Syslinux - Jun 2003 - Memdisk lower memory usage

Greetings,

I had a quick question about lower memory usage by memdisk. I've read
through the mail archives and found a couple of posted questions but
unfortunately no answers.  I know the documentation states:

"MEMDISK simulates a disk by claiming a chunk of high memory for the disk
and a (very small - 2K typical) chunk of low (DOS) memory for the driver
itself, then hooking the INT 13h (disk driver) and INT 15h (memory query)
BIOS interrupts."

However, running mem.exe after booting from my dos hd image via
pxelinux/memdisk and also after booting directly from the original
harddrive, shows that there is 77K less total available lower memory when I
boot using memdisk.

638K total available lower memory when booting from the actual harddrive.
561K total available lower memory when booting the image via memdisk.
BTW, in each case DOS is using 20K, leaving 618K and 541K of free memory
respectively.

Unfortunately, I've got a bios-update .exe that needs approximately
542K-578K lower memory to load, and I'm trying to pxe-boot into dos and run
it.  (Performing this via pxe is a necessity for a client).


I am calling memdisk and referencing the image (8.5MB uncompressed/ 4.5MB
compressed) with no special options in pxelinux.cfg/default.  

label dos
    kernel memdisk
    append initrd=dosboot.img  

I am using syslinux-2.04-1 on RH9 at the pxe server.  

Is this behaviour expected? Is there anything I can do to free up more
memory?  Thank you in advance for any advice you can give.

Respectfully,

Clay Cooper

Clay_Cooper at dell.com wrote:
> 
> Is this behaviour expected? Is there anything I can do to free up more
> memory?  Thank you in advance for any advice you can give.
> 
Your PXE stack is broken, so PXELINUX is unable to free up the memory
used by PXE.

	-hpa

All,

Based on Peter's advice that my pxe stack is broken, I did some additional
testing.  It seems that, with syslinux-2.04-1, the UNDI drivers are not
unloaded from memory with either an Intel or a Broadcom nic.  

However, while running syslinux-1.75, the UNDI drivers get unloaded from
memory using _both_ the Intel and Broadcom nics.

Viewing the changelog shows several Pxelinux/Memdisk changes between these
two revisions.

Below, I am providing all the information I can regarding nics and boot
agents, perhaps someone can take a look at this.  Thanks for your help.


Respectfully,

Clay Cooper
PG Custom Engineering
512.723.5951


_________________________________________________________
Onboard Broadcom BCM5701 Gigabit Ethernet (rev 15)
NetXtreme Ethernet Boot Agent v3.1.11
PXE-2.1 (build 082)

Intel 82544E1 Gigabit Ethernet (rev 02)
IBA GE v1.2.10
PXE-2.1 (WfM 2.0)(build 083)
_________________________________________________________

Syslinux 1.75
Intel PXE boot    -- 635K mem avail
Broadcom PXE boot -- 635K
Direct to HD	-- 638K

Syslinux 2.04-1
Intel PXE boot    -- 560K mem avail
Broadcom PXE boot -- 561K
Direct to HD	-- 638K
_________________________________________________________