Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!cs.utexas.edu!uunet!crdgw1!crdos1!davidsen
From: davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr)
Newsgroups: comp.unix.xenix
Subject: Re: Resolution of >1024 cylinders question
Summary: Why the MS-DOS restriction?
Keywords: xenix, hard disk, cylinders, ESDI, 1024
Message-ID: <638@crdos1.crd.ge.COM>
Date: 29 Sep 89 15:20:35 GMT
References: <13569@well.UUCP> <751@pmafire.UUCP> <5563@seac.UUCP> <6191@viscous.sco.COM>
Reply-To: davidsen@crdos1.UUCP (bill davidsen)
Organization: GE Corp R&D Center
Lines: 37

In article <6191@viscous.sco.COM>, rosso (Ross Oliver, x537, ionesco) writes:
|  Because of the increased demand for support of large disks, we are
|  changing this policy.  SCO XENIX (and SCO UNIX) will support hard
|  disks having more than 1024 cylinders provided the following three
|  conditions are met:
|  
|  - The disk does not have an MS-DOS partition.

  I thought I'd done this... the DOS partition was the lowest, on tracks
1-49 or so for something the "boot: dos" could handle, and the xenix
partition was above that up to 1224 (I don't have the disk anymore, I'm
best guessing). There were three f/s in the Xenix partition, /, /u, and
/usr/spool).

  Am I misremembering that I did this, or are there cases in which you
can have DOS, too? Remember, you said the >1024 wouldn't work, either.
|  
|  - The disk controller supports the required number of cylinders.
|  
|  - If the disk is the boot device, the kernel, /xenix, must reside
|    completely within the first 1024 cylinders.  The safest way to
|    avoid this particular problem is to use the area above cylinder
|    1023 as your swap area or second file system.

    I definitiely did that.
|  
|  No software changes are necessary, this is the way SCO XENIX currently
|  behaves.  The release notes are being rewritten for the next release
|  to include this information.

  Will this be listed as an enhancement when SCO offers a chance to
upgrade? ;-)
-- 
bill davidsen	(davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen)
"The world is filled with fools. They blindly follow their so-called
'reason' in the face of the church and common sense. Any fool can see
that the world is flat!" - anon