The Model 820 is an attempt from Rank Xerox to enter the professional micro-computer market. But the 820 is a bit weak with its Z80 at only 2,5 Mhz and its 96kb 5''1/4 disk-drives (83k formated). Fortunately higher capacity 8'' disk-drives were also available (300 kb each). Apparently a 10Mb hard-disk was also proposed.
The communication was focused on the fact that the Xerox 820 could suit to a lot of professions, and indeed, thanks to its CP/M compatibility a lot of different software was available (Wordprocessor, Supercalc, AGIS billing, SAARI, Wordstar 3.0, Mailmerge 3.0, Supersort 1.6, Calcstar, Infostar 1.0, FIGARO hair-dresser management, etc...).
Greg Eshelman reports us these tips :
Here is a tip. Most of the drive boxes with single sided drives used a cable with fewer wires than the ones with double sided drives.
All you need to do is carefully move one of the ground wires at both ends of the cable to the side select pin location and you can swap in a pair of ordinary TEAC or Tandon 360k drives. :) For the end that plugs into the 820 you need a special tool for removing and inserting the pins. A tiny screwdriver works on the other connectors, you have to do it on both of the drive connectors.
One "bug" with the 820 series is it cannot tell if the drives are single or double sided and will blindly "format" double sided in a single sided drive. This works until you try to put too much on a disk then it messes up and you lose everything on the disk!
Steve Bolingbroke reports:
Xerox had a proprietory operating system from a previous computer (mini ?) range , called M80 (?). I was part of project team that ported the old O/S to the 820 so that it dual booted and could run business apps writen for the previous range. We got it to work exactly the same except the command lines (reserved bottom two lines of the screen) had a dark stripe between them. We called it the "Go Faster Stripe".
The 820 was compatible with the APPLE II Pascal format. I worked for Xerox from 82 thru 93 and had an 820 on my desk. We took the Turbo Pascal binary from the Apple II and download it via Xmodem to the 820 and it ran very well. We wrote a early BBS with this environment.
Special thanks to Beverly Brown who donated us this computer !
END OF PRODUCTION
BUILT IN LANGUAGE
Basic 80 delivered on disk
AZERTY/QWERTY, full-stroke keyboard with separated keyboard
Zilog Z80 A
from 4 kb to 8 kb
80 x 24
Black and white 12'' monitor
SIZE / WEIGHT
Main unit/monitor : 32,8 x 38,1 x 34,3 cm / 13,6 kg
Serial 9600 bauds, Internal Expansion Slot, External Floppy Connector
BUILT IN MEDIA
One or two 5.25'' disk-drives (80 KB formatted each) One or two 8'' disk-drives (160KB each)