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Partition map is wrong... - Linux / Unix Administration

I have a 30GB iPod, that doesn't appear to have all its space allocated properly... from the shell: pdisk /dev/disk1 -dump shows: Partition map (with 512 byte blocks) on '/dev/disk1' #: type name length base ( size ) 1: Apple_partition_map partition map 62 1 2: Apple_MDFW firmware 131072 63 ( 64.0M) 3: Apple_HFS disk 34082496 131136 ( 16.3G) Device block size=512, Number of Blocks=34213643 (16.3G) DeviceType=0x0, DeviceId=0x0 Notice the Apple_HFS disk? It says 16.3G Notice the base? Why is that so high? Really it should say something like: (From another iPod) /dev/disk2 map block size=512 #: type name length base ...

  1. #1

    Default Partition map is wrong...

    I have a 30GB iPod, that doesn't appear to have all its space allocated
    properly...
    from the shell:

    pdisk /dev/disk1 -dump

    shows:

    Partition map (with 512 byte blocks) on '/dev/disk1'
    #: type name length base ( size )
    1: Apple_partition_map partition map 62 1
    2: Apple_MDFW firmware 131072 63 ( 64.0M)
    3: Apple_HFS disk 34082496 131136 ( 16.3G)

    Device block size=512, Number of Blocks=34213643 (16.3G)
    DeviceType=0x0, DeviceId=0x0

    Notice the Apple_HFS disk? It says 16.3G
    Notice the base? Why is that so high?

    Really it should say something like: (From another iPod)

    /dev/disk2 map block size=512
    #: type name length base ( size )
    1: Apple_partition_map partition map 62 1
    2: Apple_MDFW firmware 65536 63 ( 32.0M)
    3: Apple_HFS disk 78060448 65599 ( 37.2G)

    Like 37.2 Gig more or less...

    I would like to reinitialize the drive such that the partition table is
    correct..
    I believe i need to delete the partition map and recreate it ...
    Any help?

    I

    KraftDiner Guest

  2. #2

    Default Re: Partition map is wrong...

    Also if I try to edit the map I get the message
    The map is not writable...
    Is this permissions on the device?
    chmod w+a ?
    by the way there are two devices...
    /dev/rdisk1 and /dev/disk1
    Physical? Logical?

    KraftDiner Guest

  3. #3

    Default Re: Partition map is wrong...

    In article <googlegroups.com>,
    KraftDiner <com> wrote:
     

    It would appear that there is a free-space area of 11GB between your
    firmware partition and your HFS partition.

    Why this free space area is not showing up in your pdisk printout, I
    don't know.

     

    That would not do it. The partition map is not re-created when you
    initialize.

     

    That would work if you _partition_ the iPod.
    (as one big partition)

    Running pdisk afterwards should show up the missing space.

    Mark-


    KraftDiner entire post - 
    Mark Guest

  4. #4

    Default Re: Partition map is wrong...

    In article <googlegroups.com>,
    KraftDiner <com> wrote:
     

    Definitely "Logical", because there is only one iPod device.

    I do not understand the difference between "rdisk1" and "disk1",
    although several people have tried to explain the difference to me.

    I just use rdisk1 all the time, so far that has worked for me.

    I am at a loss as to when it is appropriate to use just plain "disk1".

    Mark-



    Entire KraftDiner post - 
    Mark Guest

  5. #5

    Default Re: Partition map is wrong...

    On Thu, 22 Dec 2005 15:47:10 GMT, Mark Conrad <com> wrote:
     

    One's raw and describes the physical device, the other has a filesystem
    built on it and describes the filesystem. And now get back in the
    killfile, Mark/Gerald/Etc, you nym-shifting troll.

    Dave Guest

  6. #6

    Default Re: Partition map is wrong...

    In article <221220050735586049%com>,
    Mark Conrad <com> wrote:
     
    >
    > It would appear that there is a free-space area of 11GB between your
    > firmware partition and your HFS partition.[/ref]

    ??? 63 (base) + 131,072 (length) = 131,135. add "1" for the new base
    gives 131136 which matches the partition map.


