March 20, 2022

Callan Multibus 68k computer - the hard drive controller

This is a multibus board. It is also known as the "CWC" (Callan Winchester Controller). It is also know as a Liberty Bay Computing model WDC-796-A. (Note that 796 is an alias for multibus).

The heart of the controller is a N8X305 "microcontroller" and a gang of six WD1100 chips. This board is an MFM disk controller capable of handling 4 drives. In the Callan, it handles the single 21M Rodime hard drive.

I had hoped to use this as a "black box" without digging into it. I am encountering difficulties with it, and am now resorting to some reverse engineering to better understand it.

Feedback? Questions? Drop me a line!

Tom's Computer Info / tom@mmto.org