Category Archives: ZX81

3D Monster Maze for Sinclair ZX81

3D Monster Maze Cassette
3D Monster Maze Cassette
As an 11 year old with an interest in computers, what better birthday present could I get but the latest in home computing the Sinclair ZX81. During the 1980’s you could buy computers from John Menzies, which for the under 40’s was a store a bit like WH Smith but with more calculators.On unpacking my new best friend I plugged it into the mains and my old black and white TV, tuned to channel 36, and started typing in some BASIC commands on the plasticky membrane keyboard.  After about 10 lines of code I got an out of memory error. Apparently I had filled the 1K of memory. So Dad got me a 16K RAM pack, which was attached to the expansion board at the back and held on with velcro.  As long as you didn’t jog the keyboard too hard and dislodge the unit, this extra memory let you type in (and load) much larger programs.

3D Monster Maze Sinclair ZX81
3D Monster Maze Sinclair ZX81

My favourite of these 16K games was called 3D Monster Maze, from a company called New Generation Software, which saw you running away from a Tyrannosaurus in a randomly generated 3D maze. Given the limitation of the computer’s graphics, which were in-built character blocks in black, white and shades of grey only, the effect was amazing.

The game managed to really ratchet up the tension as you tried to escape from the Tyrannosaurus, with the status line on the screen telling you how close the Tyrannosaurus was. A bit like Doom did over 10 years later, the tension while you waited for the monster to appear made the game.

Remember this was a first person perspective 3D game, back when you had to load the game from tape, and the computer would randomly reset at regular intervals when it got too hot.  To say it was ahead of it’s time was an understatement.

A great classic from a time when lone programmers working in their bedrooms could release a number 1 selling video game, and proof that you don’t need high definition colour graphics and surround sound to create an atmospheric gaming experience.

Sinclair ZX81 old school computing

It’s 1981, and I’m an 10 year old boy fascinated with the emerging world of personal computers.  My dad would bring home a Commodore Pet machine from work, the same shape and size as a small car, over the Christmas period. I would spend hours playing Snake (yes, years before Nokia got in on the act) and various dungeon based games punctuated by, well punctuation, as the character “sprites” on screen were all “$”s and “&”s.

Sinclair ZX81
Sinclair ZX81
At the weekend I would lurk around the local Tandy store (UK equivalent of Radio Shack, now long gone) and marvel at machines like the TRS-80 and TI994A, looking through the software catalogues and imaging how good the colour screens on these machines would be, and how advanced the graphics looked.

From here I would head off to John Menzies (another long forgotten chain of stores) and see what computer magazines were out.  It was here I found the mythical Sinclair ZX81, on sales amongst the typewriters and led calculators.  This was a chance to own my first proper computer, and for less that £80.  My 11th birthday came, and so did the little black box with my new ZX81 inside.  After unpacking the hefty manual, and plugging in to my black and white TV (tuned to channel 35) I was good to go.  

So what next?  Well, you were presented with a little blinking cursor, and that’s it.  No hard drive, no windows, no mouse, no idea what day it is, who you are, or what it was doing yesterday.  Every day was day 1 for a ZX81, and you had to tell it what to do, from scratch, every time.

So I read the manual. And I started programming, got my name printed on the screen, tried some FOR..NEXT loops, played with input and output, and then when I got to line 15 of my programme – “OUT OF MEMORY”.  Yes I’d reached the 1k RAM threshold of the standard machine.  Yes 1K – that’s 1,000 bytes.  I’ve just saved this document in Word and so far it’s 12K.  My toaster has more memory.  Dad is promptly dispatched to Menzies for a 16K RAM pack and I can complete my program, albeit very gingerly, because whenever you bash the plastic membrane keyboard too hard the RAM pack wobbles and you lose all the code.

Master program completed (a question and answer session that tells a “knock-knock” joke), I want to save my magnum opus.  Enter the cassette recorder, a new C90 tape, press play and record and type “SAVE”.  A wobbly screen and a few seconds of squawking later, and the programme is saved for eternity – or until you tape over it with the Top 40 on Sunday.

Looking for some hardcore gaming action, I would peruse the back pages of the computer magazines, and send off a cheque or a postal order for the latest game – no online reviews, no screen shots, just the programmers often exaggerated description of the gaming delights on offer.  Eventually the tape would arrive and you would spend several hours trying to get the tone of the recorder right in order to load the game correctly.  It was pot luck if the game was any good or not, personal highlights for me were John Ritmans Namtir Raiders, and my all time favourite 3D Monster Maze.  What these guys could do with a black and white low-res screen was amazing.  Much of the rest were variations on letters chasing other letters around the screen in complete silence.  

Time passed by, and I moved on to the Spectrum, what with it’s “real” rubber keyboard and flashy full colour graphics, and the ZX81 became redundant.  I can’t however forget how it introduced me to the world of computing, and that I knew this was the start of something big.