    There might be some question about why the firmware partition is twice
    the size as that of the second iPod's drive, but that's another issue
    entirely. 
    >
    > That would not do it. The partition map is not re-created when you
    > initialize.
    >

    >
    > That would work if you _partition_ the iPod.
    > (as one big partition)
    >
    > Running pdisk afterwards should show up the missing space.
    >
    > Mark-[/ref]

    What kind of nonsense is that? [/ref]

    --
    Tom Stiller

    PGP fingerprint = 5108 DDB2 9761 EDE5 E7E3
    7BDA 71ED 6496 99C0 C7CF
    Tom Guest

  7. #7

    Default Re: Partition map is wrong...

    In article <221220050748291673%com>,
    Mark Conrad <com> wrote:
     
    >
    > Definitely "Logical", because there is only one iPod device.
    >
    > I do not understand the difference between "rdisk1" and "disk1",
    > although several people have tried to explain the difference to me.
    >
    > I just use rdisk1 all the time, so far that has worked for me.
    >
    > I am at a loss as to when it is appropriate to use just plain "disk1".[/ref]

    rdisk1 is a raw device interface. I/O to a raw device goes
    straight to and from the device, _AND_ _MUST_ start on a sector
    boundary, and the write size _MUST_ be in even multiples of the
    sector size.

    disk1 is a block device interface. I/O to a block device goes
    through system buffers. That is to say, a write is first
    transferred to from your application buffer to a system buffer.
    At some time in the future, the data you wrote will be flushed to
    disk (the update daemon), unless your program/utility calls
    sync(), or fsync(), or you issue the command sync.

    A block device read will first check the system buffers, and if
    the data is there, it will copy the data from the system buffers
    to your application buffer. If the data is not there, then the
    data will first be read into a system buffer, and then copied to
    your application buffer.

    The advantage of a block device is writes can be buffered up and
    then instead of a lots of small writes, a single larger write can
    be issued to the disk, especially if random I/O is being performed
    (of course if your raw writes are already large, this is not as
    much of a problem). And reads that re-read the same data
    frequently can get the data from the system buffers and avoid an
    I/O all together. This can provide a much faster interface to the
    disk as, there may actually be fewer physical I/Os actually
    happening.

    The disadvantage of a block device is that _IF YOU DO NOT_ need
    the caching, you are consuming system space with data, pushing
    other cached file data out of memory, and you are doing memory to
    memory copies using CPU and invalidating CPU hardware caches that
    could be better used for application data and instructions.
    Database applications like to avoid the system cache, as they
    maintain their own cache internal to the database application, and
    a 2nd cache in the system space is memory that they can not use,
    and the extra overhead of copying data between the database cache
    and the system buffers is wasted CPU time.

    A lot depends on what you are doing with the rdisk1 and whether or
    not its interface is appropriate for your use.

    Bob Harris
     [/ref]
    Bob Guest

  8. #8

    Default Re: Partition map is wrong...

    Ya I eventually figured out rdisk and disk.
    And the 'offset'.
    But I never quite figured out how come the drive insisted on being a
    16Gig Drive.
    My assumption was that the 3rd partition needed to be redone.. I did
    that and reloaded
    the os and the 3rd partition went back to 16Gig yet again... So I gave
    up...
    I left it at that thinking maybe there were bad tracks and that I had
    no way of editing
    the bad track table... Course I could be wrong and would love to here
    if that is a possibility.
    Long time ago I would have done a low level format on the drive.. but
    those days are gone...
    Now what does one do? S.M.A.R.T drives??? SMART Utilities?

    KraftDiner Guest

  9. #9

    Default Re: Partition map is wrong...

    On 22 Dec 2005 19:35:52 -0800, KraftDiner wrote:
     

    Stop treating your ipod as a piece of computer kit and start treating it
    like a piece of consumer electronics. If the sticker on the back says 30Gb
    and you only get 16Gb usable then tell the bloke in the shop and get a
    replacement.
    Adam
    Adam Guest

  10. #10

    Default Re: Partition map is wrong...

    Yes Sir Adam! :)
    Adam the iPod has been sent to Apple. As you demanded ;)
    However my questions are about hard drives and Unix administration of
    the
    and the tools. If I want to treat my iPod as the hard drive it is,
    then I will because
    that is what it is. If I want to load Linux on it I may.

    bobrien18@yahoo.com Guest

  11. #11

    Default Re: Partition map is wrong...

    On 23 Dec 2005 09:28:23 -0800, com <com> wrote: 

    What an odd way to thank someone who helped you with _your problem_.
     

