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Re: How to transform a Disk II card to handle 13-sec?

David Empson wrote:

vladitx <vladitx@nucleusys.com> wrote:



Toto,

In any case, full swap of both PROMs will give you a 13-sector
controller. It has been ages and I am fuzzy on everything right now,
but I think you can replace just the bootstrap PROM. Won't hurt to
try, as IIRC the newer sequencer has better margins on reads.



The 16-sector logic state sequencer can definitely read 13-sector disks
(as evidenced by tools like MUFFIN/CONVERT13/BOOT13 included on DOS 3.3
system disks).

I don't recall whether it has any issues writing in 13-sector format,
such as different timing tolerances which might cause issues if the disk
was subsequently read on a standard 13-sector controller.


No, no problems at all.  The newer sequencer is a pure win.


Anyone know offhand which of P5/P5A and P6/P6A is the firmware ROM and
which is the logic state sequencer? (My "Inside the Apple IIe" is still
packed in a box after moving house.)


P5 is the bootstrap ROM, and P6 is the logic state sequencer.

-michael

NadaNet 3.1 for Apple II parallel computing!
Home page:  http://home.comcast.net/~mjmahon/

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