[syslinux] Request for built-in DOS launch module

[H. Peter Anvin]

On 01/31/2013 09:21 AM, Alexander Perlis wrote:
> To make say a BIOS flash tool available over PXE, my impression is that
> a typical procedure goes like this: modify a generic FreeDOS 1440K disk
> image to contain the EXE and change the AUTOEXEC.BAT to launch that EXE,
> then make the 1440K IMG available on the PXE server. But more recent
> BIOS flash EXE are too large and won't fit on the 1440K, not even 3840K,
> so now we have to look into making a custom FreeDOS ISO image or FreeDOS
> USB stick image or FreeDOS HD image, for which recipes don't seem to be
> readily available. In a changing enterprise environment involving many
> different computer models, you find yourself over time trying to recall
> and repeat these fragile steps of trying to prepare FreeDOS autoexec
> images...
> 
> Perhaps there is already a better way available? But if not, it would be
> wonderful if SYSLINUX had a built-in module that automagically
> accomplishes all of the tediousness described above, e.g.:
> 
> LABEL biosflash
> KERNEL doslaunch.c32
> INITRD flashtool.exe or files.zip or files.tar.gz
> APPEND exec=flashtool.exe
> 
> I would imagine this would do something along the following lines: set
> up a DOS-like environment with an extra drive letter for a growable
> ramdisk, copy the INITRD file or archive (unpacking as necessary) into
> that ramdisk, switching to the ramdisk drive letter, and then launching
> whatever file is listed in the exec parameter.
> 
> Does something like that already exist?
> 

Being a Linux geek, what I do is I use Qemu (or one can use VirtualBox
or whatever) to create a master HDD image as big as you care for it to
be, and then loopback-mount it to copy the files over.

The FreeDOS ISO is actually a disk image that boots using Syslinux and
MEMDISK, so that doesn't really help you a lot, either.

Now, if you "over time trying to recall and repeat these fragile steps
of trying to prepare FreeDOS autoexec images" it is a good hint that you
should script your process.  This is quite easy under Linux once you
have the master image as described above; I don't know how easy it is
under other operating systems, but it might be worth keeping a Linux box
or VM around for.

(This *would* be a good use for a multi-image version of MEMDISK.)

	-hpa