8 Bit Mid-life Crisis

Ok, so I realised last week that I am going to turn 44 this year. Shit the bed, how did that happen? Then I started reminiscing about my youth (yoof!) and of course like most spotty oiks when I were a lad, I was completely consumed by the home computer revolution of the 1980’s. All my mates were computer nerds, as I’m afraid was “yours truly”.

One Christmas, my parents gave me a ZX81, and I found myself immersed in the world of Sinclair BASIC and LET EGGS = 58 (yes I still remember that from the manual!).

After struggling for an age to get my tape deck to load stuff (I didn’t have the volume loud enough) I was soon playing JK Greye Breakout in just 1K of RAM – absolutely incredible. Then after scrimping enough money from my paper round to buy a 16K Memotech RAM pack (didn’t suffer from RAM pack wobble like the Sinclair unit) I was then able to run 3D Monster Maze and Mazogs!

But after a while I got my grubby hands on a ZX Spectrum and wow, I turned into an uber-nerd, not only typing stuff in from magazines, but writing my own code and submitting it to the magazines of the time for publication. I taught myself Z80 assembly language programming and got to the point where I could use the interrupt handler to output smooth scrolling graphics with no flicker.

Of course, during this time the UK was going nuts for home computers and all my mates at school had either a Spectrum or Commodore 64, which meant there were tons and tons of games to copy and swap. I had two tape decks so tape-to-tape was no problem, but over time the “copy of a copy of a copy of a copy” would produce a dodgy tape or you would get a tape that needed so much azimuth alignment you just couldn’t get it to load. I had a tiny screwdriver on permanent standby to tweak the azimuth of my tape deck as when you borrowed copied tapes, invariably you would find they were out of alignment, but it was dead easy to adjust, you just twiddled the screwdriver until you heard the noise get REALLY screechy. Ah they were the days…. durrrrrrrrrr dit……. durrrrrrrrrr dit-dit-diddly-dit… So anyway, even though I was turning into a bit of a nerd, I had loads of mates at school to swap games with, although probably no-one really to discuss the finer points of Z80 assembly language programming (DJNZ anyone?).

I expanded my Speccy with an Opus Discovery disk drive, used the composite video output with a proper green screen monitor, plugged the centronics interface into a Tandy dot matrix printer, added a second 3.5” floppy drive, upgraded the Opus PSU with beefier transistors (I was into electronics at the time too), used a Multiface 1 to dump games to disk and built various electronics gadgets to plug into the edge connector at the back. I had a technology project in my last year at secondary school that used the Speccy to interface to a piece of Scalextric track with micro-switches embedded into it to detect false starts and also time the laps, but I remember having some problems and the teacher couldn’t help me at all saying “You’re way ahead of anything I could do Paul, sorry you’re on your own!”

Another project was a speech synthesizer based on the SPO256 speech processor. You could buy devices like this that plugged into the back of the Speccy which allowed it to talk, but I designed and made one, including the PCB, which I etched with Ferric Chloride in the kitchen (giving my Mum and Dad kittens as this stuff eats stainless steel sinks!). So then I had all sorts of fun teaching my Speccy to say rude words! When I left home I dumped a load of my electronics stuff on a mate and he still has this in his shed. I was amazed he hadn’t thrown it all away!

Something else I had “fun” with was an SRAM paging device that I designed and built. This let me page in chunks of SRAM into the Speccy’s memory address space – I remember one problem where the Speccy had a bug in it’s ROM so that if you generated a non-maskable interrupt (i.e. via a push button) the Speccy would do a reset instead of jumping to your code. So with my gadget I could copy the ROM into SRAM, fix the offending bug, then page and map the SRAM over the ROM so that when an NMI was generated you could call your own bit of code (which could page in more SRAM from my gadget) instead of causing a system reset.

Somewhere along the line the original rubber keyboard packed up so I added a Saga keyboard and I remember ending up with a staggering array of games on tape and disk, and all sorts of associated detritus.

Now I think back and realise I have forgotten everything I had learnt, and probably more! I used to type machine code in raw hex for Christ’s sake, I used to know most of the hex codes and their corresponding Z80 opcodes, I could calculate relative jumps and offsets in my head, it really was like programming “The Matrix” – until I got my Z80 assembler which made life so much easier and I absolutely loved it. I used to spend so many hours in my room glued to the monitor that my parents got genuinely worried about me.

Like I said, I went a bit overboard and don’t remember being very sociable, until I left school and discovered alcohol and girls. I think the Speccy soon got abandoned after that! Also I moved on, acquiring a Sinclair PC200 from somewhere and joining the grown-ups at work with their PC’s (we were amazed when we got an IBM 16MHz 386 at work, it was sooooo fast!) Eventually the whole lot ended up getting put into a big box and got posted off to someone who saw my ad in the Yellow Free-Ads.

Damn I wish I had kept all that junk, because now I have just bought a 48K Spectrum off ebay for 20 quid. And then I stumbled across this like-minded soul here…

Oh dear, what HAVE I started!