[syslinux] chainload back pxelinux from Grub4DOS?

[Miller, Shao]

-----Original Message-----
From: syslinux-bounces at zytor.com [mailto:syslinux-bounces at zytor.com] On
Behalf Of Frantisek Rysanek
Sent: Sunday, December 20, 2009 15:32
To: For discussion of Syslinux and tftp-hpa
Subject: Re: [syslinux] chainload back pxelinux from Grub4DOS?

Dear Mr. Anvin,

thanks for your very precise response to my message,
and thanks for the great job that you're doing on Syslinux :-)

Frank Rysanek

-----Original Message End-----

For what it's worth, if you use gpxelinux.0 from Syslinux 3.84 and
MEMDISK along with "keeppxe", I would expect that gPXE would provide the
PXE stack to whatever DOS you boot.  You could write a trivial DOS
program to invoke gPXE's PXENV_FILE_EXEC PXE extension to return to
gPXE.  As a test, you could write a DOS program to invoke this API call
with the gPXE command

boot pxelinux.0

which should start your PXELINUX menu process all over again.

Note that any time DOS has started up and established INTerrupts and
looked at hardware, it's pretty risky business trying to go backwards
and then forwards again to some other OS without a proper reboot, which
allows BIOS to set things up as they are expected to be by OS startup
processes.

H. Peter, I believe that you've mentioned that the newest gpxelinux.0
will move out of the way for NBPs and kernels (such as MEMDISK).  So in
this instance, a newer gpxelinux.0 -> MEMDISK would not leave gPXE's PXE
extensions intact, is that correct?

Thanks for your time,

- Shao Miller