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From: John.R.Lyman@cdcnet.ahse.cdc.com
Newsgroups: comp.os.cpm
Subject: Reply to Big Board II
Message-ID: <901126112316052-MTAVN3*John.R.Lyman@cdcnet.ahse.cdc.com>
Date: 26 Nov 90 04:44:21 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 24

] > The WD1771 FDC controller used in the Big Board is the same as used in
] > the Xerox 820 and is capable of using 5.25" floppies.  What needs to be
] > done is to cut the data transfer rate from the 8" rate (500,000K bps) to
] > the 5.25" rate (250,000K bps) and, obviously, accommodate the 34 pin
] > connector on the 5.25" drive.
]
] Or, you can just grab some 1.2 MB drives from an IBoringM AT. They run at
] 500 KHz, so should work just fine.

  I have a Big Board II, and was looking for some 1.2 Meg DSDD 8" floppy
drives.  I found them to be very expensive compared to 1.2 Meg 5.25" drives.
So I went out and bought a PC compatible (i.e. standard) 1.2 Meg 5.25" drive
and hooked it up to the BB2.  I now have a 1.2 meg floppy drive!  I figure
that a 3.5" drive should also work, but I haven't tried one yet.

  I had two problems, 1) the BIOS was assembled to support single sided
drives only, so I had to change a EQU and reassemble, 2) the 5.25" drives
don't usually provide a READY signal like the old 8" drives did, I just
hard wired this signal to ZERO (this causes a retry during formatting
when you switch sides, and may cause some when the motor has to start up,
but, I haven't noticed any problems.  The 5.25" drive is faster than the
old SSDD 8" drives, and a lot quieter (the motor shuts off too)!

                                John Lyman