Computer History: 1979 Heathkit H89 (A Successful Kit based CP/M Computer/Terminal)
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- Опубликовано: 29 сен 2024
- Computer history series video on Heathkit H89! Travel through the rich computer history, this time we take a look at the CP/M machine Heathkit H89 which was sold (for a time) as a computer kit, that one could put together. Decent specs, doubles as a terminal and good quality build makes for an interesting machine.
Heathkit made their first computer, the Heathkit H8 and released it in 1977. H8 was fairly successful for the time and that prompted Heathkit to come up with a successor: the H89. The original price, when it was released in 1979, was $1695.
It worked both as a computer and a terminal. It featured a Zilog Z80 processor, running at 2.0Mhz. This meant it could run the CP/M operating system.
While it lacked a hard disk, it came with one or two floppy disks drives, which accepted 5.25" 102Kb hard sectored disks. Like many computers of the time, it featured a cassette interface as well.
Pretty cool that a keen DIY’r could build their own computer from parts back then
I have the one my father built on the living room floor... don't have the Winchester drive anymore but it does have two soft sectored half height floppies.
Very nice, piece of history. Slightly different than mine then.
It is a piece of history and I have the fondest memories of going to Heathkit with my father on the weekends. I have nearly all the kits he built with the exception of the television with vanished long ago. I need to replace some caps in the H89 though but there is no danger of any of the kits ever leaving my possession.
That is actually two z80 computers in one: The rear most board is the terminal board with a z80 runningit. The boar in front of itis the computer motherboard , run by the second z80.
1/2 height drives ... they just seemed like the coolest thing at the time. Still do!
The first computer I ever used when I was about 7. Wish I still had it.
Running CP/M required the Zero-Memory-Origin option, which was not available until several years after the '89 was introduced. Normally, RAM started at 040.000 (split-octal, or 2000Hex) with the first 8K being the monitor ROM. Heathkit's HDOS used the up-to-56K of RAM in the remaining address space.
I was working for Amdahl Corp in the 80s… the Z90, H89 used a USART comm chip supporting sync and async serial communications. With this I developed a remote maintenance device for the field engineers to diagnose customers V7/V8 mainframe computers … with the dual ports, they would dial into the machine, if they had issues, they would have the senior AMDAC engineer call into their Z90 to either view or control the customers machine to verify or complete the diagnostic… the parts were order and arrived with the engineer ready to fix the machine. We got nearly 100 Z90s with hard drive floppy and printers for a swap of ……… 4meg of v8 mainframe memory… zenith used Amdahl equipment…
Still have mine (Hard Sector), but none of the Boot floppies work. Haven't been able to find replacements.
Way back when I was 16 I built the H88 version of this machine (it had no disk drive ran programs from their proprietary cassette player.) I LOVED that computer and still miss it to this day.
You're right about that keyboard it felt great, although it was (at least mine was) mechanical, with keys that resembled the feel of the Brown-switches of today.
Not sure who the people are that hit dislike but wow... this is wonderful history. I had one of these when I was eight.
It was HDOS/ZDOS Heath/Zenith Disk Operating System) before there was a CP/M MP/M OS for it. I built one/owned several.
Very informative video, thanks for posting! I recently obtained the Zenith Data Systems branded model and couldn't figure out how to open the shell so this video helped.
I still have my old Heathkit from when I was a kid. Still have the games I used to play on it as well. I was wondering if you could explain how to unlatch the top of it. I can't seem to get it unlatched on mine. I'm sure I'm doing something wrong, and I don't want to break it.
He actually explained how to do it at 10:50, you just need to use a screw driver, and pull one latch on each side towards the screen, so that those 2 pins release, and the case opens.
Russian computer?
No, that is an American computer.
@@DigilogueCollection thanks!