OT: Little Disk Storage Mystery

Discussion in 'Asus' started by Puddin' Man, May 4, 2011.

  1. Puddin' Man

    Puddin' Man Guest

    Some folks like a little mystery. Some folks don't. The latter might wanna hit
    the delete key about now. Apologies for length, wrap(s), etc.

    Early in 2010 I started shopping for components for a new build. By May I had
    assembled a little desktop system around an Intel i5-650 cpu, Asus H55 mobo, a
    couple of Samsung 500gb HD's, etc. I installed Win7-64 Home Premium OEM to
    find that it created an extra 100mb partition on my disk for BCD/bitlocker etc
    (which I'd never use). I jumped thru some hoops involving Win7 "repair" to
    consolidate Win7 into the usual single partition. As I recall, it looked OK.

    By August I'd determined that I didn't wish to run Win7 on a daily basis, so I
    licensed and installed XP Pro in a dual boot config. I've been running XP
    daily ever since.

    Last fall Partition Wizard (bootable) reported there was an unallocated 7.84
    mb logical partition occupying sectors 0-16064. GParted confirmed it. Neither
    7 nor XP reports the existence of this space.

    Using the old c-h-s (cylinders-heads-sectors) referencing, the 16065 sectors
    constitute the first cylinder on the HD. My Speedfan SMART report indicates
    no HD problem.

    I have no idea where the 7.84 mb segment came from. Because Win7 does numerous
    unpredictable things (i.e. the 100 mb partition), I posted a query on
    Sevenforums:

    Unallocated 7.84 mb space materializes (from Outer Space?)
    http://www.sevenforums.com/general-...d-7-84-mb-space-materializes-outer-space.html

    As far as I can tell, no response from that thread explained the little
    mystery. Most folks suggested merging/resizing the 7.84 mb into the Win7 partition and
    forgetting the issue.

    Partition Wizard (bootable) showed some funny preview numbers and failed to
    merge it. When I tried to define the 7.84 mb as a new partition, PW
    crashed and burned, scaring the hull outa po' me. Parted Magic confirmed the
    "existence" of the mystery 7.84 mb.

    So I post here. It might be fairly simple to explain for Paul and/or some
    others, but I haven't figured it out.

    Any ideas? I just need to know what caused the mystery if I'm to be in full
    control of my system.

    Thx,
    P

    The relevant part of a Partition Wizard Export Config follows:

    Windows Major Version: 5
    Windows Minor Version: 1
    Build Number: 2600
    Windows Server OS: No
    64-bit Windows: No

    Disk 1, Total Sectors: 976773168, Name: SAMSUNG HD502HJ, GUID Partition Table: NO, Dynamic
    Disk: NO, CHS:60801/255/63

    letter: * PartID: 0 Start: 0 End: 16064 Size: 16065 FsId: 0 Label:
    ClusterSize: 1 FreeSectors: 16065 Primary: 0 Bootable: 0 BootVolume: 0
    SystemVolume: 0
    letter: C PartID: 7 Start: 16065 End: 163766609 Size: 163750545 FsId: 7 Label:
    SS1_P1_W7 ClusterSize: 8 FreeSectors: 120846008 Primary: 1 Bootable: 1 BootVolume: 1
    SystemVolume: 0
    letter: D PartID: 7 Start: 163766610 End: 331308494 Size: 167541885 FsId: 7 Label:
    SS1_P2_XP ClusterSize: 8 FreeSectors: 126060256 Primary: 1 Bootable: 0 BootVolume: 0
    SystemVolume: 1
    letter: E PartID: 7 Start: 331308495 End: 500601464 Size: 169292970 FsId: 7 Label:
    SS1_P3_Data ClusterSize: 8 FreeSectors: 163132776 Primary: 1 Bootable: 0 BootVolume: 0
    SystemVolume: 0
    letter: * PartID: 0 Start: 500601465 End: 928553183 Size: 427951719 FsId: 0 Label:
    ClusterSize: 1 FreeSectors: 427951719 Primary: 0 Bootable: 0 BootVolume: 0
    SystemVolume: 0
    letter: G PartID: 7 Start: 928553184 End: 976773104 Size: 48219921 FsId: 7 Label:
    SS1_P4_WDP2_W2K_PRD ClusterSize: 8 FreeSectors: 10975792 Primary: 1 Bootable: 0
    BootVolume: 0 SystemVolume: 0


