The Sinclair ZX–Micro Computer: System Variables Comparison Chart

Sometimes when you've written an application for the ZX81 or ZX Spectrum you wish to port it to the other, or even back to the ZX80. Sometimes you've used a system variables and you need an easy reference chart to look up correct system address on the target system and move on. But you say, there is no chart, or there was no chart until now.

I got tired of looking through the manuals every time I need to check some System Variable values and decided to just put them all in a chart. Hopefully you might find it similarly useful. A PNG graphic is available below, and if preferred a PDF version can be downloaded.

If anybody notices some glaring or even slightly disturbing error, let me know and I get them ironed out and fixed up.

One final thought, It's quite interesting to see just how many changes were made to the ZX line of computers in the space of 3 or 4 years. There are the obvious physical differences of course, then there are changes witnessed in the System Variables above.

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RetroChallenge 2017/10: Part 8

Keyboards Down on the NEC PC-8401 Challenge.

Sadly it's time to put the keyboard away on the RetroChallenge for October, but not before a quick summary. And did I mention the keyboard yet, it would be remiss to not to.

The PC-8401 has a truly wonderful keyboard, seriously it's a beauty. It seems that particular computer I ended up with has seen very minimal usage. The Alps SKFL series switches are in a fantastic condition, there is no grainy or worn out feel you'd associate with a 40 year old board. The keys themselves are double shot and feel very firm to type on. It would be nice if you could such a keyboard on a laptop today.

Some Closing Thoughts

I think I got to know the PC-PC8401 quite well over the past months activities, with the device proving to be quite a sturdy piece of kit and generally fun to work with. I've still got some more to do though, the big one being the scanning of the remaining manuals for the Internet archive.

Way back at the start I looked what the reviewers has to say on the NEC-PC8401, the major take away criticism being the neglect-ion to include BASIC in ROM. After playing around with the computer over the past month, that point is still a valid one, and hampers the retro usability of the machine, mostly due to memory constraints of adding BASIC to RAM.

Regardless of the above minor issue, the PC-8401 is a fun little device and it'll continue to sit on my desk and or lap for a while to come. I'm looking forward to finding some good uses for it outside the time constraints of the RetroChallenge and I'm certainly going to plan some future projects around it the  PC-840.

That's it for RetroChallange 2017/10, thanks to all involved and particularly to all the other projects, it maks very varied and fun experiance. Now it's back to our regular non-programed blogging experience.

See RetroChallenge Intro, Part 1, Part_2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8

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