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From: rmtodd@uokmax.UUCP (Richard Michael Todd)
Newsgroups: comp.os.minix
Subject: Re: Interesting problem with timer (doc'n and impl'n)
Message-ID: <639@uokmax.UUCP>
Date: Thu, 6-Aug-87 17:30:35 EDT
Article-I.D.: uokmax.639
Posted: Thu Aug  6 17:30:35 1987
Date-Received: Sat, 8-Aug-87 15:15:26 EDT
References: <9@ipmoea.UUCP> <4345@felix.UUCP> <1553@botter.cs.vu.nl>
Reply-To: rmtodd@uokmax.UUCP (Richard Michael Todd)
Organization: University of Oklahoma, Norman
Lines: 30

In article <1553@botter.cs.vu.nl> ast@cs.vu.nl (Andy Tanenbaum) writes:
>In article <4345@felix.UUCP> zemon@felix.UUCP (Art Zemon) writes:
>>In article <9@ipmoea.UUCP> ericr@ipmoea.UUCP (Eric Roskos) writes:
>>+ 
>>+ For a good while, I've noticed that after working with Minix and then rebooting
>>+ DOS, the date and time on my machine would be wrong.  
>
>The IBM clock speed is completely programmable.  MINIX sets it to 60 Hz.  I
>vaguely recall seeing somewhere than MS-DOS sets it to 18 Hz or something
>stupid like that.  If this is in fact true, you should reset it to 18 Hz
>(or whatever it is) when restarting DOS.
It's 18.2Hz, to be precise. 
  I've just checked on my system, and upon booting DOS after being in MINIX, 
the clock runs at its usual speed.  One would expect that the proper timer
values is set in the BIOS startup, but maybe it isn't in some machines.  It
seems to be in mine.  
 On the similar subject of strangeness on rebooting from within MINIX: on
my system, when rebooting from within MINIX, the system will reboot only from
floppy and not from the hard drive.  I suspect this is because the MINIX
kernel trashes the low RAM areas needed by my WD hard disk controller.  Also,
when rebooting from MINIX, the ROM BIOS initialization code doesn't seem to
execute (on my system, the ROM copyright message appears on the screen during
reboot, and the speaker beeps.)  Rebooting a second time (after booting from
the MINIX floppy) works fine.  This is with the MINIX 1.1 kernel; I understand
that the reboot code in the klib88.asm for 1.2 recently posted has a different
reboot routine, but I haven't yet installed it.

Richard Todd
USSnail:820 Annie Court,Norman OK 73069
UUCP: {allegra!cbosgd|ihnp4}!okstate!uokmax!rmtodd