FDISK -> LVM question - OS2

This is a discussion on FDISK -> LVM question - OS2 ; Hello, I'm planning to add LVM to a Warp4 FP15 system. I've done this already on another system (HPFS only and no boot manager): add drivers to config.sys, use DFSee to add LVM info to partitions, reboot, done. The system ...

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Thread: FDISK -> LVM question

  1. FDISK -> LVM question

    Hello,

    I'm planning to add LVM to a Warp4 FP15 system. I've done this already on another system (HPFS only and no boot
    manager): add drivers to config.sys, use DFSee to add LVM info to partitions, reboot, done.

    The system I want to upgrade now is bit more complex, it has the following partitions:

    Primary Boot-Manager
    Primary Windows 2000 (NTFS) "C:"
    Primary OS/2 Boot (HPFS) "C:"
    Extended OS/2 Data (HPFS) "D:"
    Extended OS/2 Data (HPFS) "E:"
    Extended Shared Data (FAT32) "F:"

    OS/2 sees the HPFS and FAT32 partitions C:, D:, E: and F:
    Windows sees the NTFS and the FAT32 partitions C: and F:

    Questions:
    * Will drive letters in Windows 2000 be affected by the LVM info? If for example the NTFS partition drive letter in OS/2 is
    changed to "G:", will Windows see it's boot drive as "G:" or will it remain as "C:"?
    * Will the drive letter setting in Windows 2000 influence OS/2? Currently, the HPFS partitions D: and E: do not have drive
    letters assigned in Win2000. Will the drives disappear in OS/2 when using LVM?

    Thanks and regards
    Stefan




  2. Re: FDISK -> LVM question

    > OS/2 sees the HPFS and FAT32 partitions C:, D:, E: and F:
    > Windows sees the NTFS and the FAT32 partitions C: and F:
    >
    > Questions:
    > * Will drive letters in Windows 2000 be affected by the LVM info? If for example the NTFS partition drive letter in OS/2 is
    > changed to "G:", will Windows see it's boot drive as "G:" or will it remain as "C:"?


    Drive letters in Win are usually not affected by the LVM ones.

    There is just one strange issue with HPFS partitions.
    Windows XP somehow picks up the HPFS partitions when you have assigned a drive
    letter to them via LVM and assigns them also a letter. They appear in WinXP
    then as non-formatted drives.
    You can easily correct this in the Windows drive manager (remove the drive letters)
    but before this you need to be careful. At least Windows XP has this habbit to
    ask you automatically to format a partition via a popup dialog once you try to
    access it. If you press OK (Return key), your data are gone. If you have the
    relevant drive letters removed, all is good.

    > * Will the drive letter setting in Windows 2000 influence OS/2? Currently, the HPFS partitions D: and E: do not have drive
    > letters assigned in Win2000. Will the drives disappear in OS/2 when using LVM?


    No. Windows and OS/2 can have different drive letters for the same partition.

    Some additional notes:
    Only add drive letters to partitions you really want to use and for that
    you have a file system driver for. So you don't need to assign a drive
    letter to the NTFS partitions.
    Also you should set the same drive letter to all OS/2 partitons via LVM
    as they were before. Otherwise your system might not be bootable anymore!


  3. Re: FDISK -> LVM question

    On Sun, 29 Jul 2007 14:39:27 +0200 (CDT), Stefan Pelz
    wrote:

    > * Will drive letters in Windows 2000 be affected by the LVM info? If for example the NTFS partition drive letter in OS/2 is
    > changed to "G:", will Windows see it's boot drive as "G:" or will it remain as "C:"?
    > * Will the drive letter setting in Windows 2000 influence OS/2? Currently, the HPFS partitions D: and E: do not have drive
    > letters assigned in Win2000. Will the drives disappear in OS/2 when using LVM?


    No. Windows knows nothing about OS/2s LVM info. and OS/2 knows nothing about
    Windows' driver letter naming.

