How to install a MFM drive on a 3B2

[Stephen J. Friedl]

Gregory Gulik posts the informative article:
> 
> By popular demand, I'm posting a summary of what I did
> to make a Maxtor 1140 work on a 3B2/300.
> 
> [Before starting, make sure you have the 3B2 Computer   ]
> [Maintenance Manual.  This manual includes the famous   ]
> [idtools diskette which contains the utilities to format]
> [an MFM hard drive and run various diagnostics.  I don't]
> [know what number to call, but the code is 305-395      ]

# ------------------------------------------------------------------------

This manual and disk can be ordered from the AT&T Customer
Information Center in Indianapolis, IN.  It has select code 305-395,
and at press time it sold for about $65.  The AT&T CuIC can be
reached at:

	(800) 432-6600	Continental US
	(800) 255-1242	Canada
	(317) 352-8556	elsewhere

The CuIC takes phone orders with a credit card, and with a
purchase order for qualifying companies.  They have many other
UNIX-related books as well, so be sure to ask for their free
"AT&T Documentation Guide", select code 000-011.

# ------------------------------------------------------------------------

> The drive ID is 11.

Not necessarily.  The drive ID type is a magic number whose only purpose
is to get you a size when doing an /etc/prtconf.  Figure out how big your
drive is in megabytes, and do the following:

	# cd /dgn
	# edittbl -s -l

It will list a bunch of id types and device names.  Most of the device
names will be of the form "HD72".  If you see one of these names that
matches the true size, pick that ID when formatting.  Otherwise you
can add your own entry to the system.  First pick an ID that is otherwise
unused, then do the following (I'm using 0x0f and HD999 as examples):

	# cd /dgn
	# edittbl -s -i
	utility program for edt_data

	Enter subdevice data

	Enter subdevice ID code: 0x0f
				   ^^--- enter unused ID type 
	Enter subdevice name: HD999
			      ^^^^^----- pick anything starting with "HD"
	Enter device name: SBD
			   ^^^---------- this is always the system board

	Enter subdevice ID code: .
				 ^------ this ends the input

	#

Now when you run an /etc/prtconf, it will print "999 megabyte disk"
in the entry.

This is of course a small matter, but it is fun to suddenly have
a 900 MB drive on your system -- fool your friends!

> The interesting "feature" of this drive (maybe others) is
> that it is possible to format it to 1224 cyclinders.  The
> 3B2 however has a limit of 1024 cyclinders.

This is actually a restriction on the idtools formatter, not
on the 3B2 itself.  I know that people have made 1224 cylinder
drives work (but I have no idea how to do it myself).


> 3) Where can I get more terminators?

You might talk to Arnold about this one :-)

    Steve

-- 
Steve Friedl, Resident Wizard  /  friedl at vsi.com  /  {uunet attmail}!vsi!friedl
V-Systems, the VSI*FAX people /  Santa Ana, CA  / +1 714 545-6442v 545-7653 fax

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