DOS 6.22 upper memory

J

Jrh68uk

Member
I have a few DOS programmes and I like the idea of having a dedicated DOS 6.22 environment for them to run in, just as I did some years ago. So, I set one up under Parallels 6. Everything seems to work OK, except the fact that some things won't load due to memory constraints. I remembered how I used to tweak memory using EMM386.EXE to access UMBs but this will not work under Parallels.

Using MSD it would appear that everything from 640 up to 1 Mb is already in use. So, that would be why EMM386 can't get any upper memory for me to use, then.

At this stage I'm not interested in DOSbox or anything similar; I just want to see if there's any way I can free some upper memory for use with DOS 6.22 under Parallels. Is there any way of doing this?
 
EMM386.EXE and HIMEM.SYS

I noticed that the two mentioned files are available in the DOS software that I retrieved from "www.bootdisk.com". Perhaps you can use them to access more memory.
 
Hi,

I have those as supplied with DOS 6.22. Himem.sys is fine and allows DOS to load high but emm386, although it loads fine, cannot make use of UMBs as it all seems to be full.

I guess my question was to do with whether it's possible to have the Parallels environment not use all of the space between 640k and 1 mb for itself. Are you saying you are able to make use of this area using alternative himem and emm386 files?
 
high memory

Jrh68uk said:
Hi,
Are you saying you are able to make use of this area using alternative himem and emm386 files?
Click to expand...

Unfortunately, no. I was only confirming that you are aware of those tools. I need to learn how to use them before I can try anything with them.
 
OK, I have managed to get memmaker to work, and therefore make use of some UMB, by choosing custom setup and then telling it to use the monochrome display area. That has freed 25K or so, which isn't bad. I don't yet know whether it will stop anything from working properly, though.
 
It's been ages since I last used DOS in Parallels but if I remember correctly, Parallels doesn't virtualise the UMB fully. Something to do with real mode vs protected mode. I don't know the specifics but long story short, the full UMB isn't available.
 
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No, I've not tried it but I don't actually need it. I was just trying to set up the DOS environment that I used to have, for sentimental reasons :)

Thanks anyway. I'll bear DOSbox in mind as it probably is more practical.
 
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