cache.
Results sent to RAM

26
Q

Factors affecting CPU performance

A

Processor Clock Speed
Amount of Cache Available
Number of cote processors

27
Q

Describe clock speed

A

signal synchronising process by switching between 0 and 1 at a fixed rate measured in Hz

Higher clock speed means more instructions can be executed per second

28
Q

describe cache memory

A

a high performance RAM,stores data waiting to be processed by CPU. Usually built into processor to minimise access time

29
Q

what is L1 cache ?

A

cache that’s a part of the CPU. It is the smallest but the fastest to access (between 8 and 64 kb)

30
Q

what is an L2/L3 cache ?

A

extra cache built in between CPU and RAM. they have a longer access time but a larger capacity

31
Q

describe multi core

A

a greater number of cores so instructions can be executed simultaneously

32
Q

advantages of underclocking

A

less power consumption also battery lasts longer
heat generation is lower so less damage risk
this means a fan can be removed making the machine work silently

33
Q

advantages of overclocking

A

increased CPU performance so demanding applications work faster and smoother

34
Q

dangers of overclocking?

A

increased power consumption and heat generation and therefore increased risk of catching fire or causing heat damage

this would mean warranty is void

35
Q

ROM characteristics

A
data can’t be deleted or altered. 
non-volatile 
read only 
1 or 2 mb 
used to boot up systems  
contains BIOS
36
Q

what does BIOS stand for ?

A

basic input output system

37
Q

what are BIOS?

A

Its a bootup program that checks computer’s functionality. It performs check using bootup loader and gives control to the OS.

38
Q

characteristics of RAM

A
OS needs to be loaded into it for it to run 
stores working and opened programs 
can be accessed and changed at any time
volatile 
usually 8GB
39
Q

what does ROM and RAM stand for ?

A

read only memory.

random access memory

40
Q

characteristics of virtual memory

A

part of the hard drive that is used as a RAM extension
memory is divided into physical units known as PAGING
used when RAM is full to keep wanted programs opened
data is stored temporarily and needs to be copied to RAM before it can be used again

41
Q

what is PAGING

A

it’s when the memory is divided into physical units

42
Q

what is DISK THRASHING

A

having to move data between hard disk and RAM slowing down your machine

43
Q

is a sensor an input or output device ?

A

input

44
Q

printer types ?

A

laser, thermal,plotter

45
Q

2 pieces of primary memory ?

A

RAM and ROM

46
Q

Primary memory ?

A

can be accessed directly by CPU

47
Q

What are the other 2 factors affecting processor performance?

A

Width of the bus

48
Q

What is the width of the bus and how does it affect processor speed?

A

The amount of data the processing unit can transmit at a time. The data is called words and it is an amount of bits that are addressed.

49
Q

What are some common input devices?

A

BARCODE READER - bars and spaces represent characters in a code when they’re scanned.The laser light is either absorbed or reflected.
RFID - uses numbers to obtain details in a computer database

50
Q

What does pipelining allow ?

A

Allows the processor to handle more than one instruction at a time but each in a different part of the fetch-d-execute cycle.

51
Q

What does pipelining require ?

A

A RISC structure to allow different circuitry to handle the fetch-decode-execute cycle. Also requires a Harvard Architecture..

52
Q

What is pipelining?

A

The next instruction execution process is started before the previous is fully finished.

53
Q

What is a John Von Neumann Architecture?

A

A processor architecture where memory is used to store both programs and data together.This uses the fetch-decode-execute cycle and works therefore one instruction at a time.

54
Q

Where is the John Von Neumann Architecture used?

A

Desktop Computers
Laptops
Workstations
High Performance Computers

55
Q

What is the Harvard Architecture?

A

A processor in which there is a separate memory for data and programs/instructions.it utilizes the CU right in the middle of the structure.

56
Q

Why can pipelining be used within a Harvard Architecture?

A

Since there is seperate buses and memory for data and instructions. This means that the CPU is capable of reading and fetching at the same time.

57
Q

Why can’t we use pipelining with the Von Neumann Architecture?

A

Since there is only one bus so it isnt able to fetch instructions at the same time as data is sent. This si known as bottleneck.

58
Q

How many cycles does it take for Von Neumann and Harvard Architecture to carry out instructions.

A

Von Neumann - 2 clock cycles

Harvard - 1 clock cycle

59
Q

Where is Harvard Architecture used?

A

Embedded Systems

DSP (signal processing)

60
Q

What is bottleneck in Von Neumann Architecture?

A

Delay of transmission of data through a microprocessor or TCP/IP network. The throughput of a computer system is limited due to there being only one bus.