Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site wdl1.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!vax135!cornell!uw-beaver!tektronix!hplabs!hpda!fortune!wdl1!jbn From: jbn@wdl1.UUCP Newsgroups: net.wanted Subject: Re: 4.2 BSD Driver For DUP11 Board (IBM Message-ID: <659@wdl1.UUCP> Date: Fri, 23-Aug-85 01:25:34 EDT Article-I.D.: wdl1.659 Posted: Fri Aug 23 01:25:34 1985 Date-Received: Sun, 25-Aug-85 13:16:45 EDT Sender: notes@wdl1.UUCP Organization: Ford Aerospace, Western Development Laboratories Lines: 13 Nf-ID: #R:riccb:-46800:wdl1:5900016:000:677 Nf-From: wdl1!jbn Aug 20 16:54:00 1985 Don't expect too much. The DUP11 is a synchronous variant on the DL11; it has one (1) byte buffering on both input and output, and thus must be serviced every millisecond without fail at 9600 baud. Not only is it a machine hog, there are interrupt lockouts longer than 1ms in 4.xBSD. Some years ago I wrote a driver for this turkey for 4.1BSD for use with UNET. It lost bytes above 600 baud, due to long interrupt lockouts in UNET and other parts of the system. Interestingly, VMS drives DUP11 devices just fine, but VMS has a less interrupt-lockout oriented internal architecture than Unix. You could drive it via a KMC, I suppose... John Nagle