It is not PC for the PC to Check Your PC

We were at my parents for the weekend and we all got presents. The youngest got a self-propelled Thomas the Tank Engine which fires out plastic smoke balls from its chimney. The boy is very wary of this and walks around behind it in a suspicious crouch with an occasional smile. My daughter was given a Lego Viking boat complete with rapid-fire catapult and snaky sea-monster. This is because my dad is aware that all children in the country will be “doing” the Vikings at some point. I had to put it together last night and tipped all the bits out onto a tray. It was most daunting. Even the horns on the helmets were separate and had to be pushed into place. It took an hour and a half to finish by which time daughter had gone to bed so the complete diorama was set-up on her table. She just woke up in time to see me off this morning and was most happy. What goes around … I remember coming down early one morning to find a huge Lego suspension bridge which my dad had made the night before. It was complete with string for cables and a slender deck which without proper suspension would not have stood up. In the chaos of a visit to the grandparents I don’t often notice much but I did see him explaining pre-stressed concrete bridges to his granddaughter with the aid of … yes … more Lego. He also showed her the model of a Shaduf he had made out of twigs for her cousin AND a windmill that really worked. This reminds me of the Kon Tiki story which I must have mentioned here before. Dad made me a model of the Kon Tiki using twigs and branches we got from the Malvern Hills. It was for a competition at school but I was adamant that it should not be entered because he had made it, not me. Years later I made a model using Balsa and sandpaper of which I was very proud but it got lost in the move – I say lost but I mean in the sense of wrecked as the bits arrived at the new house. I should try again sometime.

Anyway, my present was not wrapped, just handed over in a plastic bag. My old ZX81 complete with 16K RAM pack. There are two games with it – A flight Simulator and some space shoot-em-up; I don’t think I’ve got any tape machine which I could use to load them but it will be interesting to try it for five minutes. I have no manual but it is online here so a test might be carried out tonight if I can wrestle control of the TV away from the boy who wants to watch Wallace and Gromit over and over. I was thinking about how we used to try and squeeze as much into the 1K as we could. Even with a 16K expansion pack, it would not be difficult for one person to understand what every bit and peek and poke actually did to the registers in the CPU. I even wrote a few bits of simple machine code – I had Rodney Zak’s book on Z80 programming though I went onto 6502 later. This helped with my one commercial machine-code program. Well actually it was assembler but who makes that distinction these days? I didn’t get that excited about machine-code; it seemed unnecessarily complicated when you had high-level languages which probably was fore-shadowing. Now I have unlimited space for programs, the thought of going in and doing things at the lowest possible level seems quite exciting. At college, one of the dead-end course involved real-machine code programming to the extent that we had to program using bits of wire and connections to the pin-outs of the chips. It felt like torture at the time but what I wouldn’t give to have one of those boxes now. Still, you can simulate everything on a PC these days so that might be an option … after the Change ringing simulator and Six Pianos and the Fractals and everything else. Time to go and crash this PC