SDL on usb stick

[Lennart Sorensen]

On Wed, Apr 04, 2007 at 07:41:21PM -0400, D. Hugh Redelmeier wrote:
> I think that there is (after googling a bit).  But it does not say
> what the contents of the medium should look like:
>   http://www.usb.org/developers/devclass_docs/usb_msc_boot_1.0.pdf
> 
> I always assumed that you organized a flash memory like a hard disk
> partition OR like a partition.  The first sector would be a Boot
> Record and would contain a 512-byte boot block.  I'm more confused now
> that I've looked it up.

Well sometimes it is treated like a big floppy, and other times like a
hard disk.  So sometimes you get partitions and sometimes you don't.
Some bios's have settings for USB Zip, USB Floppy, or USH HD for boot,
which affects which setup it will expect and boot from.

> Of course bootable CD's don't look like that.  They have a virtual
> floppy image that the BIOS can boot from and make available to the
> boot code etc. through INT 13.  As a virtual floppy, it is
> allowed to be 2.88M, even though few real floppies were that size.
> (Apparently it could also emulate a hard drive).
>   http://en.wikipedia.org/wiki/El_Torito_(CD-ROM_standard)

Actually floppy emulation isn't used very often anymore.  Now most
things use el torito no emulation mode, where the whole iso filesystem
can be read through the bios interface.  This is what isolinux uses, as
well as all windows installers for NT based windows versions.  Most x86
linux distributions use isolinux for booting as far as I know.  The
floppy emulation is just so restrictive in space and very annoying to
generate so hardly anyone uses it anymore.

> Of course the PC world had to re-invent bootable CDs (1995).  Sun had
> differently bootable CDs quite a bit earlier.

Well many unix systems could boot from CD, but they required that the CD
drive support 512byte sectors, which some scsi cdrom drives did, but
most do not.  Most do only 2048 byte sectors.

--
Len Sorensen
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