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From: gwalker@SPCA.BBN.COM.UUCP
Newsgroups: mod.computers.vax
Subject: sys$sysdisk
Message-ID: <8608031852.AA00613@ucbvax.Berkeley.EDU>
Date: Sun, 3-Aug-86 07:04:24 EDT
Article-I.D.: ucbvax.8608031852.AA00613
Posted: Sun Aug  3 07:04:24 1986
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sys$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