Path: utzoo!mnetor!uunet!husc6!linus!philabs!micomvax!ray
From: ray@micomvax.UUCP (Ray Dunn)
Newsgroups: comp.sys.ibm.pc
Subject: MSDos revisited & Re: Standing a PC on Its Side
Message-ID: <874@micomvax.UUCP>
Date: 8 Jan 88 19:52:12 GMT
References: <4334@ecsvax.UUCP> <435@wa3wbu.UUCP>
Reply-To: ray@micomvax.UUCP (Ray Dunn)
Organization: Philips Information Systems Ltd., St. Laurent - Que., Canada
Lines: 52


The ONLY orientation of a hard disk that is normally not recommended, is
upside down, i.e. rotated through 180 degrees from its "normal" horizontal
orientation, or "bottom" of bearing up.  Standing on either side, or on
its front or back is NORMALLY perfectly acceptable.

The restriction is only because of the platter bearing mechanism.
The likelyhood that the orientation will affect the head positioning is
EXTREMELY small (if it did, the disk under any orientation conditions would
be VERY unreliable - e..g. think of laptops etc).

There may be exceptions to this rule, however we have not come across any
in the PC environment.

The above is fact, the following is opinion.

On the subject of MSDos 3.3 and successors, without specific knowledge
currently of Microsoft's plans (and couldn't tell you if I had unless
it was "public" knowledge), but based on prior experience, I would think
it HIGHLY likely that a successor to 3.3 will appear.

I base this on several facts:
3.3 is not fully compatible with PCDos 3.3;
3.3 does not support 1.4Meg 3.5" floppies;
Dos on 'XT' type hardware (including PS/2 Model 30) does not support
multi-density disk drives (720K/1.4Meg 3.5", 360K/1.2Meg 5.25"), and although
the XT hardware/BIOS does not support the 'disk changed' hardware status that
makes the implementation easier, it IS still possible to handle this in no
worse a way (i.e. a kludge) than XT's and AT's currently handle the media check
function on 360K drives.  This will probably be seen soon on non-vanilla
clones (i.e. those whose manufacturers support their own BIOS and Dos
releases) whether or not it is supported by MS;
DosManager is a likely candidate to be bundled with (into??) a future release
of Dos, one way or another.

One fact about 3.3 I have not seen mentioned in these postings: 3.3 is the
first version of MSDos which supports hard disk partitioning (i.e. vanilla
MSDos as supplied by MS).

This means that in many cases, manufacturers of PC's who implemented
partitioning themselves in Dos prior to 3.3, now have a compatibility problem
(it is unlikely that MS has chosen the same partitioning scheme).

To use Dos 3.3 on a disk partitioned using a pre 3.3 Dos, it is probable that
you will have to backup your entire disk, re-partition & format, then restore.


Ray Dunn.   ..philabs!micomvax!ray
Disclaimer: The above opinions are my own, are not necessarily that of my
            employer, a developer and manufacturer of XT and AT compatible
            clones, and to the best of my knowledge, do not contain any
            information proprietory to my employer nor any other organisation.