Lecture 5 Computer Hardware and Architecture

• stability of basic computing model over time and the evolution of computer systems.

• the input-process-output model of computing.

• the basic components of a computer system.

• the major categories of computer and computer architecture.

Reading: Englander chaps. 1 and 6.

http://www.csm.uwe.ac.uk/~rstephen/courses/UQI108S1/

Architecture

• Rules concerning design, standards and protocols of: – Data

– Hardware

– Software

– Communications

• = architecture

Manchester University Mark 1, 1948

The fetch-execute cycle

PC architecture

Components

– Input devices - keyboard, webcam ...– Primary storage - RAM, ROM ...– Secondary storage - discs, CD, tape ...– CPU - ALU + control unit + registers– Output devices - Printers, monitors ...

4 milestones in business computer architecture history

– 1964 - IBM S/360 (mainframe)

» centralised business computing

– 1970 - DEC PDP-11 (minicomputer/midrange)

» decentralised and departmental systems

– 1974 - Cray 1 (supercomputer)

» scientific computing

– 1981 - IBM PC (microcomputer/PC)

» desktop computing

Mainframes

• Centralised

• Costly - £xxM

• Require custom built environment

• Specialised staff

• Support batch processing environment (schedulers)

• Support large databases

• Support 1000s of terminals

• e.g. IBM S/390

Minicomputers (or midrange)

• Decentralised or distributed (networked)

• Broad range of costs from £10K-£1M

• Departmental systems

• “Turnkey” systems

• Transaction processors (interrupt handlers)

• File servers for Local Area Networks

• eServers for Electronic Commerce

• e.g. IBM AS/400

Microcomputers (or PCs)

• Desktop computing

• Single user, single tasking

• Linked by Local Area Networks

• Inexpensive for the individual, £1,000.

• Expensive for the corporation! (Initial cost and support!)

• e.g. Compaq, Dell, Apple, IBM

Current Trends

• Mobility

• Ubiquity

• Embedding

Summary

Computer architectures = data+hw+sw+comms. The block diagram for the PC is a good basis for

understanding all standard computer architectures. Understand the evolution, rather than revolution, of

architectures from S/360 to Servers to PCs to …. Be able to describe the main categories of

architecture: Mainframe, midrange and PC.

Tutorial and Labs

• Review the operation of the Little Man in the Computer (Englander, chap. 6)

• Discuss the differences of the 3 main computer architectures:

a) Mainframeb) Midrangec) PC• Review the instruction or fetch-execute cyclehttp://www.csm.uwe.ac.uk/~rstephen/courses/UQI108S1/