Tech/Worlde Presents

Fred Nachbaur's ZX81Page

It's been a long, long, time...

The Treasure Chest

Exclusive to Tech/Worlde - here is a selection of long lost work from ZX81 old-timer, Fred Nachbaur! Fred wrote some of finest software for the ZX81 and now after many years, his programs are again available to you. Without further ado - over to Fred...

Greetings, All!

Rev 1

After the decline of the ZX81 (I almost said "demise" -- but this page is proof that the ZX81 is alive and well!) I took an extended hiatus from computers in general, focussing my efforts on other areas... like music. So now I've got a lot of catching up to do, and started re-educating myself about two years ago by starting with a '286. I'm up to 486DX2 now, and am hoping to get a Pentium before it's obsolete... ;-)

Our gracious host Steven McDonald has generously offered space on his site for some of the ZX81 programs that my colleagues and I developed in the mid - '80's. Lest anyone think that the software provided here is all my doing, I hasten to add that it wouldn't have been possible without the hard work of people like Gregory C. Harder, Peter McMullin, Harvey Taylor, John Oliger, and of course Wilf Rigter. Most of the work here uses Wilf's "WRX16" true hi-res system, which in my opinion did more to elevate the ZX81 far above its original mission in life, than any other single product or development.

All the programs presented here will, of course, run on a ZX81/TS1000 with at least 16K of dynamic RAM (or TS1500), plus the all-important 8K static RAM accessible during refresh time. Some programs have higher system requirements, as indicated. The programs have also been tested on "ZX Emulator," a remarkable freeware ZX81 emulator. All run properly, with the following qualifications:

I sincerely hope that ZX Emulator will continue to be developed, I really like its compactness and modest system requirements.

Most will not run using V1 of "Xtricator." However, I've been told that they do run on the beta version of V2, again with a few qualifications. Carlo is working on this, and welcomes any assistance in beta-testing and further development.

Here are the keys to the system requirements codes:


Following is a listing of programs on this site. All programs are compressed into .zip files, even those that consist of only a single *.p file. This is to prevent difficulties with the Netscape browsers, which assume unknown file-types to be text mime-types instead of binary.

Click on the imbedded links (shown in orange) to download, or page down to the bottom of the page where all available titles are summarised in tabular form.

Fred Nachbaur

Program Descriptions

Download Table

Program Type Load Name Year Memory Hi-Res Docs Other Info
3-D Fractals Fractals 3DFRAC.P 1986? 16 WRX Reference given by G. C. Harder
Graphics Archiver Graphics ARCHIVE.P 1986 16 WRX Self- documenting Store/ retrieve WRX16 images
Bi-Plot Graphics BIPLOT.P 1987 16 WRX Self- documenting Real ZX81 only
Blackjack Card game BLACKJAC.P 1986 16 WRX N/A N/A
Block Buster Puzzle game BLOCK1.P 1986 16 WRX Self- documenting Good on ZX emulator
Calendar Application CALENDAR.P 1987 16 WRX To Follow 1987 sample
CE Amplifier Electronics CE.P 1983 16 STD maybe one day... Transistor amplifier design
of Ymir
Advent. game YMIR.P 1985 16 WRX To Follow
Design your own Dungeons
Fourier Analysis Maths App. FOURIER.P 1982, 87 32 WRX To follow
if found
sample data included
Hi-res Font Kit Fonts various 1986-7 16 WRX Self- documenting incl. Prop. font demo
F-Scapes Math diversion FSCAPES.P 1988 48 WRX Text Format
Write Format
Illustrations incl. in ZIP file
Hi-res Chess Psion chess HRCHESS.P 1985? 16 WRX N/A legal only if you own original
Invaders Arcade game HRINVADR.P 1987 16 WRX N/A Merry Christmas!
Julia Sets Fractal JUL-FFP.P 1987 16 WRX Self- documenting N/A
L-Systems Fractal L-SYSTMS.P 1987 16 WRX Reference given by G. C. Harder
Macro-Life Simulation MACRO-16.P
1986 16
WRX Self- documenting by G. C. Harder
Mandelbrot set Fractal MAND-FFP.P
1987 16
WRX Self- documenting includes quadric version
NIM-2K Strategy game NIM-2K.P 1984? 2 STD Self- documenting POKE 16389,72 on 16K machines
SRAM HR Ext. BASIC Program Language various 1987 16 WRX To Follow with G. C. Harder
Snorth Games Games Pak SNORTH.P 1983 16 STD May follow later incl. NFLX Football, Miner's Revenge, Super Slide, Storm Lander 3
Spirograph Simulator SPIRO.P 1987 16 WRX Self- documenting by G. C. Harder
VDAQ1-HR Data acquisition VDAQ1-HR.P 1985 16 QHR lost N/A
Voyage of Peril Advent. game VOYAGE.P 1987? 32 WRX N/A
by G.C. Harder
Wa-Tor Simulator WATOR.P 1985 16 QHR Can't find it N/A
ZX-Paint Graphics ZX-PAINT.P 1987 16 WRX N/A Oh, wow!
by G. C. Harder
ZX*TERM*80 Xmodem Terminal ZXT80-25.P 1987 16 up,
WRX May follow later
if worth retyping
see description

All content 1999 Fred Nachbaur.

This page was last updated on February 14th, 1999.

If you have any questions or comments on this site to pass onto Fred, you can contact him below.

Fred also runs his own excellent website which is well worth a visit at: or

Thank You.


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