1.1 System Architecture Flashcards
(35 cards)
Define general purpose computer
A computer designed to be able to carry out a range of actions and tasks, use multiple applications
Example of applications
Accessing internet, storing and retrieving data, using word processing software
Examples of general purpose computers
Smartphone, smart tablet, gaming consoles, PC
What is the basic computer model?
Input => Process (or storage) => output
Explain the basic computer model
Data is input, processed by the CPU and then either output or sent to secondary storage. Data is sent to primary memory (RAM) whilst being processed.
Examples of input devices
Touchscreen, controller, keypad, mouse
Examples of output devices
Touchscreen, speaker, display
Examples of storage devices
RAM, ROM SSD USB drive, hard disk/drive
Von Neumann Architecture definition
Common organisation of computer where instructions and data are stored in the same memory
explain function and purpose of ALU
- ALU is the arithmetic logic unit
- definition = component of CPU that performs logic and arithmetic calculations
- can do arithmetic (+,-,/,x), binary shifts and logic operations such as AND or NOT
Explain function and purpose of CU
- CU is the control unit
- definition = component of CPU that coordinates CPU activity
- fetches and decodes instructions and data from memory
- sends out control signals that control how data moves around CPU and memory
Explain function and purpose of cache
- definition = a small area of memory near CPU that can be accessed quickly and is used to store frequently used data or instructions
Define fetch-execute cycle
The basic operation of the CPU - it continually fetches, decodes and executes instructions stored in memory
Explain fetch-execute cycle’s fetch section
- each instruction is stored by an address in RAM.
- address copied from PC to MAR
- MAR has address so CU sends control signal to RAM and fetches the data stored at this address
- data from RAM is copied to MDR
- PC is incremented to next instruction’s address
Explain the fetch-execute cycle’s decode section
- MDR contains data or instruction thta was in the address
- this is copied to the CU which decodes the instruction
Explain the fetch-execute cycle’s execute section
- the instruction is executed, which could mean a number of things:
- ALU performs a calculation, accumulator used, incrementing PC
CPU function and purpose
- CPU = central processing unit
- a collection of billions of electronic switches that fetch decode and execute instructions
- purpose =process data and control rest of computer system
- works at high speeds governed by clock chip (vibrating crystal and every tick is one part of FDE cycle)
Define register
A small memory location in CPU where data can be held temporarily and accessed quickly
Define PC
- PC = program counter
- stores the address of the next instruction to be processed
Define MAR
Memory address register - stores the address of the location in memory for data to be fetched from or sent to
Define MDR
Memory data register - stores data fetched from or to be sent to memory
Define ACC
Accumulator - stores results of the calculations carried out by ALU
Name the 3 factors affecting CPU performance
- clock speed
- number of processor cores
- size of cache memory
How does clock speed affect CPU performance?
- measured in GHz (x billion instructions per second)
- it’s number of cycles per second so higher clock speed means that more cycles per second
- CPU performance increases
