Has anybody tried to run 16-bit DOS Doors on a Windows 64-bit system with Synchronet using a modified DOS emulation system called NTVDMx64?

As we all know, 64-bit Windows can't run 16-bit DOS anything (or 16-bit
Windows anything) because they didn't include any 16-bit support in the
design of it. They can only run in 32-bit versions.

But... someone managed to kludge a way to make DOS programs work in 64-bit Windows using a modified NTVDM called NTVDMx64. You can read about it here:

http://www.columbia.edu/~em36/ntvdmx64.html

Supposedly someone was able to hack the source code and inject a way to
make it work.

I tried it on a test Windows 10 pro VM and it *DOES* work for pure DOS
programs when you run a CMD prompt. I did manage to get LORD to run in
local mode.

But... when I tried to make it work with Synchronet, it doesn't work
because (and Rob please correct me if I'm wrong), Synchronet uses a program called DOSXTRN to call up 16-bit DOS doors. It gives the infamous error
message that you can't run a 16-bit application in a 64-bit operating
system (yeah, I already knew that..)

So my question is - how does DOSXTRN actually work? Is it a 16-bit
application or a 32-bit application? Could this be somehow modified to work with NTVDMx64? Or has someone else figured out a workaround?

The whole process intrigues me as I'd really love to run 16-bit DOS doors
in a 64-bit environment. Yeah, I could use DOSBOX or DOSEMU (Linux) but I'd like to try it this way as well.

So anybody have thoughts or ideas? Thanks!

*** Diamond Dave ***

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Re: 16-bit doors on 64-bit Windows
By: Diamond Dave to All on Mon Feb 17 2020 07:56 pm

Has anybody tried to run 16-bit DOS Doors on a Windows 64-bit system with Synchronet using a modified DOS emulation system called NTVDMx64?

Nobody that I'm aware of... before you. :-)

As we all know, 64-bit Windows can't run 16-bit DOS anything (or 16-bit Windows anything) because they didn't include any 16-bit support in the design of it. They can only run in 32-bit versions.

But... someone managed to kludge a way to make DOS programs work in 64-bit Windows using a modified NTVDM called NTVDMx64. You can read about it here:

http://www.columbia.edu/~em36/ntvdmx64.html

Supposedly someone was able to hack the source code and inject a way to
make it work.

I tried it on a test Windows 10 pro VM and it *DOES* work for pure DOS programs when you run a CMD prompt. I did manage to get LORD to run in
local mode.

But... when I tried to make it work with Synchronet, it doesn't work
because (and Rob please correct me if I'm wrong), Synchronet uses a program called DOSXTRN to call up 16-bit DOS doors. It gives the infamous error message that you can't run a 16-bit application in a 64-bit operating
system (yeah, I already knew that..)

A Windows error?

So my question is - how does DOSXTRN actually work?

It's a 16-bit DOS program which calls out to SBBSEXEC.DLL to handle UART and FOSSIL interrupts.

Is it a 16-bit
application or a 32-bit application?

It's a 16-bit DOS program.

Could this be somehow modified to work
with NTVDMx64?

Possibly. No guarantee it'll work or be reliable.

Or has someone else figured out a workaround?

The whole process intrigues me as I'd really love to run 16-bit DOS doors
in a 64-bit environment. Yeah, I could use DOSBOX or DOSEMU (Linux) but I'd like to try it this way as well.

DOSBOX is not suited to doors.

So anybody have thoughts or ideas? Thanks!

PCMike said he had to hack on NETFOSS to get it work with it and there were still issues with socket inheritence (I think). I'll keep an eye on his progress and the suitability/reliability reports.

digital man

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