Osborne-1 SD format

From: Dave Dunfield <dave04a_at_dunfield.com>
Date: Sat Feb 19 20:21:54 2005

Thanks Randy,

>Going by 22disk:
>BEGIN OSB1 Osborne 1 - SSSD 48 tpi 5.25"
>SIDE1 0 1,3,5,7,9,2,4,6,8,10
>BSH 4 BLM 15 EXM 1 DSM 45 DRM 63 AL0 080H AL1 0 OFS 3

I keep forgetting about 22disks database... Thanks for
the reminder.

>Remember most PC disk controllers can't handle FM.

I still haven't figured out what is going on ... I have
other disks which have single-density system tracks with
the rest double-density, and they show as single-density
128-byte sectors when I try and do "read id" on them.

It just some disks (like the Osborne SD) which only "read
id" as DD 1024 byte sectors - I can only assume that there
is some difference in the low-level format structure -
perhaps these are not created in a completely IBM 3740
compatible format...

dave04a (at)    Dave Dunfield
dunfield (dot)  Firmware development services & tools: www.dunfield.com
com             Collector of vintage computing equipment:
Received on Sat Feb 19 2005 - 20:21:54 GMT

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