Are you loading HIMEM.SYS? In my experience, Win98 seems to automatically load HIMEM.SYS at startup if no memory manager is loaded in CONFIG.SYS. Try "DOS=NOAUTO,NOHI,NOUMB." I'm sorry that I was not all that helpful. 🙁

Harry Potter wrote on 2023-04-08, 19:33:

Are you loading HIMEM.SYS? In my experience, Win98 seems to automatically load HIMEM.SYS at startup if no memory manager is loaded in CONFIG.SYS. Try "DOS=NOAUTO,NOHI,NOUMB." I'm sorry that I was not all that helpful. 🙁

Well that's the problem: It configures the system to use XMS even if I use DOS=NOAUTO and have nothing else in the config.sys. It enables XMS if I rename c:\windows\himem.sys as well, so it's clearly using the code that's stuck inside IO.SYS.

If you (or anyone!) have a config.sys that results in booting 7.10 with no XMS, please add the contents here!

You're using BootGUI=0, right?
And what's the program that reports XMS? Are you sure it's really XMS, and not raw Extended memory?

Grzyb wrote on 2023-04-08, 21:00:

You're using BootGUI=0, right?
And what's the program that reports XMS? Are you sure it's really XMS, and not raw Extended memory?

Bootgui=0 is in the MSDOS.SYS file, yes.

If I use mem.exe I get a response including Extended (XMS), and if I load a program that is incompatible with XMS drivers it complains about the existence of XMS.

Try:

mem/d/p

Normally, you should see "XMSXXXX0 Installed Device=HIMEM".
With DOS=NOAUTO, it shouldn't be there.

Edit: also, with DOS=NOAUTO, entering "win" should fail - "HIMEM.SYS is missing."

Grzyb wrote on 2023-04-08, 22:00:

Try: […]
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Try:

mem/d/p

Normally, you should see "XMSXXXX0 Installed Device=HIMEM".
With DOS=NOAUTO, it shouldn't be there.

Edit: also, with DOS=NOAUTO, entering "win" should fail - "HIMEM.SYS is missing."

Correct on both. So what's the deal with this output from mem?

Memory Type Total Used Free
---------------- -------- -------- --------
Conventional 640K 87K 553K
Upper 0K 0K 0K
Reserved 0K 0K 0K
Extended (XMS) 65,472K 65,472K 0K
---------------- -------- -------- --------
Total memory 66,112K 65,559K 553K

Total under 1 MB 640K 87K 553K

Largest executable program size 553K (566,720 bytes)
Largest free upper memory block 0K (0 bytes)

...and when I boot with device=himem.sys the same command shows 512MB of XMS. Clearly different but also clearly XMS. I feel as if I'm missing something fundamental.

MEM isn't precise.
Try the following code:

1uses dos;
2
3var
4    r: registers;
5
6begin
7    r.ax := $4300;
8    intr($2f, r);
9    if r.al = $80 then
10        writeln('XMS installed')
11    else
12        writeln('No XMS');
13end.

Also, I'm wondering what's that program that refuses to work because it thinks it detects XMS - must be some bugware, as XMS normally doesn't interfere with anything.

I think the same. It's a bit weird.

Himem.sys doesn't mess with anything, as far as I can tell.
EMM386, by contrast, does use V86 and interferes with things. But Himem.sys?

It works on a humble 286 processor and only provides XMS services and access to HMA/A20 handling (this feature can be turned off) .

If applications don't actively look for XMS/Himem.sys, they won't even notice its presence.

Hm. Could it be that the application wants to take control of Extended Memory (not XMS) directly?
If so, Himem.sys has an option to set aside Extend Memory for INT15h access.
The option is /INT15=