[syslinux] Re: Problem with FreeDOS + himem64 + PXELINUX + memdisk

[Patrick J. LoPresti]

Michael Devore <FreeDosStuff at devoresoftware.com> writes:

> MEMDISK appears to give a great deal of printed feedback, based on
> the printf()'s in the code.  Is there a lot of information on the
> screen from MEMDISK prior to the reboot?  IF so, posting that
> information here would be handy.

Yes, MEMDISK prints a bunch of information before booting from the
"virtual floppy".  Here it is:

======================================================================
MEMDISK 2.08 2003-12-12  Copyright 2001-2003 H. Peter Anvin

e820: 0000000000000000  000000000009f800  1
e820: 000000000009f800  0000000000000800  2
e820: 00000000000e0000  0000000000020000  2
e820: 0000000000100000  000000000fef0000  1
e820: 000000000fff0000  000000000000ec00  3
e820: 000000000fffec00  0000000000001400  4
e820: 00000000fff80000  0000000000080000  2
Ramdisk at 0xfe60000, length 0x00168000
Command line: initrd=test.img keeppxe BOOT_IMAGE=memdisk
Disk is floppy, 1440 K, C/H/S = 80/2/18
Total size needed = 1460 bytes, allocating 2K
Old dos memory at 0x8fc00 (map says 0x9f800), loading at 0x8f400
1588: 0xffff  15E801: 0x3c00  0x0ee6
INT13 08:  Success, count=1, BPT=f0000:9d36
old: int13=e1f74d1a  int15=f000f859
new: int13=8f400008  int15=8f400272
Loading boot sector...  booting...
FreeDOS FAT Kernel
[etc.]
======================================================================

Then I see the FreeDOS intro text, the option to press F5/F8, and
ultimately the crash and reboot.

> Also, if DOS Is loaded high and the XMS swapper shell is present,
> try turning them off to eliminate potential side-effects and
> reporting on the results.

If I remove "DOS=HIGH", it works!  Well, mostly.  The keyboard
eventually locks up.  But it appears to work fine as long as I do not
use the keyboard; the boot disk loads network drivers, maps a Windows
share, runs cwsdpmi + DJGPP Perl...

Unfortunately, I need DOS=HIGH because otherwise there is insufficient
conventional memory to run winnt.exe (my ultimate goal).

> A very preliminary look at MEMDISK seems to indicate that it
> directly queries, accesses, and uses extended memory, operations
> which could conflict with an extended memory manager.  MEMDISK may
> be fundamentally incompatible with HIMEM.EXE (the [64] part of HIMEM
> is not an issue here).  Of course it's hard to tell exactly what the
> thing is doing just by quickly scanning the source code.

So I am just getting lucky with fdxms and MS-DOS + himem.sys?
Possible, I suppose.

> However, if you could track down and communicate with the MEMDISK
> author Peter Anvin, and he was amenable, he may be able to answer
> critical questions in a matter of minutes and save a lot of work on
> the part of others.

HPA monitors syslinux at zytor.com, and at least one other reader has an
interest in this.  So I believe this thread is on-topic for both
lists.

Thank you for the reply!  Let me know what else I can do.

 - Pat