[syslinux] isohybrid and ISO images whose size is not a multiple of 2048 bytes vs. VirtualBox

Martin Str|mberg ams at ludd.ltu.se
Mon May 18 10:54:07 PDT 2015


I just want to comment on this Oh nooo, virtualbox can boot because of
image not an even multiple of 2048 sector, so we must do some crazy
stuff.


To Tails creators (and anyone else that might be interested):
First I want to hear if anyone has failed to boot such non-even-
multiple-of-2048-sectors on real hardware?

Because the virtualbox I tried 2013 or 2014 (don't remember exactly
when) couldn't even boot an image of selfmade SLES 9.3 boot
cd. Meanwhile that image burned to a real CD does boot on real
hardware. I haven't bothered with virtualbox since.


To Thomas (and anyone else that might be interested):
That fdisk complains means nothing on current BIOSes and harddisks (and
SSDs). Current hardware does use LBA. That cylinder misalignment is
only for the obsolete CHS handling. Every partitioner on Linux seems
to have their own weird ideas how it should be and noone is the same
as any other.

However I don't know much about how CD booting works. So it's possible
that that still uses that old stuff. Again, do anyone has some
evidence that these non-even-multiple-of-2048-sectors doesn't work on
real hardware? It seems to me from Thomas mails that Debian has
(inadvertedly) tested this successfully.


-- 
MartinS


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