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Computer Science (CS) versus Information Technology (IT)

What is the difference between CS and IT?

  • CS is mainly concerned with the invention and development of new software and hardware.

IT is mainly concerned with the selection and use of already-available software and hardware.

  • Both CS and IT entail research, requirements analysis, and design for purpose: but they ask different questions and use the results in different ways.

CS asks: what new system, as a collection of code and electronics, can be designed and should be built? Would it be useful, either immediately or in the future?

IT asks: what new system, selected from catalogues of available code and electronics, should be purchased and employed? And how should it be employed, and people trained to use it?

  • CS includes the study of how things work internally.

IT largely takes the internal workings for granted.

Both CS and IT look outwards in much the same way, studying how to provide systems for people to use efficiently or innovatively.

But, when they look inwards, they do so in very different ways.

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  • The building blocks of CS usually go down to a lower level than those of IT, although there are exceptions to everything.

CS does not normally ask, how does a transistor work? But it must ask, how does a computer work?

IT does not need to ask, how does a computer work? But it must ask, how does an office system work?

A computer scientist/engineer might ask: to make it possible for me (or others) to do this, what new system do I need to design and build?

An information technologist might ask: to make it possible for me (or others) to do this as soon as possible, and with the least disruption, what is there in the catalogues that I can choose to buy?

But both the computer scientist/engineer and the information technologist are likely to be concerned with cost and effectiveness.

  • The size of the system being built with those building blocks, the complexity of the system, and the strategic 'height' of the system, do not differ in principle between CS and IT.

Consider a mobile field-wide network for search and rescue in hard real time and in a hazardous environment, with safety-critical requirements. Is that CS or IT? Well, it all depends on your role in the requirements, specification, design, procurement, deployment and operation of the system.

Consider a static planet-wide network for airline seat reservation in soft real time and in a benign environment, with commercial-critical but not safety-critical requirements. Is that CS or IT? Well, it all depends on your role in the requirements, specification, design, procurement, deployment and operation of the system.

  • Once upon a time, someone invented the spreadsheet. They not only imagined it and identified a need for it, but they also designed the first example of it, and implemented it by writing a computer program in a programming language. That innovative step was CS.

Later, other people improved the design and improved the implementation and marketed competitors. They interacted with customers.

The activities of choosing and using a spreadsheet, and finding ways of using it more effectively, and educating other people about its choice and its use, are all IT.

This example is instructive because it shows that the extremes here are CS and IT; but, more importantly, that there is a large grey area at the cross-over, where the 'CS or IT' question has no clear answer and is largely pointless. Nevertheless, one must do one's best to answer it.

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  • CS includes applications in which the computer forms just part of what is being studied ('embedded systems'), especially systems that operate within real-time and safety constraints. Engineers who are designing the computer hardware and software that are going to control a jet engine in flight, in real time and safely, are doing CS.

Those same engineers, when they are using spreadsheets and graphics and other design tools in order to carry out the clerical and draughting activities that are part of their operations, are making use of IT. And so are the personnel staff who appointed the engineers, and the accountants who are costing the design and production of the engines, and and the marketing and sales staff who are going to sell the engines. They will be using software that has had its own requirements analysis and that has been selected against competing systems, and for whose use there will have been a training programme. All of that is IT.

  • How do you design the computer hardware and software that control a DVD player? That is new hardware and software; it is CS, not IT.

Similarly, new computer hardware and software in a medical MRI scanner. Or a new intelligent software system for medical diagnosis, or for the automatic prescription and design of pharmaceutical drugs. That is CS in collaboration with medicine.

But when well-established software of this kind is marketed, and appears in catalogues, and is evaluated and chosen and purchased and used by people who see themselves as medics rather than engineers, they regard it as IT, not CS. That is IT in collaboration with medicine.

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'Airliner Studies'

  • An airliner is a large passenger aircraft.

Suppose you looked in the UCAS Handbook, and found a programme called Airliner Studies. What would you think it was about?

  • Suppose you contacted an admissions tutor at one of the universities offering it, and asked 'Is it about designing airliners?'

And they said, 'Oh, no, no. It is about managing an airline, of course'.

  • Then suppose you contacted an admissions tutor at another of the universities offering it, and asked 'Is it about managing an airline?'

And they said, 'Oh, no, no. It is about designing airliners, of course'.

  • And then you asked each of them, 'Does it include safety, capacity, efficiency, fuel consumption and other running costs, maintenance, availability, noise output, ease of flying, passenger comfort, catering, communications, purchasing and marketing?'

And they both said, 'Oh, yes, of course we cover all that'.

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  • You might be confused.

On the other hand, you might conclude that is was they who were confused.

You might offer yourself as a programme-naming consultant, and (when suitably remunerated) recommend that the first university call its programme Airline Management and the second call its programme Aeronautical Engineering.

(Both programmes would, of course, include a module called Airline Economics.)

You would be helped by the fact that some universities already have programmes called Airline Management or Aeronautical Engineering

  • You will realise the relevance to Computer Science.

There are many programmes called Computer Science, and even more called Computing Science, Computer Studies, Computing Studies or Information Technology that take an approach similar to the imaginary department of Airline Management just referred to.

There are other programmes called Computer Science, Computer Systems, Computer Systems Engineering, and so on, that have an approach similar to Aeronautical Engineering in the sense of the previous discussion.

So, what would you recommend in your role as a programme-naming consultant?

  • One problem is that Computer Science is both very ambiguous and also the name for which most applicants apply.

They search for Computer Science. They look up Computer Science. They have heard of Computer Science. But they may get very different things - very different approaches - from different universities.

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  • Another problem is that Computer Engineering is often (wrongly) taken to mean 'hardware only'.

That is why we have a programme called Computer Systems and Software Engineering.

It means Computer Systems Engineering; but also, just in case you thought software was not included, Computer Software Engineering as well.

That is, in effect, Computer (Systems and Software) Engineering.

  • We put a lot of thought and effort into naming our programmes.

We know we might not have got them quite right.

Please let us know what you think.

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