This was the computer that changed my life. I had been wanting a computer for a while and I knew my parents couldn't afford some of the other machines on the market at the time. Apple II, Atari 400 and 800, or even the commodore VIC 20. In New Zealand in the early 80's, with it’s archaic import tax laws, these machines were thousands of dollars. The cheapest thing going at that time was the Sinclair ZX80, but even that was beyond anything we could afford. I also secretly suspected that my father, being of a different generation, considered such things a passing fad, or worse, toys.



Sinclair

ZX81

It wasn't until the even cheaper Sinclair ZX81 was released that I could once again approach my Dad and ask him to get me one. I had been saving up money from mowing lawns around the neighborhood, but I was still woefully short. At that time I also got very sick with acute appendicitis, and I was hospitalized for a few weeks. When I finally got home, I was greeted by a box containing my new pride and joy. The ZX81 was bare bones as computers get. Measuring a poultry 167mm x 175mm x 40mm. Having never actually seen one in the flesh, it's dimensions were shockingly smaller than I had imagined. I could see how my Dad though of it as an expensive gimmick, but to me it was a world of possibilities. Thanks Dad. I didn't have any commercial software to play, so I taught myself ZX Basic from typing in programs from magazines and dissecting them to see how they worked. Typing on the tiny membrane keyboard was certainly a chore, but after some practice I became quite proficient at using the different functions that provided faster entry of programs. Even today when I break out my ZX81, many of the old finger contortions are still familiar to me. At the time I only had the basic 1k machine, so any program I typed in wasn't so long anyway. It wasn't until much later that I could afford a 16K RAM pack, and was able to code much larger programs. Although the dreaded RAM pack wobble was frequently a cause of anxiety, often causing me to lose programs after spending hours tying them in. However this never dampened my spirits. When you are young and there is a tenacious will, there is certainly always a way.


A few years later I upgraded to a Sinclair ZX Spectrum, although I loved this machine very much, with its sound, color and high resolution graphics, it never touched me in quite the same way that my original ZX81 did.


Much later in life, when I first started collecting these old computers, the ZX81 was one of the first on my want list. One day I sat down at the machine and decided I would write a new ZX81 game, it was destined to become the grandest piece of code I had ever written, although that isn’t really saying much. It started out as a simple process, but like all things the game grew and grew, of course I soon moved the program to an emulators which would allow me to program easily and save without the fear of the programs never loading back again. This made the process much easier. After about 2 months I was basically done. As I don't know how to program in machine code, the entire program was written in Basic and took up a full 16K. I was then able to compile it into machine code using a program called Mcoder II. This allowed the game to run significantly faster and smoother. The game is called 'Chopper Drop 3000'.


A very important part of my hobby is having a good library of easily accessible software for all my machines, and the ZX81 is no exception. I purchased a ZXpand drive which stores programs on SD card. This modern drive is extremely convenient and easy to use and has the possibility to be expanded further with an AY sound capabilities and joystick add-ons. I highly recommend it for anyone looking for a simple storage solution for the thousands of programs available from online libraries.


RAM 1kB expandable to 16kB

ROM Sinclair BASIC


Keyboard 40 key membrane


Released 1981


Price Assembled UK£69.95 / Kit UK£49.95 / PSU UK£8.95

 
SPECIFICATIONS

CPU Z80


Speed 3.25MHz


Video Mono composite


Graphics 24x32 characters - 64x48 or 256x192


Sound None