[syslinux] memdisk + grub2 consumes lot of memory

Miller, Shao shao.miller at yrdsb.edu.on.ca
Thu Dec 30 05:10:17 PST 2010

Good day again Keshav,

Does GRUB2 allow you to dump the memory map from its CLI _before_
booting tianocore (or whatever it's called)?  For example, if you can
look at the memory map _before_ booting MEMDISK and it doesn't look any
good, then MEMDISK shouldn't be responsible.  What might be nice to try
is loading MEMDISK and the initrd, but dumping the memory map before
booting it.

It's a boot-loader's responsibility (such as GRUB2 or Syslinux) where a
kernel (such as MEMDISK) and an initial RAM disk (such as your
Tianoxxx.img) are put in memory.

If MEMDISK then goes on to shuffle things around (such as gunzipping a
gzipped initrd), then it's possible that it might make different choices
about where to put the decompressed image based on whatever memory was
left by the boot-loader.

It's also possible that the MEMDISK "payload" containing its BIOS
INTerrupt hooks might be put somewhere different under GRUB2 than under
Syslinux, again, due to whatever memory map it was given by the

Another possibly interesting experiment would be to boot GRUB2 ->
MEMDISK + Syslinux floppy image.  On that floppy image, you could
include Syslinux' MEMDUMP.COM and find out what it reports.  Or

- Shao Miller

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