Starting over with 8" drive on PC

[Bob Shannon]

Head load timing problem??

----- Original Message ----- 
From: "Vintage Computer Festival" <vcf at siconic.com>
To: "Classic Computers Mailing List" <cctalk at classiccmp.org>
Sent: Friday, March 25, 2005 11:49 PM
Subject: Starting over with 8" drive on PC


>
> Ok, starting over here since there's been a long hiatus since the last
> time I messed around with this.
>
> I'm experimenting with different 8" disks trying to figure out what's
> going on.
>
> First, the basics: I know my controller can handle FM because I was able
> to successfully copy all the files off an old 160K PC disk in my 1.2M
> 5.25" drive.
>
> Second, the 8" drive can successfully format/read/write an 8" drive when I
> have the BIOS configured for a 5.25" 1.2M drive.  My drive is a Tandon TM
> 848-02.  Someone e-mailed me a link to the manual they scanned, and now I
> can't find that person's e-mail nor remember who it was (I'm so sorry!)
> But at any rate, of the 3 measley links that come back from Google, I see
> that this drive is DSDD.  Still don't know if it can do FM however.
>
> I have some 8" disks in both CP/M and DOS 2.11 format from my NEC APC.
> They both read fine on the NEC APC.
>
> I'm trying to read targeted sectors using debug.
>
> With the CP/M disk, I try to L 0 0 0 1 (Load at address 0, drive 0, sector
> 0, 1 sector) and get:
>
> Not ready reading drive A
>
> Ok, so I try L 0 0 1 1 and after a longer pause get:
>
> General failure reading drive A
>
> Hmm, I'm still new to this, but this seems like a density issue.
>
> Tried on the DOS 2.11 disk and got the exact same errors on both read
> attempts.
>
> I formatted an 8" disk under DOS, then tried L 0 0 0 1 from debug and
> successfully load the sector into memory.
>
> What's interesting is if I try to read sector 0 from the NEC DOS disk and
> get the "Not ready reading drive A (Abort, Retry, Fail)" error, then
> immediately put in my known readable formatted DOS disk and hit R)etry, I
> get the same error ("Not ready reading drive A").  If I abort and then
> retry, it works fine.  Or if I wait at the Abort, Retry, Fail prompt for a
> little while then retry, it also works.
>
> Hmmm....
>
> -- 
>
> Sellam Ismail                                        Vintage Computer 
> Festival
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