Allan's place

My Computers

Yes, I am of the ZX81 era. I didn't actually own one of them, but I did get a Spectrum as they came out. It was, looking back, a pitiful machine but they were at the forefront of home computing - loading programmes by cassette tape a leap forward from having to key in all your programmes each time!. Calculators had not long been within the average families reach and were banned form school exam rooms. The digital age had dawned!

I had studied computer science at school (O and A level) and had got a job where computers were a key element and I was soon to specialise in their maintenance. Below is some information on some of the computers, and their peripherals, I came across at home or work. They may not be in correct chronological order and some of the details may have become distorted over time, but enjoy anyway....

  • The ICL/Elliot 4130 - This was a 'real' computer. It was used to provide real time flight simulation of the Harrier GR3 and Nimrod MR aircraft. It's maintenance pocket book boasted that it was 'fully transistorised and portable' - true, but this was no compact machine! To give an idea of their size, you might possibly get either the processor or the memory cabinet in the back of a large estate car, but that would be it. And it would require two of these machines to provide enough power for realtime programming. The memory was a large 64k words! Peanuts by todays measure, but these were 'proper' 24 bit words and built of ferrite core. Programmed once, with paper tape, the machine could be powered down and up and would continue where it left off (who needs sleep and suspend?)

  • Whilst I mention flight simulation, another'computer' of those early days was fully non-transistorised! The gnat flight simulator was a fully synchro and servo solution! Those early design engineers sure did know their stuff and created magic out of nothing.

  • As mentioned above the ZX Spectrum was my first home computer. Loading programs by tape was a frustratingly slow process by todays standard. The Atari ST, however, was something else. Floppy disks and hard drives were available. This machine, running the 68000 chip rather than the intel 86 and 16 bit rather than 8, was great to programme and packed some power!

  • The DEC PDP 11/45 - Wow, this machine had integrated circuits! The processor, it's memory and interface had shrunk so that it took up about 1/6 th the space of the 4130! Faster too, but still loaded with paper tape like the 4130. The PDP 11/70 was it's bigger (but younger) brother. Sporting 8 inch floppy disks and even the occasional disk drive (RK05 and RS04). And later on came the VAX 11 series, things were changing. In those days programming 'aide memoires' were common, here is the pdp11 Programming Card.

  • A little more about the Digital RS04 disk drive - This unit was used for it's speed in a radar simulation. It unusualy boasted fixed heads! So instead of disk heads seeking a track physically, this unit did it electronically and consequently saved precious time. very clever eh?

  • Of course things got smaller and more powerful, single board intel computers in the 1980's probably out performed my favourite 4130, but these machines had almost become throw away. Whereas I spent many hours with soldering iron, multimeter, oscilloscope and wire wrapping tool fixing the Elliot, these machines were 'swapped out' to be fixed in the workshop with the help of automated test equipment or sent back the manufacturer!

  • Concurrent Computer Corporation (an American company, I believe) built some fine computers in Ireland and I came across them in my flight simulation career. The 3280 was a fine processor and I was one of the team training newcomers to the Tornado Simulator on it's maintenance.

  • The 'Personal Computer' - yes the humble Intel 86, then 286, then 386, 486 etc machine became king. Compact, efficient and eventually affordable this series of machines are really the ancestors of the home and office machines of today.

  • In 2012 it was the Raspberry Pi - a bit like the early days, when the Spektrum and ZX80/1 were released. Fun to explore a new product and this one able to run Linux.

I currently own a laptop and couple of desktop PC's. My older PCs (I cant bear to part with all my old hardware!) provide server functions (ubuntu) and a firewall machine on the very good software: ipcop.

Please visit my other computer pages via the menu.