If you already have 635KB free I don't see a point in continuing further. In practice 600KB is about enough. Quickly checking the threads here it appears about 618KB-620KB was what the largest games needed, and even back then a game that required that would be seen as an exceptional PITA and you'd probably use a dedicated boot disk or dos menu config for it.

Beyond just unloading unneeded stuff and using more sophisticated memory managers than what was bundled with MS-DOS (as you've done already), something available now but more difficult back then is replacing drivers and TSRs with something else that does the same thing but is more memory-efficient, and you've already done that too. In addition, Win95 DOS boxes are a trade-off in that the maximum possible free memory is lower, but certain drivers aren't needed at all like a mouse driver or MSCDEX, so fewer moving parts in freeing memory.

At some point if you do what you'd need to achieve more than you have already, you have a system that is no longer 100% IBM-compatible or breaks compatibility with MS-DOS. The vidram trick is already not IBM-compatible.

There are certain data structures at the bottom of conventional memory that take up a few KB and simply can't be moved.

Without any tricks on your system, do you have the full 640KB conventional memory? Some "modern" (late 1990s) BIOSes are of the sort that always steal 1KB of conventional memory to stash certain things and you can't do anything about it, so you could always just use a system that doesn't do that to prioritize your DOS gaming. Or is this an emulator; I can't tell.

Up to ca. 900 KB are possible without a graphics card.
MS-DOS then has to be "remote-controlled" from a serial terminal, via CTTY command.
That configuration was useful to compile large projects using compilers that didn't support XMS or EMS yet.

Edit: With CGA graphics, 736 KB of conventional memory are possible.
PC/XT users used this configuration once (in DOS 3.x days).
But they had to because they didn't have HMA (286+, DOS5+) to outsource DOS to.
An UMB card was technically available to them, but I'm not sure if they used it.
OS/2 can provide 736 KB, too, by limiting applications to CGA.

PS: In order to gain more than 736 KB and have graphics the frame buffer either must be relocated which involves well written VGA applications
which ask the BIOS/VGA BIOS were frame buffer location is or applications that support the alternate frame buffer region directly.
Or an exotic graphics card standard with a higher frame buffer region is needed.
Something exotic in the sense of TIGA graphics, PGC, Hercules InColor.
Not them, but something like them. A graphics hardware that has its frame buffer closer to 1 MB border.

Jo22 wrote on 2024-11-07, 21:51:

Up to ca. 900 KB are possible without a graphics card.
MS-DOS then has to be "remote-controlled" from a serial terminal, via CTTY command.
That configuration was useful to compile large projects using compilers that didn't support XMS or EMS yet.

In practice would DOS software in that situation have been cross-built on a VAX? I think even MS did that for a time

Conventional memory : aiming for the stars , seems a interesting challenge. A baseline configurarion (mouse, cdrom driver ,smartdrive ) could de established and then whoever gets most free memory "wins"

dos_user_since33 wrote on 2024-11-07, 20:59:

1) With Qemm, 4DOS, Dosup, Nnansi, etc. : 635K free
2) With Qemm, 4DOS, Dosup, NNansi, vidram: 729K free

Pretty good amount of memory, how are you did this? Can you please provide zip file with set of configuration files?

Only thing I've seen recently that benefits from lots of conventional is Graphics Workshop for DOS, program uses somewhere around 200k, then what's left is it's working memory, though it does use a temp folder on HDD for extra. Anyway, I guess if you want your 500kb jpeg lewds dithered in CGA glory that you need to scroll around 'coz it's 1024x768, then yeah, getting into the 700s useful.

jakethompson1 wrote on 2024-11-07, 21:54:

Jo22 wrote on 2024-11-07, 21:51:

Up to ca. 900 KB are possible without a graphics card.
MS-DOS then has to be "remote-controlled" from a serial terminal, via CTTY command.
That configuration was useful to compile large projects using compilers that didn't support XMS or EMS yet.

In practice would DOS software in that situation have been cross-built on a VAX? I think even MS did that for a time

Hi, yes, I think they did cross-compile in the 80s.
I read that they had DEC computers with the TOPS-20 OS.

https://www.betaarchive.com/forum/viewtopic.p … fef0bc4#p475168

BitWrangler wrote on 2024-11-08, 14:20:

Anyway, I guess if you want your 500kb jpeg lewds dithered in CGA glory that you need to scroll around 'coz it's 1024x768, then yeah, getting into the 700s useful.

