about PXE net boot.

[Rui Zhu]

Hi, there,

I've tried to net boot an X-terminal, which has a Realtek RTL8139(X) PCI
controller (v1.00/990420) but without success.  

It can speak PXE-2.0, so that I first tried to directly load Linux
bzImage (not troubled to tag it yet) via DHCP for a test, but image
seems always too large (... too many packages) to PXE, which requires the
download less than 512K.  Therefore, I think I might load GRUB stage2
first to circumvent this situation and could also get a menu gratis.

I got the GRUB v0.91 and configured it with --enable-diskless
--enable-rtl8139 (and --enable-preset-menu=a_empty_preset in order to
manually config net).  PXE loaded the pxegrub smoothly, and I got GRUB
prompt and could do dhcp or ifconfig, so far so good.  When I set kernel
via (nd)... I got the error "28 : Selected item cannot fit into memory"
after some data downloaded.  Looked at mem it said "543 lower/56256K
upper memory", so it seems too little lower memory.  Having a quick look
in the source, I saw that there is a test "if (mbi.mem_lower >= 608
&& setup_sects < 60)" in "load_image", if not fulfilled it complains
ERR_WONT_FIT.

So my first question is what the magic number 608 means (I have no
experience of real mode). Second, might someone have some idea how to
solve such problem?

Regards,

#\Rui

PS.: I'm not on list yet, so please CC me if possible.