Posted in fa.info-cpm we find the following (historic?) message from FJW@MIT-MC:

"Out of today's mail:  Electronics, June 16, 1981:

Under the heading (pg. 33) "Xerox to market personal computer..."
with the announcement of the 820 which most of you may have seen
already, is "... with IBM to follow suit" Called Chess, it is an
8088-based system priced between $3-4K, and includes two DSDD 5-1/4
Tandon floppy drives, a detachable keyboard.  An OS "similar to CP/M"
from Microsoft (IBM Personal Computer DOS), from 64K to 256K RAM, and
a "600-by-400-line" B&W display and able to handle eight colors with a
resolution of 400x200 pixels or four colors at 800x400.  Look for it
to be announced next month and check out Sears, Computerland, and
maybe J.C. Penney."
While Microsoft has been mentioned a few times before, including an intriguing early mention of XENIX, I can confirm this is the first mention of MS-DOS on Usenet.
Comment by joey Mon Jun 20 04:05:34 2011