Hey! Who told you about my collection!? 😱

Edit: Seriously, though. Who told you ? 🤨

- Just kidding. 😇

Dithering on CGA sort of is a thing, though.
CompuShow 2000 has a few separate palette drivers for CGA, I think.

These CGA examples are fine, I think.
https://www.youtube.com/watch?v=posl9Qwym_M

This site can simulate different video hardware.
https://8bitworkshop.com/dithertron/#sys=c64. … mage=seurat.jpg

There's also an older thread/topic about it.
Art of CGA

MAZter wrote on 2024-11-08, 14:13:

dos_user_since33 wrote on 2024-11-07, 20:59:

1) With Qemm, 4DOS, Dosup, Nnansi, etc. : 635K free
2) With Qemm, 4DOS, Dosup, NNansi, vidram: 729K free

Pretty good amount of memory, how are you did this? Can you please provide zip file with set of configuration files?

Here are the config.sys and autoexec.bat. Config.sys vrega parameter is for Vidram, without it low dos memory is 635K

I wonder how much is necessary to have so much unused conventional memory for common applications? If I remember right when I asked what is the maximum amount of conventional memory to run any program, someone said about 620kb.
On the other hand, I watched the posted boot files and there is pratically nothing in it, not even ctmouse is loaded, no cd drivers, no sound card drivers, it seems a good show not something usable.

From what I learned it's always a trade off between compatibilty and using alternative programs which has lower memory footprint.

Nemo1985 wrote on 2024-11-10, 00:37:

I wonder how much is necessary to have so much unused conventional memory for common applications? If I remember right when I asked what is the maximum amount of conventional memory to run any program, someone said about 620kb.
On the other hand, I watched the posted boot files and there is pratically nothing in it, not even ctmouse is loaded, no cd drivers, no sound card drivers, it seems a good show not something usable.

From what I learned it's always a trade off between compatibilty and using alternative programs which has lower memory footprint.

Yes, normally. However, there are certain tricks to get lots of conventional memory, even if drivers are loaded.

What comes to mind is using HMA/UMA to upload larger parts of DOS kernal, 4DOS (command.com replacement) or a special DOS that's not mainstream (X- and ROM-DOS etc).

What's also clever is a technology called cloaking by Helix.
Cloaking offloads big drivers into Extended Memory (above 1 MB).

How does it work? In simple words, cloaking leaves small "stubs" for each big program in DOS memory (Conventional Memory or UMBs).
- A cloaking driver, a special memory manager works in tandem with them.

These stubs are visible to DOS and then keep communication with their big brothers in Extended Memory. They're like remote controls, in simple works.

There are even BIOSes which use cloaking technology.

I just tried this so called 4dos (command.com replacement) other than it comes just in english language, after installing it (I didn't mess with the options too much other than load it high), I got 2kb of convetional memory less compared with the dos 7 command.com... other than the different layout but I suppose it's a mater of habits and preference (and probably changeable?).
I always wondered if ansi\nansi is of any use and for what to people which doesn't use english\american keyboard layout.

You made me curious about the helix software, it may be useful with the purpose of using programs more compatible and larger memory footprint, thank you.

Question: the so called helix software can be used with dos 7?

Nemo1985 wrote on 2024-11-10, 02:38:

You made me curious about the helix software, it may be useful with the purpose of using programs more compatible and larger memory footprint, thank you.

Question: the so called helix software can be used with dos 7?

Hi, you're welcome. ^^

You can find more information on it on Wikipedia.
Two software packages using it are/were Helix Netroom 3 and Helix Multimedia Cloaking.

The latter is Windows 95 compatible, so it works on DOS 7.x. And Windows 98, too.
It also has a SmartDrive replacement. I've mentioned it here: Re: Can I skip Smartdrive?

Popular programs using cloaking are Logitech Mouse driver and some builds of MSCDEX.
Some were bundled for free with driver disks for PC hardware.

Fun fact: Microsoft MemMaker in MS-DOS 6.x was based on the Customize application of Helix Netroom 2.x or 3.
https://www.youtube.com/watch?v=NF83dbkuunA

dos_user_since33 wrote on 2024-11-09, 21:26:

Here are the config.sys and autoexec.bat. Config.sys vrega parameter is for Vidram, without it low dos memory is 635K

Great, thanks!