Re: increase base memory

Re: increase base memory

[Stas Sergeev]

Hello.

kandan bala wrote:
> I came to know the dosemu reserves A000 segment
> reserved for graphics.
> Is it possible to shift OR  change another segment
> for graphics.
Ralf Brown memory.lst states:
--------V-MA0000000--------------------------
MEM A000h:0000h - EGA+ GRAPHICS BUFFER
Size:	65536 BYTEs

So it was always there. QEMM have a
program called "vidram", which allows
to use that region as a base memory
by the cost of not being able to diplay
graphics, but vidram will not work
under dosemu because qemm itself doesn't
work under dosemu.

> Is it logically correct.
But how are you running your program
at a pure dos at first (i.e. not
under linux/dosemu)? If your program
works only with QEMM's vidram or something
similar, then your program is broken
at a first place.
Dosemu allows you to use both UMB and
HMA, so there should be no disadvantages
against the pure dos (except that QEMM
with all its wonderfull tricks can't
be used).

> and running a cobol application.
I don't know what cobol was used, but
if it is a MicroFocus cobol, they
provide a DOS extender for it called xm,
wich will let the program to use all
the memory available for DPMI.

Increasing the base memory above 640Kb
is definitely the bad idea, as it is
used very rarely even in a pure DOS
and will cost you the inability to
display graphics.

Re: increase base memory

[Sergey Suleymanov]

>>>>> Stas Sergeev writes:


 Stas> Increasing the base memory above 640Kb is definitely the bad
 Stas> idea, as it is used very rarely even in a pure DOS and will
 Stas> cost you the inability to display graphics.

        By the way, 0.99.13 (pre-1.0) works well with 704k base. ;)

-- 
  Sergey Suleymanov

Re: increase base memory

[Stas Sergeev]

Hello.

kandan bala wrote:
Sorry that I am CC'ing the private
message to ML, but it seems that you
haven't received the message I've sent
you privately, so I'll repeat it here.

> Is any other solutions for memory management.
Do everything that you do in a real dos.
Use XM under dosemu for your memory
management just as you do that without
dosemu.

My previous message (that you obviously
didn't receive) was:
---
Hello.

kandan bala wrote:
 > Yes, The cobol is Microfocus and using
 > XM for dosextender in real DOS.
But then you are making the problems
where they don't actually exist, arent
you?
Just consider dosemu is a virtual DOS
box. You can't use video memory for
RAM in the real dos box (unless you
use vidram, which is weird), neither
you can do that under dosemu esp. if
you are going to display graphics.
I simply dont understand the problem
then, just use XM and you are fine?
---

Re: increase base memory

[Stas Sergeev]

Hello.

Bart Oldeman wrote:
> if you run dosemu in "dumb" mode, well, f000 is even possible, ie., 
> 960k, if you disable EMS too.
Just one question: are we all using
a vidram/memmax here in the real dos?
Or do we already have a dosemu-specific
programs out there?:)
Of course having 960k is cool, and
knowing that dosemu can do something
more than you can do in a real dos is
also great, but what's the practical
use? Oh yes, it will allow you to not
"lh" your TSR's in autoexec, so if the
person knows what he/she do (ie will
not try VGA graphics and write the
useless bugreports later) then why not,
but still I don't see any real reasons.
So if the program requires 960K, then
it might just use XMS/EMS.
As for the original cobol problem, it
turned to be this:
---
Yes, The cobol is Microfocus and using
XM for dosextender in real DOS.
---
and also this:
---
The application
has one option to show the tiff image.
---
So in that case occupying the video
mem is definitely not an option.
And in general I really still see no
practical reasons for that.
Note that under dosemu you actually need
even less resident progs in your memory
than you need under a pure dos, as
dosemu does provide the basic drivers
(ems, xms etc) itself.
But well, if people just think it is
cool that we can do that, then I agree,
it is nice:) Esp in a terminal/dumb modes
where it is also safe due to no graphics...

Re: increase base memory

[John Elliott]

: Ralf Brown memory.lst states:
: --------V-MA0000000--------------------------
: MEM A000h:0000h - EGA+ GRAPHICS BUFFER
: Size:	65536 BYTEs
: 
: So it was always there.

  Well, at least since the EGA. I suppose if DOSEMU emulated an MDA or a
CGA, then it would make sense to use the memory up to B000:0 or B800:0
respectively. On an original XT, it was even possible to do this in
hardware:
<ftp://ftp.simtel.net/pub/simtelnet/msdos/info/896k-mem.txt>
 
: QEMM have a program called "vidram", which allows to use that region as a
: base memory by the cost of not being able to diplay graphics, but vidram
: will not work under dosemu because qemm itself doesn't work under dosemu.

