XPs emulation is pretty flawed.
Do you have EMS in a ntvdm while typing mem at all ?

Qbix: I have the following entries in config.nt:

dos=high, umb
device=%SystemRoot%\system32\himem.sys
files=40
buffers=100
device=%systemroot%\system32\ansi.sys
emm=ram

Opening an XP command window and typing 'mem' gives:

655360 bytes total conventional memory
655360 bytes available to MS-DOS
625840 largest executable program size

1048576 bytes total contiguous extended memory
0 bytes available contiguous extended memory
941056 bytes available XMS memory
MS-DOS resident in High Memory Area

Does this answer your question?

If javelin got released in dos times, it might not see memory above a certain amount 😉

When you modify the properties of a DOS program in XP, you should get a DOS shortcut, which you must use to launch the program in order to gain the modified properties.

Dominus: Javelin was written in a manner which could take advantage of an expanded memory board if one was available - which is presumably why it recognises DOSBox's 'expanded memory'.

ripsaw: yes, I have done this but without success.

if you search this forum, there are a lot of threads about expanded memory under XP. (and fixes)
Usually it involves changing some resources on your PC

Qbix: yes, I have done a lot of searching on this. There seem to be certain PC setups where areas of memory are 'stolen' for various devices thus causing EMS emulation not work. As I said originally DOSBox works for me - I was interested in how DOSBox achieves EMS emulation.

dosbox emulates a full PC. So it has nothing to do with your XP or whatever OS you run.

Does anyone else find it humorous that a bunch of non-Microsoft people can emulate DOS better than Microsoft can?

Paolo_R wrote:

Qbix: yes, I have done a lot of searching on this. There seem to be certain PC setups where areas of memory are 'stolen' for various devices thus causing EMS emulation not work. As I said originally DOSBox works for me - I was interested in how DOSBox achieves EMS emulation.

Have you tried EMS Magic, then?
http://www.emsmagic.com/

Jorpho: yes, but Javelin loads with a message to the effect that expanded memory is not configured properly and ignores it for 'security' reasons.

So DOSBox really does seem to work its magic uniquely!

Have you tried EMS Magic, then?

Just to end this one - I received the following from the developer of EMS Magic in response to my query:

"Unfortunately Javelin is incompatible with EMS Magic, due to Javelin's extensive use of data aliasing.

This means it maps the same logical memory page to multiple physical pages. With a hardware EMS implementation, writing to one physical page will automatically update the other physical pages which have the same logical mapping. However, EMS Magic cannot emulate this in software since it doesn't know when physical pages are being written to, only when they are mapped or unmapped. "

He goes onto recommend a full system emulator, including DOSBox. So DOSBox really does some exceptional things.