-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Thu, Apr 16, 2009 at 09:06:15PM -0400, Caroline Meeks wrote: >Ahh, this maybe where some of the confusing behavior we were seeing >comes from. Let me repeat what I think I understand so I can see if I >have it right. > >FAT is the same thing as FAT16 >FAT is only an option for USB sticks 2 GB or less. You can only format >a USB stick larger then 2 GB as FAT32. >Some computers will not boot from a FAT32 formatted stick but some >will. > >Thus if you put SoaS onto a 4 GB USB it will fail on some computers and >not others. > >A partition allows you to have one part of the USB formatted >differently then another part. > >Thus a work around if you want to use a USB stick larger then 2GB would >be to create a smaller partition for the boot area and format that as >FAT. > >Let me know what I have right and wrong!
You got it right. But there are more works in that can: FAT is _often_ FAT16. In addition to FAT16 and FAT32 there is also FAT12, which some BIOSed might expect in USB-FDD mode. Also, some BIOSes do not support booting from a USB stick containing more than a single partition...: The various bugs in BIOS implementations apart, there are 3 kinds of boot methods for USB storage devices: USB-FDD, USB-HDD and USB-ZIP. USB-FDD expects no MBR (Master Boot Record), but instead one single unpartitioned whole - like a very large floppy disk. USB-FDD expects an MBR with standard DOS partition table - like a harddisk. USB-ZIP expects an MBR with specific DOS partition table - like a ZIP drive. makebootfat includes a special "mbrfat" combination that makes the device look like an unpartitioned single whole to BIOSes expecting USB-FDD, while presenting an MBR with a DOS partition table for BIOS-HDD use (and possibly BIOS-ZIP too). I strongly recommend to read the manpage for makebootfat. I don't know any tools to reverse-engineer boot sectors, which means it is not enough to say "yes, it works with makebootfat" - you need to document *what* works for *which* machine setup to use *what* USB access method. If you want to approach this systematically, to gain knowledge on what hardware supports which combinations of boot methods and tricks, then I strongly suggest that you try use makebootfat to prepare the USB sticks, or closely read documentation and/or code of other chosen tools to understand what exactly they do in comparison. Kind regards, - Jonas - -- * Jonas Smedegaard - idealist og Internet-arkitekt * Tlf.: +45 40843136 Website: http://dr.jones.dk/ [x] quote me freely [ ] ask before reusing [ ] keep private -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEARECAAYFAknoNn0ACgkQn7DbMsAkQLiifgCfZLRgzR6DWrxOpEMBODwpQOa3 tlkAn370vm1hW+efS+0rQtvC7THSglkh =Rm6F -----END PGP SIGNATURE----- _______________________________________________ IAEP -- It's An Education Project (not a laptop project!) [email protected] http://lists.sugarlabs.org/listinfo/iaep
