@crazyc, the level of accuracy you're reaching is truly amazing - thank you!!!
On the real PC-D represented by the "b6188-pcd-gem" harddisk image, there is a copy of Turbo Pascal 3.0 and a PC-D graphics library.
The PC-D tries to load Turbo Pascal, but then throws an NMI:
This is its normal behaviour for programs that are expecting features from a "real" IBM PC. Confirm with "J" twice, and the PC-D loads Turbo. If you press "N" it will reboot.
There is something weird going on on the real PC-D as well, as I cannot edit a file - the text is hidden behind a grey screen, but I can move the cursor around.
"w" loads the work file - in this case a graphics demo from the graphics library in c:\tp_pcd\circle.dem
"r" compiles and runs the demo, but not before ...
another nmi warns us (twice) that something is not quite right
The emulated PC-D simply dies when you load turbo.com, regardless of the screen configuration in tinst.com (which runs fine).