The Jargon File (version 4.4.7, 29 Dec 2003):

Microsloth Windows
 /mi:'kroh?sloth` win?dohz/, n.

    (Variants combine Microshift, Macroshaft, Microsuck with Windoze,
    WinDOS. Hackerism(s) for ?Microsoft Windows?. A thirty-two bit extension
    and graphical shell to a sixteen-bit patch to an eight-bit operating system
    originally coded for a four-bit microprocessor which was written by a
    two-bit company that can't stand one bit of competition. Also just called
    Windoze, with the implication that you can fall asleep waiting for it to do
    anything; the latter term is extremely common on Usenet. See Black Screen
    of Death and Blue Screen of Death; compare X, sun-stools.


The Free On-line Dictionary of Computing (30 December 2018):

Microsloth Windows
Windoze

    /mi:'kroh-sloth" win"dohz/ (Or
   "Windoze", /win'dohz/) A derogatory term for Microsoft
   Windows which is so limited by bug-for-bug compatibility with
   mess-dos that it is agonisingly slow on anything less than a
   fast 486.  Also called just "Windoze", with the implication
   that you can fall asleep waiting for it to do anything; the
   latter term is extremely common on Usenet.

   Compare X, sun-stools.

   [Jargon File]

   (1996-10-08)