Computer History and Basics

Key terms relating to basics of computer systems and their history

Computer Architecture

The attributes of a system visible to a programmer and that have direct impact on logical execution of a program. E.g. available operations

Computer Organisation

The operational units and their interconnections that realize the architectural specifications. E.g. instruction set, number of bits for data types, I/O mechanisms

Instruction Set Architecture

Defines instruction formats, instruction opcodes, registers, memory allocation for data and instructons

CPU contents

ALU

Control unit

Registers

CPU interconnection - enables communication between other parts of CPU

What processors handle

Grahics, I/O, networks, calculations

First programmable computer

Konrad Zuse's Z-series 1938

Used punch film tape for input

5Hz clock

First electronic computer

Colossus 1943

Used 1500 valves, paper tape, 500 char/second

Not general purpose

First electronic general purpose computer

ENIAC 1947

Programmed with wires

Unreliable

Computer architecture vs organisation in practice

Many manufactures offer computer models with the same architecture but different organisations

One architecture can span many years with an organisation that develops over time - enables greater software continuity

Computer Functions

Data processing

Data storage

Data movement

Data control

Compute Structure Main Components

Central Processing Unit

Main Memory

Input/Output Devices

System interconnection

Single-processor Computer top-level structure

Multicore Computer structure

Printed circuit board (PCB)

Holds and interconnects chips and other components

Made of layers (usually 2-10) that interconnect via copper pathways

Core - definition and elements

An individual processing unit on a processor chip

Functional elements:

• Instruction logic - fetch, decode, execute

• ALU - performs operations

• Load/store logic - manages transfer of data

Computer technology progression

Vacuum tubes 1940s-50s

• Used vacuum tubes for digital logic elements

Transistors 1950s-60s

• Smaller and cheaper than vacuum tubes

• Solid-state device made of silicon

Integrated circuits late 1960s onwards

• Many logic gates and memory cells arranged in a grid

• I/O points