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grml to use MirOS manifold-boot CD technology

2009-05-26 by tg@
Tags: grml

grml GNU/Linux, our recently-partner project from Austria (not Australia), will gain ISO images bootable by dd(1)ing to a USB stick (or CF/SD card, hard disc, ...) via the MirOS manifold-boot technology, in use since 10/2007 and developed for the self-installing boot blocks. With only a couple of ifdefs, the MirOS BSD/i386 was made into a which runs fine on GNU/Linux (with mksh, of course!) and produces a first stage boot sector capable of loading a GNU GRUB2 core.img image the same as boot(8/i386) has been able to for a while. (GNU GRUB-legacy stage2 images cannot be loaded that way because bootxx is limited to 65280 bytes of second stage loader – mostly because the bootloader itself is, too, and this enabled me to squeeze out a few more bytes there.)

To say it with Mika Prokop himself:

23:22⎜«mikap:#grml» mirabilos: und dein bootloader ist geil :)
23:29⎜«mikap:#grml» und ich finds saugeil dass ich ein bsd zum booten mit
     ⎜  grml hab, das muss ich dann gleich mal auf usb-stick installieren

<mika:#grml> mirabilos: because: per default i still want to use isolinux
   (unless grub2 is working better, and: i'm missing the f2, f3,... splashes
   from isolunux)
<mirabilos:#grml> yep, nimm isolinux
<mirabilos:#grml> mkisofs -b hat damit gar nix zu tun
<mirabilos:#grml> das ISO bootet grub, wenns von USB gebootet wird, isolinux,
   wenns von CD gebootet wird
<mika:#grml> mirabilos: and the *same* ISO boots isolinux by default then but
   can be 'dd if=grml.iso of=/dev/sdb'-ed?!
<mirabilos:#grml> yep
<mirabilos:#grml> MirBSD doing that for a couple of years
<mika:#grml> mirabilos: awesome, i still don't get it but this sounds awfull
<mirabilos:#grml> mika: ours can even be booted on i386 via both methods *and*
   on a sparc
<mika:#grml> mirabilos: WTF?
<mirabilos:#grml> yep
<mirabilos:#grml> before MirGRML was added, our live CDs were already DuaLive?
<mika:#grml> awesome
<mirabilos:#grml> i386 boot (from cd, hdd, usb, compactflash, sd) into either
   live or install mode + sparc boot (voa OpenBOOT) into install mode
<mika:#grml> mirabilos: pfuh *verbeuge_again* :)

Ich glaube, Mika mag meinen Bootloader ;)

For simplicity, getextent_cd9660(1) will also be added to the grml-live ISO build process, as its output is easier to parse than J�rg's isoinfo. (I definitively should add subdir support there, just haven't gotten around to do it yet...) It uses a UCB and a TNF header file and otherwise available under the MirOS Licence (of course), as are the bootblocks.

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