    ***********MBR for SAMSUNG HD502HJ*************
    33 C0 8E D0 BC 00 7C 8E C0 8E D8 BE 00 7C BF 00
    06 B9 00 02 FC F3 A4 50 68 1C 06 CB FB B9 04 00
    BD BE 07 80 7E 00 00 7C 0B 0F 85 0E 01 83 C5 10
    E2 F1 CD 18 88 56 00 55 C6 46 11 05 C6 46 10 00
    B4 41 BB AA 55 CD 13 5D 72 0F 81 FB 55 AA 75 09
    F7 C1 01 00 74 03 FE 46 10 66 60 80 7E 10 00 74
    26 66 68 00 00 00 00 66 FF 76 08 68 00 00 68 00
    7C 68 01 00 68 10 00 B4 42 8A 56 00 8B F4 CD 13
    9F 83 C4 10 9E EB 14 B8 01 02 BB 00 7C 8A 56 00
    8A 76 01 8A 4E 02 8A 6E 03 CD 13 66 61 73 1C FE
    4E 11 75 0C 80 7E 00 80 0F 84 8A 00 B2 80 EB 84
    55 32 E4 8A 56 00 CD 13 5D EB 9E 81 3E FE 7D 55
    AA 75 6E FF 76 00 E8 8D 00 75 17 FA B0 D1 E6 64
    E8 83 00 B0 DF E6 60 E8 7C 00 B0 FF E6 64 E8 75
    00 FB B8 00 BB CD 1A 66 23 C0 75 3B 66 81 FB 54
    43 50 41 75 32 81 F9 02 01 72 2C 66 68 07 BB 00
    00 66 68 00 02 00 00 66 68 08 00 00 00 66 53 66
    53 66 55 66 68 00 00 00 00 66 68 00 7C 00 00 66
    61 68 00 00 07 CD 1A 5A 32 F6 EA 00 7C 00 00 CD
    18 A0 B7 07 EB 08 A0 B6 07 EB 03 A0 B5 07 32 E4
    05 00 07 8B F0 AC 3C 00 74 09 BB 07 00 B4 0E CD
    10 EB F2 F4 EB FD 2B C9 E4 64 EB 00 24 02 E0 F8
    24 02 C3 49 6E 76 61 6C 69 64 20 70 61 72 74 69
    74 69 6F 6E 20 74 61 62 6C 65 00 45 72 72 6F 72
    20 6C 6F 61 64 69 6E 67 20 6F 70 65 72 61 74 69
    6E 67 20 73 79 73 74 65 6D 00 4D 69 73 73 69 6E
    67 20 6F 70 65 72 61 74 69 6E 67 20 73 79 73 74
    65 6D 00 00 00 63 7B 9A 85 A3 85 A3 00 00 80 00
    01 01 07 FE FF FF C1 3E 00 00 91 A2 C2 09 00 FE
    FF FF 07 FE FF FF 52 E1 C2 09 7D 7C FC 09 00 FE
    FF FF 07 FE FF FF CF 5D BF 13 AA 34 17 0A 00 FE
    FF FF 07 FE FF FF E0 98 58 37 11 C7 DF 02 55 AA