  The same thing is true of DRDOS (the equivalent program is called MEMMAX).

--------m-2F12FFBX0006-----------------------
INT 2F U - DR DOS 6+, Novell DOS 7+ - EMM386.EXE - VIDEO MEMORY SPACE
CONTROL
        AX = 12FFh
        BX = 0006h
        DX = 0000h
        CX = function
            0000h get status of video memory space (MEMMAX /V)
            0001h map memory into video memory space (MEMMAX +V)
            0002h unmap memory from video memory space (MEMMAX -V)

: Increasing the base memory above 640Kb is definitely the bad idea, as it
: is used very rarely even in a pure DOS and will cost you the inability to
: display graphics.

  Except in the CGA modes :-)

-- 
John Elliott

Re: increase base memory

[Bart Oldeman]

On Mon, 16 Dec 2002, John Elliott wrote:

>   Well, at least since the EGA. I suppose if DOSEMU emulated an MDA or a
> CGA, then it would make sense to use the memory up to B000:0 or B800:0
> respectively. On an original XT, it was even possible to do this in
> hardware:
> <ftp://ftp.simtel.net/pub/simtelnet/msdos/info/896k-mem.txt>

right, and this is also true if you run console DOSEMU and lie to it that
you use a CGA graphics card, ie. $_video = "cga", and remove that 640k
check in the parser. Caveat emptor -- your video BIOS might NOT like
this, weird things my happen, and I haven't tried it.

as for xdosemu: it uses vgaemu and I don't think that can be switched off
easily. vgaemu pretty much assumes that it can r/w protect all pages from
0xa000:0 up to 0xc000:0.

Now if you run dosemu in terminal mode you could go up to 736k (b800), and
if you run dosemu in "dumb" mode, well, f000 is even possible, ie., 960k,
if you disable EMS too.

Bart

Re: increase base memory

[Stas Sergeev]

Hello.

Sergey Suleymanov wrote:
> Stas> Increasing the base memory above 640Kb is definitely the bad
> Stas> idea, as it is used very rarely even in a pure DOS and will
> Stas> cost you the inability to display graphics.
> By the way, 0.99.13 (pre-1.0) works well with 704k base. ;)
How "well" did it work? Working without
graphics is definitely not "well" and I
bet some graphics modes should be broken
(if not all). Furthermore the programs
expect the video mem to be where it must
be, so in that case it will just write
to its own memory (corrupting it) trying
to write to a video memory.
This must be rather safe for the text
modes however, so as the text buffer
starts at 0xb000 IIRC.
There is a bug in a parser: it calls
stop_video() for some reasons and it
changes the base mem to 640 when started
under console. This must be resolved
somehow, I guess Bart knows what's
going on there.
But if it would be me, I'd just disallow
more than 640Kb by erroring and terminating
dosemu right away.
I haven't got an answer yet, why is this
really necessary? Are you always using a
"vidram" under real dos? I guess you are
not, but then why should that be used under
dosemu? That's weird and unsafe, why anyone
should be willing to do this? You can use
UMB and HMA, is it not enough?
Well, if that is just a comparison with
0.99.13, then you are right, there is a bug
in a parser.y.in now which must be fixed,
but that still doesn't mean that >640 should
be used on a regular basis after this is fixed.

Re: increase base memory

[Sergey Suleymanov]

>>>>> Stas Sergeev writes:

 Stas> should be willing to do this? You can use UMB and HMA, is it
 Stas> not enough?  Well, if that is just a comparison with 0.99.13,

        Of course it is.

-- 
  Sergey Suleymanov

increase base memory

[kandan bala]

Hello,
  I am using dosemu-1.0.1.0 and running a cobol
application. The application quits when I selected
some options, like F1-HELP due to insuffecient base
memory. I changed the xms,ems and dpmi memory also.
There is no use. Then I set base memory to 704Kb and
the program running well in text mode. If I run xdos
OR dos -X then dosemu quits with sigsegv.
ERROR: general protection at 0xae580: c6
ERROR: SIGSEGV, protected insn...exiting!
I came to know the dosemu reserves A000 segment
reserved for graphics.
    Is it possible to shift OR  change another segment
for graphics.If so, I get 64K additional base memory.
Is it logically correct.I am expecting help to get
more base memory.

Regards 
Kandan




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