Csh confusion: #define HZ 100?

[Guy Harris]

> Except that in 4.2, quantities of CPU time are available from the "old"
> system calls ("times", etc.) in ticks of 60ths of a second (not in any
> units based on the system clock - always 60ths of a second) and are available
> from the "new" system calls in *very* nominal units of microseconds.  As
> such, under 4.2 no user-mode program need know the system clock frequency
> in order to interpret values from system calls...

Well, actually, there is one mechanism that does supply time in system clock
ticks - the "profil" facility.  Somebody just posted a bug report that
"profil" works in clock ticks, which are now 1/100 seconds on the VAX, but
the "prof" command still thinks profiling works in 1/60 second units.

How many systems out there have clocks run off the line frequency rather than
off, say, a crystal?  Systems running off the line frequency would either have
to 1) always supply this time in some nominal units which need not be the unit
of the system clock, 2) provide a facility by which a program can ask the OS
what the system clock units are, or 3) supply different versions of a lot of
the user-mode software in countries with different line frequencies.  Systems
with programmable clocks wouldn't have this problem.

	Guy Harris
	{seismo,ihnp4,allegra}!rlgvax!guy