    ***********DBR of Partition 1, disk SAMSUNG HD502HJ*************
    33 C0 8E D0 BC 00 7C 8E C0 8E D8 BE 00 7C BF 00
    06 B9 00 02 FC F3 A4 50 68 1C 06 CB FB B9 04 00
    BD BE 07 80 7E 00 00 7C 0B 0F 85 0E 01 83 C5 10
    E2 F1 CD 18 88 56 00 55 C6 46 11 05 C6 46 10 00
    B4 41 BB AA 55 CD 13 5D 72 0F 81 FB 55 AA 75 09
    F7 C1 01 00 74 03 FE 46 10 66 60 80 7E 10 00 74
    26 66 68 00 00 00 00 66 FF 76 08 68 00 00 68 00
    7C 68 01 00 68 10 00 B4 42 8A 56 00 8B F4 CD 13
    9F 83 C4 10 9E EB 14 B8 01 02 BB 00 7C 8A 56 00
    8A 76 01 8A 4E 02 8A 6E 03 CD 13 66 61 73 1C FE
    4E 11 75 0C 80 7E 00 80 0F 84 8A 00 B2 80 EB 84
    55 32 E4 8A 56 00 CD 13 5D EB 9E 81 3E FE 7D 55
    AA 75 6E FF 76 00 E8 8D 00 75 17 FA B0 D1 E6 64
    E8 83 00 B0 DF E6 60 E8 7C 00 B0 FF E6 64 E8 75
    00 FB B8 00 BB CD 1A 66 23 C0 75 3B 66 81 FB 54
    43 50 41 75 32 81 F9 02 01 72 2C 66 68 07 BB 00
    00 66 68 00 02 00 00 66 68 08 00 00 00 66 53 66
    53 66 55 66 68 00 00 00 00 66 68 00 7C 00 00 66
    61 68 00 00 07 CD 1A 5A 32 F6 EA 00 7C 00 00 CD
    18 A0 B7 07 EB 08 A0 B6 07 EB 03 A0 B5 07 32 E4
    05 00 07 8B F0 AC 3C 00 74 09 BB 07 00 B4 0E CD
    10 EB F2 F4 EB FD 2B C9 E4 64 EB 00 24 02 E0 F8
    24 02 C3 49 6E 76 61 6C 69 64 20 70 61 72 74 69
    74 69 6F 6E 20 74 61 62 6C 65 00 45 72 72 6F 72
    20 6C 6F 61 64 69 6E 67 20 6F 70 65 72 61 74 69
    6E 67 20 73 79 73 74 65 6D 00 4D 69 73 73 69 6E
    67 20 6F 70 65 72 61 74 69 6E 67 20 73 79 73 74
    65 6D 00 00 00 63 7B 9A 85 A3 85 A3 00 00 80 00
    01 01 07 FE FF FF C1 3E 00 00 91 A2 C2 09 00 FE
    FF FF 07 FE FF FF 52 E1 C2 09 7D 7C FC 09 00 FE
    FF FF 07 FE FF FF CF 5D BF 13 AA 34 17 0A 00 FE
    FF FF 07 FE FF FF E0 98 58 37 11 C7 DF 02 55 AA

    "Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."
     
    Puddin' Man, May 4, 2011
    #1
    1. Advertisements

  2. Puddin' Man

    Rob Guest

    It's likely just the 'leftover' sectors when clusters are allocated
    in whatever multiple was used in the format process.
     
    Rob, May 4, 2011
    #2
    1. Advertisements

  3. Puddin' Man

    andy Guest

    That unallocated disk space is there just in case you want to convert
    basic disks to dynamic disks.
     
    andy, May 4, 2011
    #3
  4. I'd say that your partitioning software starts each partition on a
    cylinder boundary and since cylinder 0 track 0 is used it skipped the
    rest of cylinder 0 and started the partition on cylinder 1.

    The last partition is a bit odd because it doesn't start or end on a
    cylinder boundary. Doesn't matter, just a bit odd.

    Cheers,
     
    Steven Saunderson, May 5, 2011
    #4
  5. Puddin' Man

    Puddin' Man Guest

    Cluster size was 8, per the PW report.

