gwalker@SPCA.BBN.COM.UUCP (08/03/86)
sys$sysdisk - the history. [Surely I'm not the only one on this list who has been using VMS since before V3! ] I'm not sure to what extent sys$sysdisk is really used now, in vms, but I can tell you what it originally was (in vms 2). sys$sysdisk WAS the disk that the system files were on. We didn't have [SYS0.],etc then at all. There didn't used to be either a sys$sysdevice OR a sys$sysroot. When VMS 3 came along, and putting the system files into roots like [SYS0.] started, DEC defined 2 new logicals, sys$sysdevice and sys$sysroot. They then suggested that one define sys$sysdisk to be whichever of those 2 made things work best on your machine. (The idea was for migration - people were supposed to stop using sys$sysdisk and use whichever of the other 2 were appropriate for their application.) The software package that you received that uses sys$sysdisk may be originally from pre-vms 3 days. I believe, though have no proof, that DEC software (and most others) do not use sys$sysdisk anymore so you should be free to define it to be whichever makes that software run. (If I remember the messages correctly, I think you want sys$sysroot). I don't know if clusters actually USE sys$sysdisk for anything. -- Gail Walker gwalker@bbn-spca
McGuire_Ed@GRINNELL.MAILNET (08/06/86)
>Date: Sun, 3 Aug 86 7:04:24 EDT >From: Gail Rubin Walker <gwalker@spca.bbn.com> >Subject: sys$sysdisk > >... When VMS 3 came along, and putting >the system files into roots like [SYS0.] started, DEC defined 2 >new logicals, sys$sysdevice and sys$sysroot. They then suggested >that one define sys$sysdisk to be whichever of those 2 made things >work best on your machine. (The idea was for migration - people >were supposed to stop using sys$sysdisk and use whichever of the >other 2 were appropriate for their application.) > >... I believe, though have no >proof, that DEC software (and most others) do not use sys$sysdisk >anymore so you should be free to define it to be whichever makes that >software run. ... I don't know if clusters actually USE sys$sysdisk >for anything. SYS$SYSDISK is defined in STARTUP.COM as SYS$SYSROOT, independent of whether one is running a cluster or not. Based on that information and on your enlightening history, my final comments are: - It is awfully strange that it would be missing from someone's system unless they modified STARTUP.COM (naughty, naughty) or removed it themselves. - Even though DEC probably doesn't use it, some older software products probably do use it, so I'm not going to remove it from MY system. Since I can't find documentation on this migration path in the V4 doc set, I'm not going to redefine it either.