Re: Reading Commodore 900 disks in the 8250 (LP)

From: Santo Nucifora <santo.nucifora_at_gmail.com>
Date: Thu, 11 Jan 2024 08:14:38 -0500
Message-ID: <CAO6+Cm6sTDNJ=r6B=RXNc8xLn0Q07qRVZcqWkgeM7T4D1E9QNg_at_mail.gmail.com>
It's 80 tracks according to the C900 Floppy Specifications document where
it talks about the number of sectors per track.  Document is here:
https://vintagecomputer.ca/files/Commodore/C900/C900%20Floppy%20Specification.pdf

Santo

On Thu, Jan 11, 2024 at 8:10 AM Francesco Messineo <
francesco.messineo_at_gmail.com> wrote:

> On Thu, Jan 11, 2024 at 2:03 PM Francesco Messineo
> <francesco.messineo_at_gmail.com> wrote:
> >
> > On Thu, Jan 11, 2024 at 1:58 PM Santo Nucifora <santo.nucifora_at_gmail.com>
> wrote:
> > >
> > > Just to clarify:
> > >
> > > The 8250/SFD-1001 uses a Matsushita JU-570 or JU-570-2 drive mech.
> The C900 uses a JA-560-012 drive mech and the serial number on mine is in
> the 100s.  I have never seen another drive in the wild.  Other than the
> C900 documentation, I have not been able to find any other info on these
> drives.
> >
> > according to this document:
> >
> https://retrocmp.de/fdd/panasonic/Panasonic_JU-475-4_Service_Manual_OCR.pdf
> > The JA-560 is a 96 TPI drive
> Ok maybe this can be indeed a too quick conclusion, the -012
> additional part number may indicate a different head actuator that
> makes it a 100 TPI drive. Indeed there seems to be no documentation
> about these drives. I would just try to find information about the
> disk format, 80 VS 77 tracks would clarify the issue.
> Frank
>
>
Received on 2024-01-11 15:00:16

Archive generated by hypermail 2.3.0.