What lies underneath

23rd November 2007 at 00:00
What better way to find out how something works than becoming one of the parts yourself. Emma Seith finds out. Illustration by Hashim Akib.Ann McVey is the processor; Ann Laird the scheduler; Ian Cairns task one; Ian Phillips task two, and I am task three.

We are learning how a computer organises its workload by becoming the component parts and the jobs it has to do. Or rather, I am learning how a computer works; the rest, being computing teachers, already know. They are here to learn about Computer Science Inside and the workshops they offer.

For more than a year, this project, based at the University of Glasgow and led by Quintin Cutts, has been designing workshops to capture pupils' interest in computing science by looking at the science inside their mobile phones, the internet, and MP3 players.

CSI got off the ground because of the worrying decline in the number of youngsters choosing to study computer science at university - numbers have halved in five years. Dr Cutts and his colleagues in other Scottish universities believe they are being turned off at school, where computing has become too focused on how to use computers, with less emphasis on how the technology actually works.

"No one seems to realise we are becoming a nation of tool users, not tool builders," said Dr Cutts, a lecturer in computing studies at Glasgow University. "Pupils are being taught ICT - how to use technology - but not about what goes on underneath, how to build rather than use these systems."

CSI workshops, therefore, aim to bring computer science alive and get youngsters interested. To get schools started, Computer Science Inside will deliver continuing professional development to teachers or work with a group of pupils. This is a continuing professional development session for teachers from East Renfrewshire.

"We are going to go through a couple of workshops with you," says Dr Cutts, "so you understand them and present them without much more preparation."

We take on the role of pupils. The first workshop, Doing a Million Things at Once, is about scheduling or how a computer allows you to play a CD while typing into MSN messenger and receiving email. By turning us into the tasks, the scheduler and the processor, Dr Cutts demonstrates the difference between first-come-first-served and round robin scheduling.

During first-come-first-served I, for instance, have to wait while processor Ann McVey deals with Ian Cairn's task - reading a passage aloud - before my task (a join the dots puzzle) can be tackled and completed. Next time round, however, each task is given 30 seconds with the processor, then moves on regardless of whether it is finished or not, demonstrating round robin scheduling, and the way in which a computer can seem as if it's multitasking but is in fact just jumping constantly from one job to another.

Having ourselves become the different systems, we know from personal experience the pros and cons of each.

"Different scheduling mechanisms are suitable for different application areas," sums up Dr Cutts. "If it's a PC, it's sensible to have the round robin style, because you want the computer to stay responsive. But if it's a machine dedicated to processing bank transactions, it just has to grind on through task after task, so first-come-first-served is fine."

Parts of computing studies can be dry, admits Mr Cairns, principal teacher of computing at Mearns Castle High. It's because so much of it - like how the processor works - is abstract. "I would use this workshop," he says.

The second workshop, Finding a Needle in a Haystack, deals with how search engines, such as Google, find the information you want. Google looks through billions of pages each time you type in a search, says Dr Cutts: "So how does it work?"

Again we take on the role of pupils. Dr Cutts steers us towards the method of searching by getting us to think about how we search other information sources, such as books, bringing us to indexing. We search through several short documents, getting used to identifying the keywords and ultimately develop our own indexing system.

Dr Cutts reminds us that a computer has no intelligence and can only follow rules. It is established that there are words Google ignores - a, is, also, an, found - and that Google combines related words in its index by getting rid of common endings: s, es, ing.

Another Computer Science Inside workshop - Getting onto the Right Page - takes pupils one stage further by looking at not just how a search engine finds relevant pages, but how it prioritises the results.

Ms McVey, a teacher at Eastwood High, says: "There are CPD courses you go on and, while you find them interesting, you never use them again. This course helped my knowledge, will make lessons interesting for pupils and has provided extra resources."


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