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...).
Xerox chose CP/M for the computer because of the large software library for the operating system. Dealers reportedly were pleased to sell a computer from a well-known Fortune 500 company but the Rosen Electronics Letter unfavorably reviewed the 820 in June 1981, describing it as a disappointing, "me too" product for a leading technology company like Xerox. In November it stated that the new IBM PC was much more attractive.