    Of course. And if people here want to disregard your postings, due to
    your apparent attitude problem towards those helping you, they may.
    Maybe I'm reading you wrong, but it came across like you're getting
    snarky to the guy who helped you. That's a good way to have others not
    bother with your next problem.

    Dave Guest

  12. #12

    Default Re: Partition map is wrong...

    I think you overlooked the smilies.. ;)

    bobrien18@yahoo.com Guest

  13. #13

    Default Re: Partition map is wrong...

    I think you overlooked the smilies.. ;)

    bobrien18@yahoo.com Guest

  14. #14

    Default Re: Partition map is wrong...

    In article <verizon.net>,
    Bob Harris <Smith-Harris.us> wrote:
     

    Thanks for the detailed explanation.

    I do once-only large reads and writes, always starting and ending at
    512-byte sector boundaries, so I guess I will continue using rdisk0,
    rdisk1, etc.

    There certainly are subtle differences between the two.

    If I understand your post correctly, the differences _only_ affect
    the speed of the copy operation, and the CPU load, and whether-or-not
    the copying starts at a sector boundary or not.

    Mark-
    Mark Guest

  15. #15

    Default Re: Partition map is wrong...

    In article <dca.giganews.com>,
    Tom Stiller <net> wrote:
     

    Whoops, you are correct, the missing space is between the HFS partition
    and the end of his iPod disk.

    In any case, a simple re-partition of his iPod should fix the
    discrepancy.


    I do not own an iPod, but the OP seems to believe that the iPod acts
    like a regular disk drive. If so, it can be re-partitioned as one
    partition by Disk Utility, thereby effectively rebuilding the (possibly
    corrupted) partition map, and showing the correct size of his HFS
    partition when pdisk is run.


    Mark-
    Mark Guest

  16. #16

    Default Re: Partition map is wrong...

    In article <221220052339353512%com>,
    Mark Conrad <com> wrote:
     
    >
    > Whoops, you are correct, the missing space is between the HFS partition
    > and the end of his iPod disk.[/ref]

    I'd hardly worry about 11 sectors at the end of the disk. I would more
    suspect that he has a 15 GB iPod. 

    --
    Tom Stiller

    PGP fingerprint = 5108 DDB2 9761 EDE5 E7E3
    7BDA 71ED 6496 99C0 C7CF
    Tom Guest

  17. #17

    Default Re: Partition map is wrong...

    Do they actually make 16Gig iPod?

    bobrien18@yahoo.com Guest

  18. #18

    Default Re: Partition map is wrong...

    In article <dca.giganews.com>,
    Tom Stiller <net> wrote:
     
    >
    > I'd hardly worry about 11 sectors at the end of the disk. I would more
    > suspect that he has a 15 GB iPod.[/ref]

    Egad, Double Whoops - - -

    You are correct again, I missed the total count of sectors.

    Aren't Senility Wonderful.


    It certainly appears that he has a 15 GB iPod.



    Oh well, at least _I_ got something out of this thread, by learning
    even more about the differences between "disk0" and "rdisk0".

    Many thanks to Bob Harris, for all the time and effort he devoted to
    explaining that subject.

    Just goes to show, it pays to jump in and appear to be an .

    Gotta make a note to myself to continue doing that - - - namely jumping
    into a thread and offering my often inaccurate opinion/advice/wisdom.

    Mark-

    --
    "The 'Truth' is something that is most easily learned by
    approaching it in increasingly more accurate approximations."

    - - - Mark Conrad, 2005 AD - - -
    Mark Guest

  19. #19

    Default Re: Partition map is wrong...

    On 23 Dec 2005 19:50:58 -0800, com <com> wrote: 

    Nobody knows who or what you're talking to or about. Include some
    context and who said it, or your messages don't make any sense.
    google is great for many things. Usenet posting isn't one of them.
    Dave Guest

  20. #20

    Default Re: Partition map is wrong...

    In article <googlegroups.com>,
    com wrote:
     

    AFAIK, Apple never advertised one, but it wouldn't surprise me if a
    shortage of drives caused them to substitute one of equal, or greater,
    capacity.

    --
    Tom Stiller

    PGP fingerprint = 5108 DDB2 9761 EDE5 E7E3
    7BDA 71ED 6496 99C0 C7CF
    Tom Guest

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