The Convergent Technologies AWS Emulated CMI CM5410 Hard Drive hijacks ST-506 interface pins 30-32 (or do they hijack pin 34 also?)

From: Tom Trebisky
Date: Sun, Mar 28, 2021 at 4:08 PM
Subject: More time with AWS
To: Convergent MightyFrame 

I decided to trace signals, working my way back from the MFM drive
through the motherboard wire list to be sure I knew
what was talking to what on the HDC schematic (and hence in the code). 
This will lead to more notes in the code,
right now it is 3 tables on sheets of paper on my desk.

One interesting thing turned up.

They seem to "abuse" DS3 and DS4 on pins 30 and 32 of the MFM drive
cable.  They read these two signals and give 
them their own name DRTYPE0 and 1.  This is suggestive, but let's see
where it leads.