A few problems with BSD
Chris Torek
chris at mimsy.UUCP
Fri Oct 7 00:58:28 AEST 1988
In article <10194 at eddie.MIT.EDU> nessus at athena.mit.edu (Doug Alan) writes:
>The following are a few problems I've had with 4.3BSD on a uVax II ....
> (1) If you accidentally attempt to boot a system on a disk drive
> for which there is no partition table in the kernal, BSD kindly
> trashes the filesystem for you.
The 4.3BSD UDA50 driver treats unknown disks as type `ra81'. I
considered this bogus; the 4.3BSD-tahoe driver considers them to
be of type `unknown' (and then gives you a chance to label them).
This does not help much with non-DEC MSCP disks, which generally
claim themselves to be RA81s anyway.
> (2) It appears that the BSD bootblocks will not boot a kernal that
> is bigger than a certain size. This happened to me, and it was
> very frustrating to figure out what the problem was. I finally
> replaced the BSD bootblocks with the Ultrix bootstrap system,
> and this fixed things.
The 4.3BSD bootblock will not work at all on a MicroVAX II. You have
to have been using an old Ultrix bootblock.
> (3) In the partition table for a disk drive, a "-1" for the size of
> a partition is supposed to mean that the partition contains
> everything up to the end of the disk.
Yes.
> It seems, however, that this only works if the disk is less than
> a certain size.
No. Any negative number translates into `reported size - partition
offset'. If the disk reports its size incorrectly, VMS does not work,
so no disks report their sizes incorrectly.
>I also have a more academic question: A BSD filesystem is supposed to
>begin on a cylinder boundary for performance reasons. Is swap space
>also supposed to begin a cylinder boundary, or does it make no
>difference? I know there's "tunefs", and there's tuna fish, but
>there's no "tuneswap"....
It hardly matters, but if everything else starts and ends on a cylinder
boundary, the free region(s) left over for swap space will do so as well.
--
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain: chris at mimsy.umd.edu Path: uunet!mimsy!chris
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