7.1 i386 PXE

Oliver Fromme olli at lurza.secnetix.de
Thu Oct 9 13:17:46 PDT 2008

Jeremy Chadwick wrote:
 > Dmitriy Kirhlarov wrote:
 > > I tryin update my install server. Look like 7.1 i386 pxe boot broken.
 > > My own release build is 7.1-i386-2008-10-05
 > > 
 > > Could somebody test this functionality and confirm or disprove my results.
 > What's broken about it?  What behaviour happens?  Are you aware of the
 > mfsroot bug (see step 7 below):
 > http://jdc.parodius.com/freebsd/pxeboot_serial_install.html

It is a problem with memory management in the boot loader.
I hit exactly the same problem during my experiments with
the graphical boot loader, even without PXE and mfsroot
involved.  The problem is that the btx client breaks and
behaves erratically when it runs out of memory.  By default
it can only use a part of the lower 640 KB of RAM, which
isn't very much, given that the loader binary itself is
already 250 KB, and the gzip decompressor requires quite
some temporary memory for its dictionary.

Unfortunately, debugging these things in the boot loader
isn't exactly trivial.  You can't just load it into gdb
and single step it.

If you want to boot via PXE but still use a gzipped mfs-
root, a workaround is to skip loader.4th and beastie.4th,
and instead boot the kernel directly from loader.rc.
This should save enough memory to get you through.

Best regards

Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M.
Handelsregister: Registergericht Muenchen, HRA 74606,  Geschäftsfuehrung:
secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün-
chen, HRB 125758,  Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart

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