[Coco] Interesting problem with multi-pak and CC3 and OS9L2 / Nitros9

John R. Hogerhuis jhoger at pobox.com
Fri Sep 30 15:54:14 EDT 2016

I have an interesting problem with my multi-pak.

Back in 90s when I did most of my color computering I did not own a
multi-pak. At some point I bought one off ebay. I have already done the
PEEK to verify that it has the PAL upgrade. It seemed to work fine for
switching between rom paks.

Now that I have a CocoSDC I finally got around to doing some serious
testing and basically with multi-pak, the keyboard doesn't work under OS9.

My keyboard works fine under DECB. But if I boot into NitrOS9 or OS9L2 then
everything locks up at the prompt if I have my disk controller connected
through the Multi-Pak.

Also the cursor disappears.

This does not happen if I connect a disk controller directly to the Coco 3
and boot OS9 that way. Keyboard, cursor work fine in that case.

Now, if I boot OS9 with Multi-Pak in the loop and then power off the MPI
once everything is booted the cursor reappears and I can type (can't do
much though since the disk drive becomes inaccessible with the multi-pak

So is the keyboard handled differently under OS-9? Is it somehow more
interrupt driven? And what could be happening with the Multi-Pak that would
prevent the keyboard from being polled?


-- John.

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