The Xerox 820: Innovative or Not?
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- Опубліковано 2 чер 2024
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Hosted and produced by Aaron Ishmael.
Technical work by Joseph William Lewis.
Aaron, this video caused me to have a flashback to 40 years ago. Then I was a young engineer living in Orange County, CA. At that time (circa 1983) Xerox decided to give up on the 820. Then the so called Big Boards flooded the surplus market. You could buy one for $50. Incredibly cheap. At that time there was a thriving computer hobbyist community in Orange County with several clubs present.
After getting a big board you needed a power supply, disk drive(s), keyboard and monitor. Most of which were also available in the surplus market. I put everything in a nice case, and built a CPM computer which I used for several years. I used a 1200 baud modem to connect to various BBSes in the local area, did word processing, and learned Pascal.
At the time I was an assembly language developer, so working in a higher level language like C or Pascal was new at the time.
Unfortunately I recycled all the Big Board hardware after sitting in my attic for many years. Probably a bad decision but there you go.
Thanks for your content and best regards.
I remember these well from the early 80's, I was an impoverished new grad engineer working with others of the same ilk. My memory of these machines was on the surplus market probably after the peak- maybe 1985. The complete systems were out of my price range but you could buy the main board (the big board) for less than $100. The keyboard was a project, it read rows and columns directly from the switches and had that big connector (before serial DIN or PS2 KB's with a micro in the keyboard). Some of my friends got into them and modified the BIOS so they were Kaypro compatible, CPM standardization was not great but Kaypro's were pretty popular (and local). One other note- Ball that you mentioned as the CRT maker, the old mason jar company, grew into a high tech conglomerate tech company and defense contractor that lives on. Ball Aerospace makes satellites and other space systems. Thanks for the memories.
I had a 'big board' that I built as a kit. The 820 cpu board was not the same thing, it was larger. The Fergerson big board was the same size as a Shugart 8" floppy disk drive, and could bolt on the back of it. I had a real 820 main board as well, I don't remember if I got it as a bare board, or if it was populated with chips. They were being dumped as surplus in the 1980's.
The Kaypro computer was based on the same board design.
That keyboard is so thick I thought it's a wedge computer.
The parallels between AT&T with its Bell Labs, and Xerox with PARC, are quite remarkable. Bell Labs did its most innovative work while being funded by AT&T running a profitable Government-granted monopoly. Similarly, PARC was kept afloat while Xerox was making lots of money off its photocopier patents (another Government-granted monopoly). Once those patents expired, just like with AT&T when its telephone monopoly was broken up, the parent company, and the associated research lab, both lost their special lustre.
I seriously thought the keyboard was the computer itself!😮Thats a huge keyboard!
Compare the height of the keyboard to that of an IBM Selectric. Xerox designed this tall keyboard to plonk down in place of typewriters on office desks designed for typewriters. If you have one of the three models of 820 with single sided drives, it's a very easy hack to put double sided drives in. Xerox sold a different cable for double sided drives. What was different? One additional wire! For single or double sided drives they had two different types of cable made which they'd cut to length to put the connectors onto.
The trick is to take the ground wire opposite the Side Select pin on the floppy drive connectors and relocate it to the other side of the card edge connectors. Then at the end that connects to the computer, relocate that same ground pin to where the side select pin is missing. All the wires are completely separate inside the cables. The grounds only connect at the floppy drives via the ground plane on the controller PCB. With the cable modified you can swap in double sided floppy drives. Of course it's a good idea to get the special pin remover-inserter tools for both types of connector.
Something to watch out for with single sided drives is the disk formatting program *does not test* the disks nor does it do any checking for drive type. So it will 'format' double sided to a single sided drive and like those cheap super fake flash drives and SD cards the Xerox will "write" data to the second side head that's not there. Then when you try reading data back, you get nothing.
On the 820-II (I don't know about the original or the 3rd version) there's a pin header inside for a parallel port. On mine I got the pinout for that and made a ribbon cable to hang a Centronics connector out the back for a parallel port dot matrix printer while a Diablo 630 daisy wheel monster printer was connected to the serial port.
The 3rd model of 820 was 2 computers in one. A CP/M computer with the Z80 CPU and a MS-DOS computer with an 8088 or possibly 8086 CPU. Both could run simultaneously and could be instantly switched between similar to using a KVM switch (but without a mouse). I don't know how the two shared the floppy drives and printer(s).
I built one from a bare board. I still have the build documentation and a bare board or two. Unfortunately I let the system go years ago. I was running two of the large drives and still have system and some programs on disc. The keyboard is simple, I used a standard ASCI keyboard but had to use hex inverters between it and the computer. I do still have a original keyboard.
