6300 Clock & PC-DOS 3.1

[wtm at neoucom.UUCP]

A:  I run AT&T DOS 3.1 without an ethenet card and also without
enet.sys.  I have experienced little trouble with the system clock.
Congrats to AT&T for not having the date rollover bug that so many
other implementations of DOS have.  On many flavors of MS-DOS and
(all flavors??) of PC-DOS, if the first BIOS call after midnight is
a disk operation, the flag that indicated date rollover is lost,
and the date is a day behind at the occurance of the next timer
tick.  Either I have been lucky or this is not a problem on AT&T
MS-DOS.

B:  Possible clock problems.

1.  Sappy batteries cause the clock to loose time.  This happens
when the battery itself poops out, or if the machine is used
infrequently.

2.  It has been my experience that about 3/4 of the 6300s that we
have have a tendency to loose time at about 1 min/day.  You could
try to adjust the trimmer cap. next to the clock chip.  With a
low-capacitacne scope lead, a frequency counter should read
32 768 . 000 Hz.

3.  Resident Diagnostics version 1.43 cures some problems related
to getting goofy times, if the time rolls over while the clock
chip is being read.

4.  Some overly IBM-specific programs are confused by the 6300's
way of keeping the system time-- Norton Utilities, for instance.

5.  This shouldn't matter, but could leaving the ethernet board in
your computer but taking enet.sys out of your config.sys file leave
the hardware on the ethernet controller in a state that keeps the
clock from working correctly?  That is, IF you left the board in.

C:  One of our 6300s is weird.  It stops keeping time when the a.c.
power is off; almost as if the clock oscillator is not running.
The time when the system was shut off is frozen while the a.c. is
turned off.  I haven`t had time to put my oscilloscope to it yet to
see what is going on.

  --Bill

Bill Mayhew
Division of Basic Medical Sciences
Northeastern Ohio Universities' College of Medicine
Rootstown, OH  44272  USA    phone:  216-325-2511
(wtm at neoucom.UUCP   ...!cbatt!neoucom!wtm)