Large disks with DOS/Xenix

[Ed Hew]

In article <2092 at hounix.UUCP> chuckb at hounix.UUCP (Chuck Bentley) writes:
>
>I have a 40 meg drive with rll which gives me 60 meg available.  What I
>wanted to do was setup a small 20 meg partition for dos and the rest for
>XENIX.  My primary purpose was to be able to transfer stuff back and
>forth on the hard disk.  Unfortunatly my XENIX wouldn't allow me access
>to dos if it went past the 32 meg boundry.  What I ended up doing was
>setting up the first 20 meg for XENIX, the next 10 meg for the boot
>partition of dos and the rest (30) meg for a second dos partition.  It
>works fine, except that I don't need all that room for dos and would
>really rather give xenix another 20 meg.
>
>If anyone has a better way of setting this up I would dearly like to
>hear about it.

My release notes (SCO Xenix 2.3.1) suggest that some versions of DOS
shouldn't be made larger than 32 megs as trying to exceed that (DOS)
limit can corrupt the DOS ending cylinder.  Also, remember the most
versions of DOS know that no one has drives larger than 32 megs, so
it's not possible to have partitions larger than 32 megs.  [insert
a _real_small_ smiley here].

My docs further suggest that you should always make the DOS partition
*first* at the beginning of your disk, starting at cylinder 1 (not 0),
due to where DOS likes to write it's boot block.  You would then start
your Xenix partition at the beginning of the next (after Dos partition)
*cylinder* (not track) of your h/d.  This helps prevent DOS from doing
silly things like trying to overwrite your Xenix boot block by
"overflowing" it's partition when full.

You can presumably put other DOS partitions anywhere, because they
don't contain any boot info (unverified).  There are rumours that
some of the newer DOS versions allow you to exceed the 32 meg limit,
but I've been away from the wonderful world of DOS for a few years, so
we'll have to leave it to others on the 'NET to comment on this.

		--ed		{edhew at xenitec.uucp}
				{edhew at egvideo.uucp until new maps hit}
>
>		Chuck...

  Ed. A. Hew             Technical Trainer             Xeni/Con Corporation
  work:  edhew at xenicon.uucp	 -or-	 ..!{uunet!}utai!lsuc!xenicon!edhew
> home:	 edhew at egvideo.uucp	 -or-	   ..!{uunet!}watmath!egvideo!edhew
> home:	 changing to:  edhew at xenitec.uucp     [but be patient for new maps]
  # I haven't lost my mind, it's backed up on floppy around here somewhere!