The Spectrum Show

Dedicated to the Sinclair ZX Spectrum

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The Sinclair ZX81

It’s the bank holiday and what better way to spend it than messing about with old computers? Well, ok, there probably are better things to do, but having to stay in to do some work, my old ZX81, sat on the shelf next to me caught my eye. Would it still work?

I dug out the PSU, an old tape recorder and a few games and set it all up. The TV/Monitor I use for The Spectrum Show wasn't happy about it, and refused to tune in to the weak ZX81 signal. Not deterred I retrieved my old TV from the attic, knowing this little baby displayed everything I threw at it. Sure enough, a few minutes later and I was looking at a usable picture. The 16K ram pack even worked, and after a few minutes Galactic Trooper was loaded and ready to play.

This is where I started with computers, playing silent, black and white games on a small television, struggling with the touch keyboard and hoping I didn't cause the ram pack to wobble. The Sinclair ZX81 was the micro that brought computing into the homes of normal people. Before it, the ZX80 was only really taken up by enthusiasts and electronics buffs, but the 81 broke the barrier.

For the electronics buffs, they could still buy it in kit form and build it themselves, but for your average kid, they could get it ready built. There was no need for a monitor because it ran off the television, and loading data was done from the standard tape cassette player we all used to records songs from Top Of The Pops.

The software market too was part of the draw. The ZX80 had little in the line of games, it’s poor screen routines made that almost impossible, but the ZX81 fixed all of those problems and game companies soon began to sprout up.

The Hardware

The machine itself was tiny and very light. You wondered how such a small plastic box could allow you to play games on your television. It measured approximately 16.5 x 17 cm and 4cm high at the back, sloping to just 1.5cm at the front. The keyboard was flat with no moving parts, and the pressure from your fingers caused a membrane beneath to make the lightest contact. This had advantages – it was waterproof and had no moving parts to break, however it was terrible to use. The now familiar keys had multi functions with keywords, symbols and maths calls accessible by using the SHIFT key, the FUNCTION key (which doubled as a NEW LINE key) or switching it into graphics mode by using a combination of SHIFT and nine.

Connections were limited to just a power socket, Mic and Ear sockets for your cassette player and a TV socket, all on the left hand side. At the rear was the expansion bus that allowed peripherals such as printers or joystick ports to be attached.

The basic machine came with 1kb of RAM and 1kb of ROM. The ROM contained the BASIC language along with all of the routines to load and save, handle the keyboard and expansion bus. There was not much you could do with 1kb and so memory expansions were soon available, taking the machine up to an eye watering 16kb. Once you had this expansion, the amount of games rocketed. The downside was that if not connected properly, or moved in the wrong way, it would crash the machine. This phenomenon was labelled Ram Pack Wobble.

Output was in black and only, and in low resolution (64 x 48 pixels) with no graphics to speak of. When used in graphic mode some of the keys produced block patterns, breaking the normal character square into 4 x 4 blocks. These were all the machine had, and all that game makers had to work with. There was no sound. Nothing. Zilch.

Software

Software wise, there was a large mixture of programs available including word processors, databases and of course games. There are a few of these games that have gone down is history and are always mentioned when talking about the ZX81.

Monster Maze if probably the most famous. Trapped inside a 3D maze with a T-Rex chasing you was one of those experiences that had a lasting impact on many people. Mazogs is probably the other game that gets remembered. This two dimensional maze treasure seeking game has great animated graphics and a mixture of gameplay. There are of course many others, 3D defender, Black Crystal, QS Scramble and Galactic Trooper are all worth a play.

For all of its problems and the corner-cutting build quality, these machine were pretty robust. There are hundreds, if not thousands of these machines still working and still giving enjoyment to fans around the world. This machine was the catalyst of the UK games industry, and it certainly deserves its place in history.