Osborne-1 SD format

From: Dwight K. Elvey <dwight.elvey_at_amd.com>
Date: Mon Feb 21 18:18:30 2005

>From: "Steve Thatcher" <melamy_at_earthlink.net>
>
>a technical note...
>
>this comment regarding tightly spaced sectors twinged my memory. Anything
>based on the 8272/765 (in other words, all normal PC controllers) was not
>able to keep the "spacing" between sectors as small as the Intel bot slice
>board did. Even the 1793 series was not able to handle this. I had started
>work on a DD Intel ISIS controller back then and did a fair amount of
>research on this back issue. The only controller chip I found that was
>capable of doing both SD and Intel DD was a TI TMX99XX chip (the actual #
>escapes me at this time). The chip had very good control of the bytes
>between sectors and would have been able to handle the small spacing in the
>Intel DD format. Not that this helps Dave's problem, but I figured I would
>throw out the comment because it related in a way.

Hi Steve
 As I recall, the M2FM also had a different sector header.
Unless you could program the header format, just the spacing
problem was only half the issue.
Dwight

>
>best regards, Steve Thatcher
>
>At 01:38 PM 02/21/2005, Dave Dunfield wrote:
>>It's interesting with the Cromemco CDOS disk - the DD area is formatted
>>to 10 512 byte sectors/track, and in the DD(360k) drive, I can't read
>>them at all - For this test, I pulled the actual Teac drive that I have
>>been using on the System-3 (which reads it fine) - it looks like the PC
>>controller has touble with the tightly spaced sectors.
>>
>>Regards,
>>Dave
>
>
>
Received on Mon Feb 21 2005 - 18:18:30 GMT