21 Sep
2014
21 Sep
'14
8:35 p.m.
Chuck,
I have both a CompatiCard II and a CC IV. My plan actually was to use the CC II on a 5160
system which I have the top open all the time. As I understand it the CC II should work as
a secondary FDC in the 5160 without issues. I was going to setup the 8" drive as a
3rd FDD. Does that sound right or am I setting myself up for disappointment? Anything I
need to watch out for? TIA.
-Ali
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org] On Behalf
Of Chuck Guzis
Sent: Sunday, September 21, 2014 6:19 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Using an 8" drive on a PC (WAS RE: "Smartcom II" package
available)
On 09/21/2014 04:54 PM, Ali wrote:
Earl,
Thanks. I saw that (linked through Bill's site). I agree a lot of good
info. The Adaptec card is an interesting choice. I would not have
suspected it to be that capable. I am planning on using a CompatiCard
which does both SD and DD 8" drives. I just need to get my hand on a
nice 8" drive.
Careful that that Compaticard is a CC IV, and not a I or II. As the latter came out
before the 5170, the port conventions are different from the standard AT-type and the CC
IV. You will probably be disappointed if you use the CC I or II.
Regarding Adaptec SCSI cards with floppy controllers. The magic device is the National
Semi DP8473 FDC. It's also present on some Future Domain 16-bit ISA controllers, as
well as Ultrastor and some DTC ones.
One cute trick that I thought I reported on is that the 8473 has fully-decoded 4 drive
support--and is capable of driving a floppy with no added buffering. Just a matter of
bringing the drive select leads out. Both the DTC and Ultrastor controllers do this using
some unused pins on the floppy connector for the added motor and drive selects. It's
quite easy to add a small couple of wires to the Future Domain cards to provide the same
3rd drive (on the same cable) support. The Tulin 3rd floppy driver can be used with DOS.
Naturally, utilities that use direct hardware access don't care about BIOS support or
drivers. E.g., 22Disk and IMD will work just fine with a third drive.
One other interesting tidbit is that some of the DTC controllers have a couple of jumper
blocks to allow 4 drives on the same cable. The gotcha is that drives are all configured
for a "flat" cable and each uses a different drive select. Motor control is the
same for all 4 drives--turn one motor on, they all come on. A fair compromise for
convenience.
--Chuck