Quoting (part of) a msg from you of 27 Dec 1994:

 JdBP>             18.2Hz is the frequency of the "system
 JdBP> heartbeat" interrupt   which drives all thread scheduling in
 JdBP> the system.  54ms is the   "quantum" for timeslicing.  You
 JdBP> cannot get finer resolution than 1   quantum.

JdBP,

Since the early days of OS/2 I have not heard anything else than that the
OS/2 heartbeat is 32 Hz (31.25 ms interval). In a DOS session it may be
18.2 Hz for the 'softhearted'!

Cheers, Rob 
--- timEd/2 1.01+