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

microfortnight
 n.

    1/1000000 of the fundamental unit of time in the Furlong/Firkin/Fortnight
    system of measurement; 1.2096 sec. (A furlong is 1/8th of a mile; a firkin
    is 9 imperial gallons; the mass unit of the system is taken to be a firkin
    of water). The VMS operating system has a lot of tuning parameters that you
    can set with the SYSGEN utility, and one of these is TIMEPROMPTWAIT, the
    time the system will wait for an operator to set the correct date and time
    at boot if it realizes that the current value is bogus. This time is
    specified in microfortnights!

    Multiple uses of the millifortnight (about 20 minutes) and nanofortnight
    have also been reported.


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

microfortnight

   One millionth of the fundamental unit of time in the
   Furlong/Firkin/Fortnight system of measurement; 1.2096 sec.
   (A furlong is 1/8th of a mile; a firkin is 1/4th of a barrel;
   the mass unit of the system is taken to be a firkin of water).

   The VMS operating system has a lot of tuning parameters that
   you can set with the SYSGEN utility, and one of these is
   TIMEPROMPTWAIT, the time the system will wait for an operator
   to set the correct date and time at boot if it realises that
   the current value is bogus.  This time is specified in
   microfortnights!

   Multiple uses of the millifortnight (about 20 minutes) and
   nanofortnight have also been reported.