Z80Pack CP/M Emulator and NZ-COM

Z80Pack by Udo Munk is a great CP/M emulator.  It will emulate a number of hardware architectures including the Altair and IMSAI systems, but I primarily use it CP/M development environment.  I can quickly write or edit CP/M programs and on my MacBook and then transfer them over to my Kaypro or Z-100 for testing.  My favorite CP/M 2.2 environment to work in is NZ-COM, also known as Z-System.  NZ-COM is sort of like CP/M on steroids.  It adds directory naming, clock support and instant OS footprint rescaling just to name a few.  I have it installed on my Apple II CP/M partition but unfortunately, NZ-COM is for Z80 PCs only so it won’t run on my 8085-based Z-100.  Udo’s guide to installing Z80Pack is straightforward and Classiccmp already has a great tutorial on setting up NZ-COM within Z80Pack, so nothing new for me to add there. 

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Repairing an 8″ Floppy Drive

When I first powered up the Z-100 for testing, everything worked except one of the 8″ disk drives, a Tandon TM848-1E.  The drive light would make three short flashes, then one long flash and was not detected by the OS (neither CP/M nor MS-DOS).  The Tandon manual didn’t list this particular blink sequence error, so I was on my own with diagnosing the problem.   I thought perhaps the stepper motor might be stuck.  Being the second drive of an old 8″ drive system that was in itself part of a hard drive, dual 5 1/4″ drive, dual 8″ drive system made it likely that this drive probably hadn’t seen any activity in at least 25 years.  Since I was going to be disassembling the Thin Line anyway, I decided to give the whole drive system a thorough inspection.

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Z-100 Manuals Scanned and Uploaded

Thanks for giving me time to catch up on my technical journals

Scotty catching up on his technical journals

I’ve finished scanning a batch of the Heath-Zenith technical manuals in my collection, many of which were not previously available online. I’ve also added manuals from other online sources that relate to the Z-100.  What follows is a fairly complete set of manuals that all apply in some way to the Z-100. Some of the manuals will apply to other systems as well but I wanted to make it easy for someone just coming up to speed on the Z-100 to easily access applicable manuals.  The manuals can be downloaded here.

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New Vintage Technology Site Online

It was high time to upgrade the site from hand-scratched HTML code to something more maintainable and scalable.  Most of the original articles have been moved over and the old antediluviandesigns.com domain now points to planemo.org.  Planemo is an astronomical term for a small wandering object outside of a stellar system that is larger than a minor body but not large enough to achieve fusion.  I’l be creating an astronomical projects website in the near future and I think the planemo name was a good choice for both that site and the obscure hobby of retro computing.



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Z-100 Acquired!

Zenith Z-100 PC

My, what big floppies you have!

The Heath-Zenith H/Z-100 PC is a marvel of early 80s computer engineering. First release in September 1982, it contained both an 8085 CPU for CP/M work and an 8088 for IBM compatibility.  I acquired this system from Bill Adney who wrote a number of articles and books for the Z-100 as well as other PCs like the Kaypro.  Bill kept the system is almost perfect working order and also had a treasure trove of original manuals and software that I’m in the process or sorting through right now.  

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Advent TurboROM

Transferring files one a time was getting a little tedious. The Kermit terminal program (there is actually a Kaypro version of Kermit) and QTerm, which also supports the Kermit protocol, both use polling instead of interrupts so I was only seeing around 2400 bps in transfer rates from these programs. It was still convenient to kick off a disk transfer and go get a beer or something instead of manually transferring each file, but it would have been nice to transfer files at a more modern speed. And then I discovered the Turbo ROM.

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Dynaco ST-70 Vacuum Tube Stereo Amplifier

What vintage technology site would be complete without at least one vacuum tube project!

My college engineering experience was during the 1990s and I never got the chance to learn about vacuum tubes or punch cards, or even Pascal for that matter (first years had already switched to C++). Tubes (or valves if you’re British) have been driving electronics since the early 1900s and they’re still used today for high end audio and certain RF applications. They are a wonderfully robust technology, provide unparalleled audio quality compared to most transistor-based designs and they are simply beautiful to behold.

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High Speed IMP for the PCPI SIO Card

IMP is a great little terminal program written by Irvin Hoff and I thought it could use a speed upgrade along the same lines as QTerm. The result was IMP_SIO.ZIP. Imp is much simpler than QTerm. It’s one .ASM file and it doesn’t support Kermit, just XModem and YModem. While only one source file, Imp was actually a little bit more difficult to modify because the author originally assumed that no baud rate would ever be greater than 9600 bps (4 characters). I had to re-write the baud rate table to support variable length baud rates in addition to inlining the patch overlay routines. I once again easily achieved 57600 bps upload/download XModem data rates with my 6 MHz Applicard in an unaccelerated Apple //e. 115k uploads from the Apple II work fine as well but it’s not quite possible to receive at 115k. I think to properly do 115k data transfers both ways on my Applicard (or any CP/M system) will require my own terminal program written from the ground up.

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