Cathy asks:
> Could someone tell me if the 'showtime' command is based on a software or
> hardware clock?  What is the procedure for accessing information about the
> hardware clock?

SHOWTIME, and 99.999% of all MPE/iX software uses the software clock.

The hardware clock appears to be used by only four infrequently called
routines in MPE/iX:

  pdc_update_gmt_offset
  sys_startup_time
  set_time_correction
  timer_powerfail

(Information developed via <plug> AVATAR Tool from Lund </plug>.)

Normally, MPE/iX reads the hardware clock (and the GMT offset information)
at bootup, and rarely refers to it again.  Instead, MPE keeps track of the
number of timer ticks since then (and it knows how many times the timer
"ticks" per millisecond), so it can track the time in that manner.

Interestingly, all of the hardware clocks I've checked (917, 918, 968) are
accurate only down to the nearest second, although the MPE -> hardware
clock interface protocol supports microsecond resolution.

However, if you're asking about the hardware clock, you may have an
interest in two other time/date issues:

   1) Setting the time from a network source (network time synchronization);

      <plug> ask Lund Performance Solutions about BETIMES's NETCLOCK command </plug>

   2) The Year 2000

      <plug> See http://www.allegro.com/hourglass for the most thorough
      date simulation tool. </plug>

BTW, when you run SHOWCLKS.PUBXL.TELESUP, you get:

  ***   Greenwich Mean Time : TUE, AUG 19, 1997,  7:43 PM   ***
  ***   GMT/MPE offset      : -7:00:00                      ***
  ***   MPE System Time     : TUE, AUG 19, 1997, 12:43 PM   ***

You're expected to set the hardware clock to GMT time, not local time.

--
Stan Sieler                                          [log in to unmask]
                                     http://www.allegro.com/sieler.html