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  • Re: Re: Debian Installation on Ultra 30 (was Re: Updated Debian Ports i

    From Hermann.Lauer@uni-heidelberg.de@21:1/5 to Stan Johnson on Mon Sep 27 18:00:01 2021
    Hello Stan,

    On Mon, Sep 27, 2021 at 08:33:54AM -0600, Stan Johnson wrote:
    Having the above partitioning scheme seems to work ok with GRUB; the
    reason I asked about the "Whole disk" partition is that some
    partitioning tools (specifically fdisk, as I recall), refuse to create additional partitions once "Whole disk" has claimed all of the sectors. 

    Oh ok, couldn't remember how that was - our Sparks are in Storage since a
    few years now.

    In addition, there is an oddity (I think with parted, but I don't recall
    now) where the "Whole disk" partition needed to exist, otherwise the partitioner only recognized 1 GB. Perhaps this is related to parted complaining during installation that the number of cylinders on the disk exceeded the maximum of 65536 cylinders? Maybe parted is reading the
    disk geometry from the third partition on the disk regardless of what's there?

    No idea.

    So I ended up using this partitioning scheme; note that parted complains
    (but fdisk does not):

    # parted /dev/sda
    GNU Parted 3.4
    Using /dev/sda
    Welcome to GNU Parted! Type 'help' to view a list of commands.
    (parted) print                                                           
    Warning: The disk CHS geometry (562253,255,2) reported by the operating system does not match the geometry stored on the disk label
    (17849,255,63).
    Ignore/Cancel? C                                                         
    Model: SEAGATE ST3146807LC (scsi)
    Disk /dev/sda: 147GB
    Sector size (logical/physical): 512B/512B
    Partition Table: unknown
    Disk Flags:
    (parted) quit

    Looks to me that parted did not recognize sun disklabel format.

    # fdisk -l /dev/sda
    Disk /dev/sda: 136.73 GiB, 146815737856 bytes, 286749488 sectors
    Disk model: ST3146807LC    
    Geometry: 255 heads, 63 sectors/track, 17849 cylinders
    Units: sectors of 1 * 512 = 512 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    Disklabel type: sun

    Device        Start       End   Sectors   Size Id Type         Flags
    /dev/sda1         0   1048575   1048576   512M  1 Boot        
    /dev/sda2   1060290  17837505  16777216     8G 83 Linux native /dev/sda3  17848215  34625430  16777216     8G 83 Linux native /dev/sda4  34636140  68190571  33554432    16G 83 Linux native /dev/sda5  68195925  70293076   2097152     1G 82 Linux swap      u
    /dev/sda6  70300440 286744184 216443745 103.2G 83 Linux native

    The speciality of sun disklabel format is that sda1 contains the boot block (block 0) of the HD. I somehow misused that in the past to mirror
    the boot block in raid1 configurations of sda1. YMMV.

    It appears that SILO and GRUB do something similar -- they appear to be installed in the 1024-byte "boot block" of an ext2 filesystem; for more information, see this link for ext2 filesystem structure:

    http://www.science.smith.edu/~nhowe/teaching/csc262/oldlabs/ext2.html

    Yep, the filesystem needs to leave space for that boot block on (old)
    sparc machines on sda1 starting at sector 0. I wonder if there is an historic explanation for that somehow wicked setup on spark machines:
    Originally booting from a tape?

    Greetings
    Hermann

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