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

[dempson@actrix.gen.nz (David Empson)]

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.

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.)

-- 
David Empson
dempson@actrix.gen.nz