Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!yale!cmcl2!lanl!beta!egdorf From: egdorf@zaphod.lanl.gov (Skip Egdorf) Newsgroups: comp.arch Subject: Re: VAX and VMS development (was Re: Graphics Primitives) Message-ID: Date: 21 Nov 90 23:05:38 GMT References: <11030@pt.cs.cmu.edu> <42992@mips.mips.COM> <513@ctycal.UUCP> <1990Nov21.191759.23254@Think.COM> Sender: news@lanl.gov Organization: Los Alamos National Laboratory Lines: 34 In-reply-to: barmar@think.com's message of 21 Nov 90 19:17:59 GMT In article <1990Nov21.191759.23254@Think.COM> barmar@think.com (Barry Margolin) writes: > > In article <513@ctycal.UUCP> ingoldsb@ctycal.UUCP (Terry Ingoldsby) writes: > >Aren't you forgetting one of the most successful symbiotic relationships? > >I speak of VAX/VMS. > > Could you give examples? While it's quite likely that you're right about > the hardware and software people talking to each other during the > development (if you're going to implement a proprietary OS specifically > targeted at your new hardware architecture, this is the right way to do > it),... > > Barry Margolin, Thinking Machines Corp. > > barmar@think.com > {uunet,harvard}!think!barmar DEC made a big thing when the VAX was announced about how the hardware and software folks had all crawled into bed together. This can be viewed as both a blessing and a curse. Bill Joy once went into great detail in a bull session at one of the Unix User's Group meetings about problems with 3BSD getting onto the VAX. One particularly nasty one was (I seem to recall) the "tape splatter problem" where one of the massbus registers on the 1/2" tape controller would bleed over into the word-counter when a tape error happened (as they do silently and correctably on 1600 and 6250 bpi drives) causing the tape read to run away. After digging through the sources, they found that VMS mapped the tape's buffer into its on little world and the NORMAL termination was the page-fault caused by running off the end of the buffer. It took a stand-alone Macro program to convince the DEC folks that there was a problem. This is an example of VMS covering up a problem with another problem. These bug/anti-bug pairs can be the bane of one's existance at times. Skip Egdorf hwe@lanl.gov