Date : Wed, 16 May 2012 08:53:04 +0100
From : jim@... (Jim Hearne)
Subject: Torch discs.
Hi All,
After creating a DOS bootable USB memory stick, I eventually determined that
my motherboard does indeed not support a second floppy drive.
As soon as i fitted another 5.25" connector to the end of the cable i was
able to access it as drive A.
The Bios didn't support setting the floppy as a 5.25" capacity so i couldn't
get it to work in omniflop in windows.
But, Imagedisk runs happily from DOS.
I've read some of the discs without errors, the only bit left to work out is
if they are 40 or 80 track.
The discs are labelled as Double sided/double density though Imagedisk says
they are Single density after it's tests, does this sound likely ?
It happily reads the disks when set to 40 or 80 tracks, the drive has a
switch for 40 or 80 track (not labelled) but i think it's in the 80 track
position or when i tried to read 80 tracks it would hit the endstop on the
drive.
How can i be sure if they are 40 or 80 track discs ?
Would a 40 track disc read as 80 tracks have duplicated data for every other
track or would it come up with read errors ?
Many thanks,
Jim
-----Original Message-----
From: Jules Richardson
Sent: Tuesday, May 15, 2012 1:45 PM
To: bbc-micro@...
Subject: Re: [BBC-Micro] Torch discs.
On 05/15/2012 03:01 AM, Jim Hearne wrote:
> Well....
> I took the 5.25" drive out of the BBC external housing, changed the drive
> select jumper to DS1 (as the PC likes).
> Found the correct IDC connector for the 5.25" drive and crimped it onto
> the
> existing floppy cable before the twist.
> Fitted the drive into the PC, put it all back together.
>
> Powered up, went into the Bios to enable floppy drive B, and found no
> options for B drive !!
> It seems that most newer motherboards (this one is about 2 years old) have
> removed support for 2 floppy drives.
> Pretty sure this is just a Bios thing, i doubt if they would have removed
> the DS line from the FDC.
Yes, probably just BIOS (on a somewhat-related note, the BIOS in my main
imaging machine on this side of the Atlantic lacks direct support for DD
5.25" drives). I have seen HP machines which do genuinely lack hardware
support for a second drive, but I don't expect that's common...
Although what's stopping you from temporarily making the 5.25" drive the
first floppy in the machine, purely while creating disk images?
> So far the most likely option seems to be to edit the CMOS ram directly to
> change byte 0x10 to the settings for 2 drives.
> But, changing the byte means changing the CMOS checksum otherwise you just
> get a CMOS checksum error.
> So, i've got to work that out as well.
I do find that modern OSes get in the way of stuff like this; Imagedisk
will let you specify the drive type regardless of any CMOS settings, but as
I mentioned it does run via MSDOS, so it may not be the easiest solution in
some situations :-)
> Otherwise, i may just invest in a Kyroflux USB floppy interface.
Can Kryoflux give you a byte-oriented copy of the disk? My understanding
was that it - like Discferret and Catweasel - worked solely at the
transition level, but perhaps it does come with tools to translate that
into a more accessible format.
Personally I'd ask around on freecycle etc. first and grab a few PCs, one
of which should do the job.
cheers
Jules
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