Re: Looking for a Micro SCI disk controller

[Eric Smith <eric-no-spam-for-me@brouhaha.com>]

"Bill Garber" <willy46pa@comcast.net> writes:
> So, basically, if I have the 0027 and 0028 proms, I can read
> and write both 13 and 16 sector disks, so why would I want
> the older ones?    8)

The only reason would be if you wanted to boot 13-sector disks without
using BASICS or BOOT13.

Before I did the double-size-boot-prom-and-switch hack, I kept
two Disk ][ controllers in my machine.  In slot 6 I had P5A and P6A.
But in slot 5 I had P5 and P6A.  If I wanted to boot a 13 sector
disk, I just put it in S5D1 and used "PR#5".  But all four of my
drives worked fine for 16-sector because both controllers had P6A.

> Let me check, I have a box full of Disk II controllers and
> some of them wouldn't read 16 sector disks, I wondered why.
> Could be they have the older roms.

If you found a spare 13-sector controller for me, that would be great!

> Good luck finding the chips. I couldn't even find
> data on them, anywhere!

They've been discontinued for at least ten years, but there are still
old stocks of them here and there.

> What do you burn those with?

Old PROM programmers (1970s-1980s vintage).  The Data I/O Model 19,
29, and 29B were quite common.  I've got a Data I/O Unisite, which is
a somewhat later, fancier programmer that can do almost anything.

Best regards,
Eric