Contents of the extra/ directory
 ================================
 
 Data and configuration files to support generation of sos on non-x86
 and/or grub-less hosts:
  - dot.mkvars: file to copy as .mkvars in the root directory to
    compile on a non-x86 host, and to generate the grub floppy image on
    a grub-less host
  - grub.img.gz: compressed image of a Grub floppy (without any
    kernel). Used by dot.mkvars.
  - mtoolsrc: file needed by .mkvars to compile a the floppy image
 
 Support of a sos-specific boot sector:
  - Makefile: rules to compile sos_bsect.img, the floppy image with the
    boot sector and the Sos
  - bootsect.S: x86 Sos boot sector (GNU as). Depends on sos_bsect.lds
  - sos_bsect.lds: ld script to bind the boot sector with the remaining
    of the kernel
 
 Misc:
  - qemu-port-e9.diff: patch over qemu to support the bochs "port 0xe9 hack"
 
 
 What you can do with these files
 ================================
 
 
 *** Compile SOS from another architecture:
 ------------------------------------------
  - compile a cross-compiler for the i586-gnu target. This involves
    compiling the binutils and gcc. Here are example configuration
    options for them:
    binutils (replace sparc-cun-solaris with your arch):
      ../binutils-2.13/configure --prefix=/udd/ddecotig/temp_dd/xgcc/host-sparc-solaris7/stow/binutils-2.11 --host=sparc-sun-solaris2.7 i586-gnu
      make && make install
    gcc (ditto):
      CFLAGS="-O2 -Dinhibit_libc" ../gcc-3.2/configure --target=i586-gnu --prefix=/udd/ddecotig/temp_dd/xgcc/host-sparc-solaris7/stow/gcc-3.2 --with-as=/udd/ddecotig/temp_dd/xgcc/host-sparc-solaris7/bin/as --with-ld=/udd/ddecotig/temp_dd/xgcc/host-sparc-solaris7/bin/ld --with-gnu-as --with-gnu-ld --enable-languages=c --disable-shared --disable-multilib --disable-nls --enable-threads=single
      make && make install
  - compile the mtools
  - copy dot.mkvars to the root directory of SOS, as ".mkvars"
  - customize the CC/LD/... variables to suit your cross-compiler
    installatioon
  - now you may run make from the SOS root directory, it should
    generate the Grub boot floppy image. The following warning is
    normal:
      .mkvars:16: attention : écrasement des commandes pour la cible « grub-sos.img »
      Makefile:92: attention : anciennes commandes ignorées pour la cible « grub-sos.img »
 
 
 *** To compile SOS from an x86 where grub is not or incorrectly installed:
 --------------------------------------------------------------------------
  - copy dot.mkvars to the root directory of SOS, as ".mkvars"
  - customize the CC/LD/... variables to suit your cross-compiler
    installatioon
  - now you may run make from the SOS root directory, it should
    generate the Grub boot floppy image. The following warning is
    normal:
      .mkvars:16: attention : écrasement des commandes pour la cible « grub-sos.img »
      Makefile:92: attention : anciennes commandes ignorées pour la cible « grub-sos.img »
 
 
 *** To compile SOS with its own bootloader:
 -------------------------------------------
  - for cross-architecture compilation: see above
  - cd to this extra/ directory
  - run 'make'
  - the floppy image is: sos_bsect.img for use with bochs or on a real
    floppy disk
    to use the image under qemu: use sos_qemu.img
 
  NOTE : From article 2 onward, be warned that using this bootsect
         might lead to system crashes. This would be because the
         solution we use to retrieve the RAM size might not work
         properly on some systems (BIOS buggy or more than 1G RAM). THE
         best way to boot SOS is always to use Grub.
 
 
 --
 David Decotigny