Lecture Structure

1) Computer generations

2) Software approach

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3) Friedman’s computer systems

development model

4) Conclusion

First Generation Systems 1943 – 1955

* ENIAC (Electronic Numerical Integrator And Computer)

* 18,000 vacuum tubes or valves

* Designed by J.W.Mauchly ; J.P.Eckert, University of Pennsylvania for US military during WW2 to calculate firing tables

* Big ; hot

* UNIVAC – Remington Rand, first ‘commercial’ computer

1. Computer generations

First Generation Systems 1943 – 1955

* ENIAC (Electronic Numerical Integrator And Computer)

* 18,000 vacuum tubes or valves

* Designed by J.W.Mauchly ; J.P.Eckert, University of Pennsylvania for US military during WW2 to calculate firing tables

* Big ; hot

* UNIVAC – Remington Rand, first ‘commercial’ computer

Second Generation Systems 1956 – 1964

* Transistors (developed in AT;T’s Bell Lab) replaced vacuum tubes

* Brattain, Shockley & Bardeen

* Faster, cheaper, smaller, more reliable

* IBM 1401

Third Generation Systems 1964 -1980

* Integrated circuits.

* Jack Kilby 1958 Texas Instruments

* IBM System 360 (1964) and S/370 (1972) family of computers.

* Cemented IBM’s dominant market position

* Smaller still, more powerful

Fourth Generation and Beyond

* Microprocessor Intel 4004 1971

* Personal computers -Altair, Apple, Spectrum

* 1981 – IBM PC+its clones ; workstations

* Computer networks ; distributed computing

* hand-held ; mobile devices – phones, PDAs, small computers etc

History of computing is divided into different stages or succeeding generations of hardware. Each generation is characterised by a major change or improvement in the hardware…often summed up in tables like this one.

‘HARDWARE GENERATIONS’ ANALYSIS

OF THE DEVELOPMENT OF COMPUTING

GENERATION HARDWARE TIME

1st Valves 1940-50

2nd Transistors 1950-63

3rd Integrated Circuits 1963-79

4th Microprocessors 1979- ?

This approach has it uses..helps to fix some dates names and important developments in our minds

BUT

It is limited in its scope..simplistic ; not sufficiently linked to changes in society and so is a very STATIC view. It also does not recognise that software and user issues are now the main drivers of growth and change.

2.

Software approach

History of OS

First Generation Systems 1943 – 1955

* ENIAC ; UNIVAC

* No OS – basic functions programmed manually using switches

* Govt, military, very big corporations

Second Generation Systems 1956 – 1964

* Powered by transistors (Bell Lab)

* Large scale batch processing jobs controlled by highly skilled computer operators.

* Clear written instructions provided by programmers ; fed into machine by operator using tapes/cards.

* Slow and expensive process – machines standing idle during loading and printing.

* Development of OS began the automation of many of these tasks ; the deskilling of operators.

* Also beginning of the automation of programming tasks. e.g. instead of writing new printing instructions for each job, device drivers were developed.

* Other commonly used routines were given the same treatment and eventually organised into ‘libraries’ that could be inserted into programs as needed. Libraries are part of all OS now.

* User base spreading to big business

Third Generation Systems 1964 -1980

* Integrated circuits.

* IBM System 360 (1964) and S/370 (1972) family with own specially written OS.

* Cemented IBM’s dominant market position..you never get fired for buying IBM

Mainframe OS developed quickly in this era as computers shrank, became more powerful and spread into many areas of commerce.

Fourth Generation and Beyond

During this time software gained the upper hand, becoming the main driver of the computer industry, particularly the personal computer market.

* Personal computers -Altair, Apple, IBM PC+its clones & workstations

* Operating Systems – MS-DOS (1981) + UNIX (1983)and Windows (1985)+ Linux (1991)

* Killer apps…SS & Wordprocessing etc

* Computer networks – network operating systems, the internet

* Distributed computing – distributed operating systems – client server

* Web based OS

* OS for hand-held & mobile devices

A useful model as it fills in many gaps, has a lot more emphasis on the user and the work process of producing OS.

3.

Friedman’s Model

Friedman (1989: 3) argues for a ‘historical’ and ‘analytical’ approach to computer systems development.

(note that he calls it computer systems not just computers..a holistic and rounded approach)

Friedman, A. (1989) Computer Systems Development: History, Organisation and Implementation, Chichester: Wiley.

This analysis MUST be based on:-

‘models of social change’

;

‘management strategies for organising work’

(1989:3)

Like the other approaches F’s model is also structured in a ‘series of phases’. In each phase a so called ‘critical factor’ acts as a constraint on further development. (1989: 4)

How does change occur?

(a good question that is not sufficiently addressed in our other approaches)

F (1989: 4) says –

‘Efforts to overcome a critical factor(s) stimulates changes…’ in

i. management strategies

ii. importance of computer systems

development

iii. direction of technical change

5 reasons WHY critical factors are important

* Technological change in s’ware ; h’ware

* Change in types of systems developed

* Change in user base

* Change in market & competition

* Shortages – skilled & experienced developers

Why Historical/Analytical Approach?

* Hardware & software approaches are useful but not sufficient to explain WHY systems develop as they do

* Computer history (as all technology) is not simply linear..this is too simplistic.

* Change is complex

How do you know where you are if you don’t know where you’ve come from?

How do you know where you are going if you don’t know where you are?

HISTORY MATTERS

Thus using this model it is possible to examine more closely the relationship between technical change ; social change

Technical change is one in a RANGE of factors associated with social change.

What is Friedman’s model?

THREE PHASES in DEVELOPMENT OF COMPUTER SYSTEMS

distinguished by

key areas of problems/limitations or ‘bottlenecks’

Phase One

emergence of modern computer in late 40s to mid-60s. Focus on hardware development and constraints:- cost, size, performance

Phase Two

mid-60s – 1980s. Hardware no longer major problem, and its cost was falling, software development and constraints became the focus: cost, operating systems, programming skills shortages, development of high level languages, systems analysis & design, new applications s’ware etc.

FALL IN RELATIVE COST OF SOFTWARE

1955 20%

1965 50%

1970 70%

[Boehm 1973 in Friedman 1989: 73)

Phase Three

1980s to present – hardware and software challenges largely met.

Role of USER in the system now the main area of focus

?

PCs with user-friendly GUIs, high-level programming languages etc.

new devices – small computers, handhelds, phones, PDAs, …merging/fuzzy boundaries

Phase Four?

Unclear but my guess is……

?CONNECTIVITY?

4. Conclusion

‘Hardware generations’ approach in particular is limited in scope.

Friedman’s ‘phases’ approach brings out more issues:

* what was the main area of research and development at the time

* what computers were being used for at the time

* who a typical computer user was at the time

* what the computer market was at the time

Bibliography

Augarten, S (1984) Bit by Bit: An Illustrated History of Computers, London: George Allen & Unwin.

Bandyopadhyay, N (2000) Computing for Non-specialists, Harlow: Addison Wesley.

Freeman, C & Soete L (1997) The Economics of Industrial Innovation, London: Pinter.

Friedman, A. (1989) Computer Systems Development: History, Organisation and Implementation, Chichester: Wiley.

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