From mboxrd@z Thu Jan 1 00:00:00 1970 From: Clarence Dang Subject: Re: Timing problems Date: Fri, 22 Jun 2007 17:40:42 +1000 Message-ID: <200706221740.44421.clarencedang@yahoo.com> References: <20070620020841.5d5e2274.john@jcoppens.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20070620020841.5d5e2274.john@jcoppens.com> Content-Disposition: inline Sender: linux-msdos-owner@vger.kernel.org List-Id: Content-Type: text/plain; charset="us-ascii" To: John Coppens Cc: linux-msdos@vger.kernel.org On Wednesday 20 June 2007 15:08, John Coppens wrote: > I was trying to install a very old DOS data acquisition program for a > friend of mine (under Linux + DOSEMU), but there seem to be strange > timing problems. > > After many unsuccessful tests (the link with the sensor wouldn't even > come up), I started suspecting timing issues. I booted the machine with a > real DOS disk and sure enough, everything worked. > > I suspect this program uses the DOS 18.xxx Hz timer for its loops. Is the > emulation of the timer under DOSEMU the same frequency? Does it depend on > setting up the 250/1000 tick/s of the kernel? DOSEMU can handle about 100 Hz for the PIT. I have a patch I can dig up that can go up to 250 (or even 1000 depending on the kernel version). It's just a quick hack and not the proper solution though.