I wonder why XEROX didn't go with the ZILOG Z800 which could run CPM and programs written for the ZILOG Z800 would be faster as you would not have to write multiply and divide routines.
this was one of my first computers i had the 820 , the 820II-16/8 w/2 8'' dsdd drives. was cool
If I recall, the last byte of the first sector denotes the format of a CP/M drive. That will at least give you some smokescreen as to wether it might be valid or not.
My dad got his first job working on a Xerox 820 Model 2 running CP/M when he was 16 years old. The company was trying to port their software from Unix to CP/M. He ended up working more on Unix than CP/M.
Friends of mine worked for Xerox and he gave me an 820-2 in a custom steel case with two 8" drives to use for a while.
And she had a Star at home.
I remember helping someone setup an 820, they bought it from an electronics clearance outfit (I think Protecto or something similar - was advertised in Computer Shopper) complete system with printer and a full suite of software (Wordstar, Multiplan, BASIC, dBase II, etc.) the price was really good but DOS was way more popular by then. That's about all I can recall.
I remember wanting one of these back in the day but I already had my loaded up Apple II with a Z-80 card to run CP/M. It was one of the top Z-80 & CP/M machines back in its time but as mentioned, it was a bit late to the game with IBM already releasing something that was more powerful, then consider even though Xerox was well-know, IBM was the dominant player in the upper end of computing.
Reminds me of the Z80 system put out by Exxon
If you think about it, the //e and later Apple models had keyboard layouts is remarkable similar to the IBM PS/2, which became the ISO/ANSI. Apple doesn't get credit for influencing today's keyboards.
A better comparison for the 820 would be the 1978 NoteTaker created at Xerox Parc instead of the Alto or the Star. Using three 8086 processors in the same form factor as the future Osborn and Compaq machines, it could have been a PC before IBM's (though the software was Smalltalk instead of CP/M equivalent). An executive traveled from Xerox headquarters to California to cancel the NoteTaker explaining that Xerox had no interest in the microcomputer market.
That is freaking nuts!
Your haircut looks good!
What a great video, I had never heard of this machine before.
I love this kind of content.
The shaved head looks great!
With more pins coming off of the keyboard, I'd venture to guess the keyboard is actually doing less. And the main chassis is responsible for scanning key presses.
Is it text only or some grafix capability?
Are there any games?
Great video on a wonderful early 80's "executive workstation".
I own 3x 820-II's and 2x 820s w/ all the extra fun stuff.
If you want any of the fun external stuff for the 820, known good mods & fixes from the technical manual, and/or the 8088 "co-processor" (with the additional memory daughterboard) if you have or known anyone else with an 820-II... HMU.
Thank you again for all the excellent content!!!
I like the clean look (your head)... suites you.
Try typing A: instead of just A to boot from floppy. It should work.
PS Then try to use the L command ( Load command ) once you switched to Drive A
the 820-2, a later version than yours used the la (Load from drive a) or lb (Load from drive b) command which loads CPM when you have a CPM disk in Drive a or b respectively.
Launching an 8bit CP/M machine for a high price just before IBM launched a 16bit for less money. No wonder they didn’t sell.
CP/M was still pretty popular in the early 80s but there was so much competition with Osborne and many others that would have beat this on price.
@8:59 dubious looking blue electrolytic alert! Hope you're going to give this thing a good service before spending much time running it.
That keyboard must weigh a tonne 😅
oh they really missed thr point. sad to see
Yes Xerox is a forgotten giant of the early computer age. Love to see machines like this that i have never and may never see in person. 👍
Disappointed that you didn't open up the keyboard case to see if there was any reason for it being so huge and, as a result, not very ergonomic.
Now that is an ugly one. No wonder it failed.
Looks like a well engineered tank. What????
It's weird to me that floppy disk controlers are just so fucking massive? WHY? Does it really take THAT MUCH electronics to move a stepper motor, spin something, read a signal from a pickup, amplify and buffer it and send it when told?
If the machine has 64K, the valid address range should go from 0000 to FFFF, not to AAAA.
I was curious about why only AAAA
I really can’t stand the background “elevator” music :/
It’s very annoying.
Where's the mouse? The GUI? Wait, this is an 8-bit CP/M machine? Ewww
GUIs are bloat
@@elimgarak3597 There's nothing special about that machine. It's just a regular micro with the Xerox logo slapped on front. Any company could've built it.
I enjoy your content, but removing the music would make your videos so much better.
I always liked it
i mean the music blends in so subtlety i barely even notice its there while he's talking and doing stuff.