Date:	Mon, 21 Feb 2000 08:11:18 +0600 (LKT)
From:	Kalum Somaratna aka Grendel <kalum AT crosswinds DOT net>
X-Sender:	root AT darkstar DOT grendel DOT net
To:	djgpp AT delorie DOT com
Subject:	RE: Accurate timing!
In-Reply-To:	<Pine.LNX.4.10.10002190656170.903-100000@midpec.com>
Message-ID:	<Pine.LNX.4.10.10002210805370.1141-100000@darkstar.grendel.net>
MIME-Version:	1.0
Reply-To:	djgpp AT delorie DOT com
Errors-To:	dj-admin AT delorie DOT com
X-Mailing-List:	djgpp AT delorie DOT com
X-Unsubscribes-To:	listserv AT delorie DOT com

On Sat, 19 Feb 2000, Prashant TR wrote:

> On Fri, 18 Feb 2000, Manni Heumann wrote:
> 
> > It won't work under windows, you should not try to access a floppy drive with 
> > the timer ticking faster, and your system time will be wrong afterwards. 
> 
> Shouldn't try using any disk drive with a modified timer.
> 
> 

If you set the timer faster in a program your system time will indeed run
faster during the apps execution but at the end of the apps execution you
can read the CMOS time (which is unafected) and reset the system time to
it, which should avoid any wrong system times.

BTW this whole issue  can be avoided by making sure that the original
timer interrupt handler is called at the default BIOS rate. 

All you do is program the timer chip to a higher rate but make sure that
the new (ie your) interrupt handler calls the old handler at exactly the
same rate that the BIOS would have done. This will avoid all the floppy
drive related problems also. Any minor system date variations due to the
fact that the old interrupt handler not being called at _exactly_ the BIOs
deafault rate can be avoided by using the CMOS to set the system date upon
termination of the spplication.

Grendel.







Hi, I'm a signature virus. plz set me as your signature and help me spread
:)

- Raw text -