8" drive on PC troubleshooting

From: Vintage Computer Festival <vcf_at_siconic.com>
Date: Mon, 28 Feb 2005 15:24:45 +0000

So I made the adapter cable to connect an 8" drive to my PC. The basic
connections seem to be there. I can actually format a disk from MS-DOS,
at least halfway, meaning the drive goes through the motions of formatting
all 77 tracks but then when it goes to write the directory and other
whatnot it can't move the head back to track 0. The format aborts saying
it can't write the boot sector.

If I then try to DIR the disk the head backs up a track or so but can't
seem to recalibrate to track 0. The head vibrates as if the drive is
sending the signals to the stepper to retract the head but it only manages
to move back a track or so each time I issue DIR. If I do it enough it
eventually gets back to the stop position but it still gets sector errors.

I verified that the drive susbsystem I'm using is good by booting RT-11
off it. I was able to access both drives in the system from RT-11. The
PC system only sees drive B:, or at least when I try to access drive A:
(which is configured in the BIOS as a 1.2M 5.25" floppy, as is drive B:)
it does not engage the head. The notes I used to make my cable indicate
that this might be what I should expect, since it said to jumper the 8"
drive as Drive 1:


"Set the drive to respond to Drive Select 1 (the default for PC drives)"
(under the "Drive links" section).

So I suppose it would make sense that the PC only sees drive B (drive
select 1). Or does it?

Any ideas?

Sellam Ismail                                        Vintage Computer Festival
International Man of Intrigue and Danger                http://www.vintage.org
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Received on Mon Feb 28 2005 - 15:21:13 GMT

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