  4. Re: FDISK -> LVM question

    On Sun, 29 Jul 2007 17:26:56 UTC, Paul Ratcliffe
    wrote:

    > On Sun, 29 Jul 2007 14:39:27 +0200 (CDT), Stefan Pelz
    > wrote:
    >
    > > * Will drive letters in Windows 2000 be affected by the LVM info? If for example the NTFS partition drive letter in OS/2 is
    > > changed to "G:", will Windows see it's boot drive as "G:" or will it remain as "C:"?
    > > * Will the drive letter setting in Windows 2000 influence OS/2? Currently, the HPFS partitions D: and E: do not have drive
    > > letters assigned in Win2000. Will the drives disappear in OS/2 when using LVM?

    >
    > No. Windows knows nothing about OS/2s LVM info. and OS/2 knows nothing about
    > Windows' driver letter naming.


    My previous box had OS/2, XP, Linux, and AirBoot. If I used Drive
    Manager to change (remove) any drive letters from HPFS partitions found
    by XP, AirBoot would complain that the MBR had become corrupted and
    insist on being repaired. Then XP wouldn't boot because its internal
    partition enumerationing scheme would come up with different
    information, making it nessary to experiment with the partition numbers
    in boot.ini until it would boot (make several menu selections and try
    each until XP booted). Using DFSee to restore the previous MBR
    information would always rectifiy the situation. XP does something
    somewhere in the MBR tables, probably in a slightly different location
    than LVM because OS/2's drive letters and booting were never affected.

    My temporary work-around was to give the partitions easily recognizable
    volume lables because for some reason XP wouldn't let me assign the
    same letter it has under OS/2 (F:, which was one of three CD drives
    under XP), and then /never/ allow XP to format any partition. To get
    away from these MBR issues, when I set up my new box, I swtiched to
    IBM's boot manager, but I haven't yet had the time to experiment with
    drive letter hiding under XP (use it only once in a great while).

    Pete

    --


  5. Re: FDISK -> LVM question

    On Sun, 29 Jul 2007 19:30:43 +0200, Heiko Nitzsche wrote:

    >There is just one strange issue with HPFS partitions.
    >Windows XP somehow picks up the HPFS partitions when you have assigned a drive
    >letter to them via LVM and assigns them also a letter. They appear in WinXP
    >then as non-formatted drives.
    >You can easily correct this in the Windows drive manager (remove the drive letters)
    >but before this you need to be careful. At least Windows XP has this habbit to
    >ask you automatically to format a partition via a popup dialog once you try to
    >access it. If you press OK (Return key), your data are gone. If you have the
    >relevant drive letters removed, all is good.


    Already removed the drive letters in Win2000. Win2000 also wants to format the partitions ...

    Kind Regards
    Stefan



  6. Re: FDISK -> LVM question

    On Sun, 29 Jul 2007 17:26:56 GMT, Paul Ratcliffe wrote:

    >No. Windows knows nothing about OS/2s LVM info. and OS/2 knows nothing about
    >Windows' driver letter naming.


    Ok, I'll give it a try then.

    Where do OS/2 and Win store the information? Unused sectors? Registry?

    Kind Regards
    Stefan



  7. Re: FDISK -> LVM question

    On Mon, 13 Aug 2007 08:42:32 UTC, "Stefan Pelz" wrote:
    Hi Stefan,

    > >No. Windows knows nothing about OS/2s LVM info. and OS/2 knows nothing about
    > >Windows' driver letter naming.

    >
    > Ok, I'll give it a try then.
    >
    > Where do OS/2


    OS/2 (with LVM) stores the information in previously unused sectors.
    To be more precise:

    1) There is ONE LVM 'Drive Letter Assignment Table' sector (DLAT)
    for all the primaries on a disk, located at the last sector of the MBR track.
    This is usually at sector 0x3f (63)

    2) There is a DLAT sector for every logical partition/volume,
    located in the last sector of the track that holds the EBR for it too.

    3) There is a whole extra area of sectors at the END of the special
    LVM volumes, of type 0x35, that are typically used with JFS.

    You can see all of that (and more :-) using DFSee:

    Display ->
    LVM info for partition(s)


    >and Win store the information? Unused sectors? Registry?


    Windows has various ways of storing driveletter info, most
    is located in the registry ('disk' key for example), so it is NOT
    available to other operating systems, unlike LVM-info which
    is outside the scope of any filesystem.

    However, the exact format and functionality of that has changed
    quite a few times since the original Windows-NT, and is poorly
    documented.

    Regards, JvW

    --
    Jan van Wijk; Author of DFSee: http://www.dfsee.com

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