[comp.sys.ibm.pc] Miniscribe 3650 40 MB hard drive compatible with AT&T 6300PC?

eab@cbrma.att.com (E.A.Beer) (06/30/87)

Is anyone using this drive on their PC?  Any problems?  In talking to
the sales rep at Hamilton Avnet (800-521-3387), this disk can be
used with an AT compatible or XT compatible.  

I would like to build a digital audio recorder/editor/processor and
use 30 MB to store the audio while still having 10 Meg for programs.
This is the only 40 Meg disk I've seen available for the straight PC
(as opposed to the AT compatible for which much larger ones are available),
and the price of $471.50 with controller doesn't seem too bad.

			Eugene Beer ---inhp4!cbatt!cbrma!eab 614-860-5668

jr@amanue.UUCP (Jim Rosenberg) (07/02/87)

In article <5850@cbrma.att.com>, eab@cbrma.att.com (E.A.Beer) writes:
> Is anyone using this drive on their PC?  Any problems?

I'm using a Miniscribe 6085 with a 6300 with no problems at all.  I'm not
running DOS on in, though, but I don't see why you'd have any problem.  The
The usual hangup with hard disks on the 6300 is more the controller than the
drive.  The 1.4 BIOS chip will supposedly now handle a WD controller.  I've
used nothing but DTC in my 6300 & it's always run like a champ.

I dunno the head/cylinder layout for the 3650, but if you see it in the
following table you should be fine:

Standard Drive Types for the BXD07 ROM on the DTC 5150 CX

Capaci-| # of  | # of  | Write
ty (MB)| heads | cyl.  | Precomp cylinder
-------|-------|-------|----------------
20	4	612
32	5	733
20	4	612	128
10	4	306
43	5	987
60	7	987
20	8	306
42	5	977
42	6	820
10	2	612
62	7	1024
71	8	1024
80	9	1024
33	6	640

There is a position marked "Reserved for non-standard drives" with an asterisk
to contact DTC for information.  I really don't know anything about this. I'm
not sure about the 5150 CX, but I'm assuming it's like an earlier BX I had.
The switch settings are nothing but a "dumb" set of bits that the controller
snarfs by doing an IN to a specific port.  These settings are used as an
index to a drive table in the controller ROM.  The drive table is read into
RAM, and under DOS there is a vector to it in low memory.  I worked this out
once but don't remember the details -- and the location may be DOS version-
dependent anyway.  In theory, it should be possible to run a non-standard
drive by setting the switches for the closest match with the correct number
of heads.  Then in AUTOEXEC.BAT run a little program which diddles the drive
table in RAM to its correct value.  As long as all programs DOS needs to boot
are within the number of cylinders for the standard drive type, I *think*
this should work.

The Miniscribe 6085 wants write precomp at 512.  I was worried about this
when I bought the drive, but everyone, including a techie at Miniscribe said
I'd have no problem by not using write precomp.  So far I haven't.  Good luck!
-- 
 Jim Rosenberg
     CIS: 71515,124                         decvax!idis! \
     WELL: jer                                   allegra! ---- pitt!amanue!jr
     BIX: jrosenberg                 seismo!cmcl2!cadre! /