Acorn Electron

The Electron, the first computer I ever owned.

Published , updated by Richard GoodwinFiled under Computers

Less powerful than the BBC Micro A and B series, the Elk was a cut down, consumer friendly machine for people like me who couldn't afford the mighty Beeb.

My actual first Electron went back after just a couple of weeks with a broken keyboard; this is the replacement one which one served me for ages until I again broke the keyboard, this time by hard-wiring part of an old calculator keypad into it as an Elite weapons console (sadly not covered by the warranty). A full replacement keyboard would have cost as much as a replacement machine, so I saved up and bought a Slogger 64K Turbo Electron instead - an Acorn Electron with extra hardware that at the flick of a toggle switch (and a hard reset) could go into turbo or "turbo with extended memory" mode. A little later I got a reconditioned keyboard for fifteen quid which meant both machines were back to full working order.

The stock Electron didn't have much in the way of upgradeability - there was a single upgrade connector at the back, but no floppy drive interface or place for adding ROMs.  Eventually had several add-on floppy disc interfaces made for it, but for me it wasn't worth the expense of paying more for the add-ons than the computer itself cost. The number of times I played Elite and had to start from scratch, having written over the data file on some random C90 tape, doesn't bear thinking about though.

This is my other Electron, the upgraded one. The first box bolted onto the back is a Slogger ROM Box, which allowed the Elk to use BBC-style ROM chips to add word processing capabilities (such as AcornSoft's View, one of the chips in the picture), new commands (such as printing control, file systems etc.) or new programming languages (such as Forth, which I think is the leftmost ROM as you look at the image).

Behind this is an official Acorn Plus 1 expansion, which added the missing printer and analogue (joystick) ports, plus two cartridge slots. These slots could take carts which could do pretty much the same as the ROM chips on the ROM box, plus could take other hardware interfaces (such as a third-party floppy disc interface), and also game carts - mine came with Starship Command.

In this picture you can see a large cartridge with a red stripe, which is an Electron second processor - I didn't even know these existed, I picked this one up many years later - and a toggle switch on the right hand side of the picture shows this is a Slogger hacked version with Turbo and 64KB/Turbo modes.

Memory's too tight to mention

Memory was always tight on the Electron - it had 32KB of memory, up to 20KB of which could be eaten by the screen memory requirements (it didn't have a MODE7 teletext mode like the BBC, which only took 1KB of memory). Add the Plus One upgrade, and then a Plus 3 if you could afford it which stole more memory, and there was very little left. I think I could get about 1,000 words into the word processor before I had to spend about 10 minutes doing the save/load shuffle — saving the document to tape, then loading it back into an illegal memory area to verify it saved properly without damaging the version in memory in case I had to save to another tape.

The Slogger version (pictured above) gave 32KB of real memory, as screen memory was taken out of the 32KB of sideways RAM this hack introduced, with anything left over potentially being used as a print buffer — but Elite wasn't compatible with this hack, so I left the machine in standard 32KB mode for a lot of the time.

What the hell did you use it for?

I had great fun learning to program using the built-in BASIC.  I wrote a multi-mode graphics package, and an editor for the 8x8 system font system — both of which came in handy when editing the school magazine, which often featured what could charitably be called computer graphics on the front cover.

The Archimedes came out while I was at college, and I programmed them by writing the program on my Electron at night, saving to tape, using a Sony Walkman to transfer the data to a BBC, re-saving on a 5.25" floppy disc, and then using a serial transfer lead to transfer it to an Archimedes A310 with its 3.5" floppies. A couple of small files could take all morning to set up and transfer.

Another fun thing to do was find a radio/cassette machine with the motor control input used by the Electron to stop and start the tape; write a small timer program (as the Electron has no real time clock); and then when a favourite late-night radio comedy show started, the Elk would start the tape and it was like a video recorder for radio. I'd have to use a tin foil shield between computer and radio as the Elk put out some serious radio waves, you could tell what program it was running by listening to the interference on an FM radio.

Fox tale

I also heard that a fox had started using our garden as a short cut home. I'd never seen a fox back then — this was when the possibility of foxes living in cities was a new and unusual concept. So I wired up a light sensor I "acquired" from the CDT department at school to the analogue joystick port with several metres of wire, which stretched all the way from my bedroom window, down the back of the house and across the lawn.  I then put my Dad's bicycle light across from it as I'd heard foxes couldn't see red light. I assumed he'd be OK with this and forgot to ask him.

The software I wrote automatically adjusted for slight changes in light level over the course of the night, thresholding to account for slight deviations, and had a timed cut-off because I assumed it would become useless in pre-dawn light. Once triggered, a two-tone alarm triggered would keep going until I pressed the "reset switch" (space bar). In my memory the screen had a graph showing the light level over time and threshold lines for "blocked" and "too light".  However, I may be taking how I envisioned the code in my head and making it a real thing, because it seems unlikely I'd have had time to write a graphical display.

With so much prep work for one night of use you're probably expecting me to say that it didn't work, but about 3a.m. the alarm triggered, I flew to the window and there was a fox: it stood right in the middle of the lawn for several seconds looking around behind it, illuminated by the red lamp, probably wondering what the hell all this wire was, before trotting off to a hole in the fence.  That's the first fox I'd ever seen in real life, and all down to this crude tangle of wires and circuits.

What else?

Oh, and I played Elite on these machines. A lot.

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