In my day...

I heard this little story on the radio on the way to work this morning, it's about an A-level ICT teacher who is encouraging his pupils (with much moaning) to learn how to program using an antiquated  BBC Micro. I applaud him, computers these days are black boxes, in my experience, even professional programmers seldom really understand how they work. Like car engines and washing machines the every-day tools we use are mostly beyond comprehension to most people, this is a bad thing, it means simple faults and problem diagnosis are out of reach, the limits of the machines are not understood and expectations are either too high or too low and most importantly of all black boxes stifle innovation.

Fundamentally computers haven't changed in 40 years, you have a processor, on-line storage, off-line storage and a way of putting stuff in and getting it back out again (i.e. a keyboard and a screen). Sure there is a lot more to think about now, particularly since the internet came along this has meant that the number of ways of getting stuff in and out has increased hugely and the volume and location of data has changed beyond recognition but the basic block diagram of the main components and their roles are still essentially the same.

When I started programming machines like the BBC micro had memory capacities of 32K (or 32,768 bytes) or much less, my first ever computer (see picture above) had 16,384 bytes of memory or 16K, no disk and a single processor that could handle about 3 million instructions per second. Simplistically you had to fit all your programs and data into that small space and that forced us to be ultra-frugal with resources, efficient, in other words. These days, a simple document containing the sentence "the cat sat on the mat" takes up 11,000 bytes and this balloons to over 14,000,000 bytes when you include the Microsoft Word program that you need to edit it.

Luckily memory is dirt cheap now and most PC's have at least 1 or 2Gb as standard, that's 1,000,000,000 bytes. To illustrate our progress, the machine I'm editing this on has 8Gb of memory another 2,000Gb of disk space and a processor with 4 cores, meaning it really has 4 processors running at roughly 3,000 million instructions per second each. Then it's connected to the internet via a high speed fibre optic cable that can shunt data around at the rate of 10,000,000 bytes per second and people estimate that the internet contains roughly 500 billion gigabytes (that's 5 with 15 zeros after it) of data, the bottom line is, these kids don't know they're born! :)