    16065 sectors "left over"??????

    P

    "Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."
     
    Puddin' Man, May 7, 2011
    #5
  6. Puddin' Man

    Puddin' Man Guest

    'Tis my understanding that XP install will sometimes allocate such
    space *after* the installed XP partition.

    The first 16065 sectors on the HD??????????

    P

    "Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."
     
    Puddin' Man, May 7, 2011
    #6
  7. Puddin' Man

    Puddin' Man Guest

    It was Win7 that originally partitioned my HD. 'Tis my understanding that Win7
    does *not* require alignment on cyl. boundaries.

    P

    "Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."
     
    Puddin' Man, May 7, 2011
    #7
  8. Quite true. Disks don't really have 255 heads or 63 sectors per track
    anyway. I was just commenting that the other partitions align to
    apparent cylinder boundaries and the last partition doesn't.

    The odd thing about the partitioning is that you have four primary
    partitions and yet haven't allocated all the disk space. Since a disk
    can only have four partition entries (one can be an extended partition)
    in the MBR I can't see how you can ever access the rest of the disk
    unless you relocate and extend the last partition.

    One good thing about aligning partitions to apparent cylinder boundaries
    is that disk checking software might expect this to be the case and
    report an error if any partitions aren't. Just a hangover from the
    olden days. Don't worry about the 7.84MiB unallocated space on cyl 0.
    The report is slightly erroneous anyway because you haven't really got
    16065 sectors unallocated. Track 0 is always reserved so at most you
    have 16002 sectors here.

    Cheers,
     
    Steven Saunderson, May 7, 2011
    #8
  9. Puddin' Man

    Puddin' Man Guest

    I was likely assuming that resizing existing partitions is more-or-less
    100% practical, so the unused space would get used wherever needed in
    the coming months/years.

    And the last partition is the system part. from a failed system,
    hence could go away altogether (if I can ever figure how to integrate
    all the data efficiently).
    Yes, I've seen that a time or 2.
    I'm not worried about the space ('tis trivial). Only worried about
    what caused it to be there.
    "Track 0 is always reserved". You can provide perhaps references to
    this rule?

    The mystery persists (at least for me). If you'd care to explain exactly
    when/how the 7.84mb appeared in sectors 0-16064 in the context of:

    1.) Win7 DVD installs to unformatted HD.
    2.) Same Win7 DVD ("repair") consolidates 2 part's into one.
    3.) XP CD installs to second partition.
    4+) Etc, etc.

    then I am all ears.

    Probably some silly detail I am somehow missing. :)

    Prost,
    P

    "Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."
     
    Puddin' Man, May 10, 2011
    #9
  10. Oops, I have to admit that I can't easily provide any references. I
    must have had such a document years ago but doubt that I still do. The
    first sector is the master boot record (MBR). To enable older PCs to
    access these new-fangled hard drives some providers put BIOS extension
    code in the following sectors and this code was loaded when the drive
    was first accessed. Some partitioning software puts recovery data (e.g.
    backup MBR) in the last three sectors of track 0. I don't know of a
    drive with less than 16 sectors per track and don't think there was ever
    an overlap of the disk access code and recovery info. So, I've always
    regarded track 0 as a reserved area and I wouldn't risk starting a
    partition there.
    I don't think you're missing any detail here. The Win7 partitioning
    program just wants to align partitions to (virtual) cylinder boundaries.
    The program I use will start a partition at cyl 0 track 1 and this works
    just fine. I'm not sure why your partitioning program didn't want to
    use the rest of cylinder 0 but if there is a good reason then your setup
    will work in installations where mine will crash and burn. This would
    surprise me because NT4 onwards uses LBA everywhere and cylinders and
    tracks don't exist in this world. Just for safety I leave the remainder
    of tracks containing an MBR or EPBRs alone in case any utility program
    assumes it can use these sectors.

    Cheers,
     
    Steven Saunderson, May 10, 2011
    #10
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.