From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul Crawford (at UoD)" Subject: Re: Interrupt jitter on Kuper Control RTMC48 Motion Control Card? Date: Mon, 30 Mar 2009 17:41:44 +0100 Message-ID: <49D0F648.7000506@sat.dundee.ac.uk> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Sender: linux-msdos-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: linux-msdos@vger.kernel.org We make use of dosemu for antenna control and use the IRQ-5 interrupt line along with the timer-0 interrupts for our own software. Our main reason for keeping with DOS is simplicity - we don't need to change the working software or worry about device driver updates. However, we were keen to move from Windows 95 to LINUX/dosemu due to the great improvement in security (from none to good!) and networking. We find the IRQ-5 hardware interrupt seems to get through pretty reliably, but the timer-0 stuff can go AWOL for over 0.25 seconds at times. We run dosemu with nice level -11 (to prioritise over the X-server) and disable any cron jobs that could take away host time significantly at regular intervals. I don't know about the particular card you use, but the cases where we used stepper motors the hardware controlled the stepping, and only the reaching of set points or detecting of limit/reference positions relied on rapid response from the software. Maybe not much help, but just to share our experience. Regards, Paul -- Dr. Paul S. Crawford Satellite Station Dundee University Small's Wynd, Dundee, DD1 4HN, U.K. Tel: +44 (0)1382 38 4687 The University of Dundee is a Scottish Registered Charity, No. SC015096