from
Jargon File (4.4.4, 14 Aug 2003)
micros~1
An abbreviation of the full name {Microsoft} resembling the rather
{bogus} way Windows 9x's VFAT filesystem truncates long file names to
fit in the MS-DOS 8+3 scheme (the real filename is stored elsewhere).
If other files start with the same prefix, they'll be called micros~2
and so on, causing lots of problems with backups and other routine
system-administration problems. During the US Antitrust trial against
Microsoft the names Micros~1 and Micros~2 were suggested for the two
companies that would exist after a break-up.