1.1- Systems Architecture

Computing pioneer from Hungary who gave his name to a computer architecture that uses stored programs. Instructions are fetched, decoded and executed one at a time.

The phase of the instruction cycle that retrieves an instruction from main memory

This phase of the instruction cycle determines what task the CPU must perform

The phase of the instruction cycle wherebthe task is carried out, which could be an arithmetic shift, logic or memory operation

Also known as the instruction cycle, the complete process of retrieving an instruction from store, decoding it and carrying it out

A single operation, one of these is executed each time the CPU performs the fetch-execute cycle

Also known as RAM or Primary Storage, this is where data and instructions are stored in the Von Neumann architecture

Computers take input, and produce output. This is what happens in between, which needs a CPU

Von Neumann invented this concept, it means keeping the instructions in memory instead of inputting them each time through switches or paper tape

This component repeatedly fetches, decodes and executes instructions. Often abbreviated to CPU

The design of a computer, including the way its components are organised and the rules that male them work together. Von Neumann invented a type of this

• Location address in memory of the next piece of data or instruction to be fetched or stored

A register that stores the data being sent to or retrieved from memory. This could be data to be processed, or an instruction being fetched.

A register in the ALU that holds data temporarily. It stores the results of calculations and logical operations.

• Continuously provides the CPU with the memory address of the next instruction in the cycle to be fetched.

The collection of tiny areas of extremely fast memory located in the CPU, each with a specific purpose, where data or control information is stored temporarily. Examples are the MAR, MDR, PC and Accumulator

A small amount of fast memory in the CPU. It stores the data and instructions most likely to be needed again and it is faster to access than RAM

• Where calculations are carried out • These include: mathematical tasks, logic tests, data comparisons

Any of three communication pathways between the CPU and RAM in the Von Neumann architecture. There is one for addresses, one for data and one for control signals

Component of the CPU which controls the flow of data around the CPU, communication between the CPU and input and output devices, and decodes and executes instructions

Component of the CPU which synchronises all activity in the computer. It regulates the speed at which instructions are completed

• Temporary area that a computer uses to store data in current use • Much quicker to access than the computer’s hard drive • Quickly recalls information

The size of the cache memory, compared to RAM

The speed of the cache memory, compared to RAM