INTRODUCTION

Hello, Let me introduce myself – I’m wilf_zx. After a few years of pursuing other interests (BEAM robotics), I have returned fresh with new ideas and ready to once more design some new ZX81 hardware and software.

It is always a delight to contribute a project to the worldwide ZX81/TS1000 community, which for many has been an opportunity to relive our first contact with computers.

The ZX81 was a complete turnkey computer system requiring only a connection to a TV to provide instant gratification of our hunger to become computer literate. .

Hardly bigger than a calculator, the ZX81 was a study in technological economy. The flipside of it’s elegant simplicity was a severely limited “out of the box” capability. For example, with 1K or 2K bytes of RAM, using the membrane keyboard, to type in small Basic programs was manageable but with the expanded capability of 16K RAM pack, typing in programs lines, text or data for word processing or spreadsheet programs was well nigh impossible.

The speed of the ZX81 made Basic programs too slow for most games, spurring interest in designing machine code programs.

The screen resolution of the ZX81 graphics was another apparent limitation for game designs requiring creative use of standard screen character often resulting in a unique appearance of ZX81 game screens compared to those of other machines and for that matter to the fine graphic accompaniment in the advertisements for those ZX games. The screen resolution limitation was eventually overcome when hidden hires graphics modes were discovered in the ZX81.

All those ZX81 shortcomings and a lack of technical support from Sinclair created a technological vacuum, which third party programmers and hardware designers of the early 80’s were only too happy to fill.

Within a short time of buying my ZX81 kit in late 1982, I joined a user group (Vancouver Sinclair Users Group - VSUG) and spent many happy hours swapping programs and ideas with kindred souls. I also tried my hand at ZX81 hardware and software projects and over the years became quite good at finding simple solutions to make up for the limitations of the original ZX81 design.

Within a few years (late 1983), the ZX81/TS1000 was orphaned by the availability of more capable machines at similar prices. Support dwindled, glossy publications ceased and many users moved on to bigger and better PCs. But some users, user groups and designers continued to be involved with the ZX81 well into the 90’s, still fascinated by the simplicity of this last completely knowable personal computer which was in many ways remarkable intuitive and well adapted to humans.

Nine years ago, after much water under the bridge, I discovered that Sinclair users were still alive, gathering in groups on the Internet and I found there a treasure of ZX81 emulators and every possible program I always wanted to try out, ready to download and play, requiring every ounce computing power of my 286 computer to run in ZX real time.

Revisiting the ZX81 today is a little like technical time travel. Not quite as ancient as toggling front panel switches of the earliest mini-computers, still hacking the ZX81 four chip motherboard and writing programs of a few kilobytes provides a stark contrast with the unfathomable depths of modern machines with gigabytes of storage and megabyte programs running on hardware equivalent to millions of logic gates.

I recently became aware of a new website in the US appropriately called www.ts1000.us , dedicated to the TS1000 and ZX81. I recommend the well organized message boards at that site as a good forum for discussion of all things ZX81.