Chuck, thank you. I have some useful/less trivia for you. I was able to snag some IBM DOS 4 & 5 from Texas. DOS 4 appears to be IBM for IBM release where the DOS 5 appeared to be IBM for other OEM releases. The documentation in both versions mentions XMA2EMS.SYS and XMAEM.ASYS. DOS 4 disks actually include the files, the DOS 5 disks do not.
I've also discovered today during a YouTube livestream (
) is loading the driver with the string it provides in the documentation causes it to report a failure with the adapter; however if I run Advanced Diagnostics for the AT; 2.07 (which is my understanding is the latest/best version) the card shows up in the option list as option 85 2 MB Expanded Memory Adapter, and have it had it on a test loop for quite a while testing memory, it doesn't report any failure whatsoever.
The syntax I'm using to load the driver is DEVICE=\DOS\XMA2EMS.SYS FRAME=D000 P254=C000 P255=C400 /X:64 (manual says X:64 gives me 1 meg of EMS, I tried it with X:64 and X:128 to get full 2 megs) but I get the same adapter failure on boot, so I wonder, is the driver bad or am I using switches for the driver that are not compatible with my machines configuration. I'll keep playing around with it and see what happens.