Computer science revision

Fetch stage

next instruction fetched from RAM

instruction brought back to CPU

Decode stage

Cpu works out what is required from intrsuction

execute

CPU carries out instruction, and stores result in RAM.

2 differences between RAM and ROM

RAM:

read on write

volatile

ROM:

read only

non-volatile (stores data even after computer switches off)

how does larger clock speed influence computer

Faster clock speed = more number of instructions processed and executed per second

how does larger cache size affect computer

larger cache size = larger memory unit directly next to CPU, makes computer quicker as takes less time to travel to cache than to RAM.

How does number of core processors affect computer

More number of core processors, more number of F-E cycles can be executed at the same time.

what is the ALU

Arithmetic logic unit
performs calculations and logical decisions

what is CU

Control Unit

co-ordinates how data moves around CPU

decodes instructions fetched from CPU

what is clock

keeps all components in CPU in-sync with each other by generating regular pulses.

what is Bus

Bus is collection of wires through which data is transmitted from one compound to another.

registers

small fast memory in CPU.Registers hold data temporarily for quick access by the CPU during processing tasks.

4 types of registers

ACC: Accumulator

MAR: Memory Address register

MDR: memory data register

PC: program counter

ACC

stores result of ALU

MAR

stores address of next instruction to be fetched from RAM

MDR

stores data received from RAM

PC

stores address of next instruction to be executedin a computer's memory. C

CPU

Central processing unit that executes instructions in a computer system. Executes F-E cycles

embedded systems

system with dedicated function inside larger unitex

examples of embedded systems

washing machine

dishwasher

coffer machine

traffic light

why do computers use binary

CPU is made of transistors which only be on or off. the 1 represents on, 0 is off.

limitations of ASCII

only represents english alphabet, numbers and some special characters. no other language than english.

what is hardwear

Hardware refers to the physical components of a computer system.

hardwear in the computer

CPU, RAM, storage devices, keyboard and mouse.

softwear

controls the hardwear.

examples of softwear

application softwear

gaming softwear

spreadsheet

social media.

why do you need softwear

additional security, boots up device, manages device

assembler

translates low level language to machine code line by line

compiler

translates high level code directly all in one go.

used when progam is finished

does not need translation softwear

interpreter

translates highlevel code line by line

used when program is being written

translation code needed