Hi!
Answers are inline, below:
> Actually the 32 or 64 MB limit only affects EMS. If you
use XMS or a 32-bit protected mode DOS extender / DPMI,
you can easily use 2-4 GB of RAM, depending
use XMS or a 32-bit protected mode DOS extender / DPMI,
you can easily use 2-4 GB of RAM, depending
>
Thanks for confirming this! I said something similar on another thread but was (probably) misunderstood. :-)
> You may also enjoy reading about
Cool! Long mode?! no idea this even existed! Will definitely go to the backlog of stuff to study! thx!
> Any other limits you would like to stretch? :-)
haha! This will keep these machines running for a looong time.. Pretty sure that by the time I bump against those limits you guys will have extended it even further :-)
Cheers,
F.
Sent: Saturday, November 28, 2020 at 12:21 AM
From: "Eric Auer" <[email protected]>
To: [email protected]
Subject: [Freedos-devel] Stretching DOS limitations
From: "Eric Auer" <[email protected]>
To: [email protected]
Subject: [Freedos-devel] Stretching DOS limitations
(Reply to a mail in "New Old-Timer Reporting")
Hi!
Actually the 32 or 64 MB limit only affects EMS. If you
use XMS or a 32-bit protected mode DOS extender / DPMI,
you can easily use 2-4 GB of RAM, depending on how much
is reserved for 32-bit access to your graphics card etc.
Recently, Japheth has even modified his drivers to support
his own interface modification "XMS 3.5" which allows to
use even more than 4 GB of RAM :-)
https://github.com/Baron-von-Riedesel/HimemSX/blob/master/XMS35.txt
To demonstrate the idea, Japheth has also provided a
patched version of Jack's RAMDISK which you can now
use with FAT32 sizes of several gigabytes: The SX in
HIMEMSX and RDISKSX stands for Super Extended :-)
You may also enjoy reading about
https://www.codeproject.com/Articles/894522/The-Low-Level-M3ss-DOS-Multicore-Mode-Interface
which allows you to create DOS apps which run on multiple
CPU cores.
Another fun thing would be GPT partition support in the
kernel, for those who like more than 2 TB disk size, but
I would still limit individual FAT32 partitions to 2 TB
and 512 byte logical sector size.
Another topic in the same thread in the BTTR forum is
https://www.bttr-software.de/forum/forum_entry.php?id=17254
which discusses support for file sizes above 2 or 4 GB
by providing the EDR-DOS int 21 function 7142 for llseek:
CL=origin (0 start, 1 here, 2 end) BX=handle and DS:DX
pointer to relative 64-bit offset on call, 64-bit absolute
offset on return, AX and carry for the usual return values.
Any other limits you would like to stretch? :-)
Cheers, Eric
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