MadMax2023 wrote:

Thank you for your replies :) […]
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Thank you for your replies 😀

The theory that the expansion board may not be recognized is interesting !

As a test I tried Monkey Island 2 which is too modern for this PC even with an accelerator, and the game launched well. Of course the scrolling was slow, but it means that the pc should really have more than the memory avaliable displayed by Commander Keen. I don't know how much memory use Monkey Island 2 but certainly a lot more!
I encountered the same issue with Catacomb Abyss, which is from the same team.

@Tayyare : By the way i am interested by your offer to do a 360k image of dos 5.0 in order to try MEM.

Try removing the memory board, and then check what Keen5 reports for Conventional Memory.

MadMax2023 wrote:

640 kb of memory (motherboard + an isa extension board)

Is that an expanded memory (EMS) board (which may require a driver; it's been ages since I've dealt with that) or does it really extend conventional memory? How much RAM is on the motherboard itself?

Try this DOS 5 360KB image - works in PCEM.

It's bare bones with only MEM.EXE, MSD.EXE and MI.COM.

Try running them and post the results.

It may be that memory board that isn't being recognised by Commander Keen - maybe there's a patched version available?

I think i have 256kb on the motjerboard and 384kb more with the card. The card is set to add the needed memory to go up to 640kb. There are jumpers on it to adjust depending of the motherboard amount of memory.

Thank you for the floppy image, i will make a disk (tomorrow now,for me it is late) and i will keep you updated.
😀

I would also say the base memory size of 640k that Checkit displays is not correct. What is your BIOS setting?

As far as I remember you can display free memory with older DOS versions with chkdsk.exe.

Norton Commander wrote:

Try this DOS 5 360KB image - works in PCEM. […]
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Try this DOS 5 360KB image - works in PCEM.

It's bare bones with only MEM.EXE, MSD.EXE and MI.COM.

Try running them and post the results.

It may be that memory board that isn't being recognised by Commander Keen - maybe there's a patched version available?

Another new thing, my Tandon 5"1/4 floppy drive since today is no working anymore, i get error on error, grrr
And i can't boot from the external 720k floppy, nothing is easy in the old computering world.

I changed my drive, made the dos 5.0 boot disk (thanks again for provided it) and here are the results :

It seems i have a normal amount of memory detected, however it seems i have extended memory (see MSD screens), am i right? is it possible to load the drivers into it to inscrease conventional memory ?

By the way the ID Software games are definitively not detected properly the ram available. No luck, fortunately there are others good games.

thanks

I think the extended memory info is a fluke. Only memory you could have on an XT (even with the 286 board) is EMS / expanded memory. But also the amount seems weird (18 MiB).

The 595,360 reported by MI and MEM sound about right! That's what is actually available to your DOS programs.

No XMS, Himem nor 286 protected mode possible with your Orchid Tiny Turbo, since you are missing the A20 gate.

EDIT: This page suggests you only need 565 KiB free memory to run Keen.

https://pcgamingwiki.com/wiki/Commander_Keen_ … em_requirements

Plus from what I can gather the system info of Keen showing the free memory is actually after the game has loaded. Did you try running Keen when booting from the DOS 5.0 disk? Because that showed almost 590 KiB free memory.

Here is Keen5 in DOSBOX with the following settings:

machine=svga_et4000
memsize=16
core=auto
cputype=auto
xms=true
ems=true
umb=true

You should definitely have enough free base memory to run Keen. In all likelyhood Commander Keen uses some funky memory detection routine that somehow fails with your memory board. I searched but was unable to find a solution. It's puzzling because these memory expander boards were fairly common in the early XT era but I guess ID software wasn't concerned about compatibility with older PCs.

Another thing that seems odd is although Checkit shows the full 640K in your original post it also shows that the largest free block is 315K.

MadMax2023 wrote:

It seems i have a normal amount of memory detected, however it seems i have extended memory (see MSD screens), am i right?

18504K? The 8088 can only address 1MB. The 286 and 386SX can only address 16MB. That's clearly an accidental fish! I mean, a fluke!

AlaricD wrote:

That's clearly an accidental fish! I mean, a fluke!

Hello,

i copied the game on my internal MFM hard disk (to save memory because usually i play game from my CF which uses a driver that consums memory), and i booted on the boot disk, the hightest i get is 339 kb in the Commander Keen launcher. But as it is not well detected, i have in fact enough memory and the game is working well.

A nice game because it plays well like a console game with game pad, sound, fast animation, it is something not so common on old PC games for XT.

Thanks all for your help ! 😊

By the way it seems some people here know the orchid tiny turbo, do you know what happens if i change the 286 CPU by a faster one ?