booting from FRAGMENTED ISO

Benny
2010-02-26
2013-02-08
  • Benny
    Benny
    2010-02-26

    you know I am mad to boot from ISO, so I installed the new 2.8 on my 320GB Lacie USB drive  and SET LANGUAGE TO ITALIAN …

    all my ElTorito partitions were read on Lacie, but ALSO the puppy.iso pelican.iso on the fixed disk /dev/hda1 on a FAT partition.

    Problem: Gujin gave a message of FRAGMENTED ISO files. GRRRRRRR!!!!
    Solution: I downloaded from www.sysinternals.com the contig.exe utility and I defragmented the iso files
    c:\>contig *.iso

    REBOOT  and GO

    ALTERNATIVE solution by Etienne:
    the first big file in FAT32 will be put in all the small
    allocation holes before reaching a contiguous area.
    It usually helps to defragment the FAT filesystem, or to copy the file
    twice: the first one will be a lot more fragmented than the second
    copy - you can then remove the first copy. That is a usual problem
    with FAT.

    ciao
    benny59

     
  • The maximum number of fragments of an iso file to boot as El-Torito is 64, it could be increased a bit - but a DVD image can potentially have thousands of fragments, and that will not be easy to manage: each fragment takes 12 bytes in the resident program to simulate the BIOS disk, resident program left active in memory after Gujin exits. This resident should be kept extremely small to not bother other applications loaded after Gujin exits.

     
  • Benny
    Benny
    2010-02-27

    -_->>>>WELL DONE<<<<-_-

    This answer is written from Lucid Lynx alpha 3.ISO downloaded to disk C:\ or /dev/hda1 and booted with Gujin 2.8

    the iso file has 44 fragments

    Next Challenge: get the same results using  a USB stick

     
  • Benny
    Benny
    2010-02-27

    Bad News:

    Luxyd Lynks DID initially boot from ISO but then it found the OTHER El-Torito partition on my Lacie and continued booting from that partition so the success is only theorical. tricky.

    I realized that by repeating the same operation from an USB stick only loading gujin AND LucidLynx. After the initial phase the looping filesystem cannot be mounted (as usual)

    .piety.

     
  • What am I saying from the beginning?
    The only way to start an ISO image is if that distribution accept the bootfrom= parameter, and even then you can only use the second method of the release message to start the distribution; to use the third method (directly load the El-Torito), Gujin has to be the El-Torito file itself to recognise the INT13 signature describing which file is being emulated by the BIOS disk.
    I do not know if Luxyd Lynks accept the bootfrom= parameter.
    Note that you can use the "showmap" utility in standard-2.8.tar.gz to see the number of fragments.

     
  • Benny
    Benny
    2010-02-28

    I do not know if Luxyd Lynks accept the bootfrom= parameter.

    that infact was my excitement as it worked… but simpy LL found how to keep booting from /dev/sdb8 …

    keep making tests
    benny