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how to access raw firewire disk - Mac Programming

How do you access a raw disk partition on a firewire disk under OSX? It looks like the /dev/rdiskNsN inode is only created when the disk has been mounted. So how else can a program get to an unmounted partition? It just seems a little scary to have to use the full disk /dev/rdiskN and programatically go through the partition table. For one, it wouldn't be hard to overrun the partition upper limit. Is there a better way? Does the raw inode for a partition on an internal disk disappear when the partition is unmounted? Or is that just a ...

  1. #1

    Default how to access raw firewire disk

    How do you access a raw disk partition on a firewire disk under OSX?

    It looks like the /dev/rdiskNsN inode is only created when the disk has
    been mounted. So how else can a program get to an unmounted partition?
    It just seems a little scary to have to use the full disk /dev/rdiskN
    and programatically go through the partition table. For one, it
    wouldn't be hard to overrun the partition upper limit.

    Is there a better way?

    Does the raw inode for a partition on an internal disk disappear when
    the partition is unmounted? Or is that just a property of an external
    (firewire) disk?

    Thanks for any info
    it's Guest

  2. #2

    Default Re: how to access raw firewire disk

    In article <west.earthlink.net>,
    it's not my father's unix <net> wrote:
     

    What are you really trying to do?

    meeroh

    --
    If this message helped you, consider buying an item
    from my wish list: <http://web.meeroh.org/wishlist>

    Miro Guest

  3. #3

    Default Re: how to access raw firewire disk

    Miro Jurisic wrote:
     
    >
    > What are you really trying to do?[/ref]

    xyyzy? 42? Do I need to show my membership card?

    Granted, my question was dripping with hints of criminal and seditious
    activity. But you don't really think I'm going to disclose such plans
    in public, do you?. So let's just say I became curious when I noticed
    the /dev entries for my external firewire disk partitions disappeared
    when unmounted. In order to justify posting in a group most likely to
    have an expert audience, I framed a rather general question in a
    programming context. I'll continue that general thread in c.s.m.s.

    In an attempt to fly under the radar of the Security Monitors, yet still
    justify the c.s.m.p.h. forum: does the system offer any help in
    enforcing partition boundaries when writing to an unmounted partition?
    Is there a function that explicitly gives the system the partition
    boundaries (because there's no "rdiskNsN" to do so implicitly). Or, if
    you are writing to an unmounted partition (via partition map offsets),
    do you just have to be careful?

    Does "unmounted partition" sound less suspicious then "raw disk"?
    it's Guest

  4. #4

    Default Re: how to access raw firewire disk

    it's not my father's unix wrote: 
    >
    > xyyzy? 42? Do I need to show my membership card?
    >
    > Granted, my question was dripping with hints of criminal and seditious
    > activity. But you don't really think I'm going to disclose such plans
    > in public, do you?.[/ref]

    dude, relax. it's quite common to ask "what are you trying to do."
    questioners often come to these groups thinking they've got their
    problem 90 percent solved, and just need an answer for the final 10
    percent. just as often, they are incorrect, and are barking up the
    wrong tree. you have to step back and look at the big picture to get a
    decent answer.
    Jhnny Guest

  5. #5

    Default Re: how to access raw firewire disk

    Jhnny Fvrt (it means "halo, then resonate") <com>
    wrote:
     
    > >
    > > xyyzy? 42? Do I need to show my membership card?
    > >
    > > Granted, my question was dripping with hints of criminal and seditious
    > > activity. But you don't really think I'm going to disclose such plans
    > > in public, do you?.[/ref]
    >
    > dude, relax. it's quite common to ask "what are you trying to do."
    > questioners often come to these groups thinking they've got their problem
    > 90 percent solved, and just need an answer for the final 10 percent. just
    > as often, they are incorrect, and are barking up the wrong tree. you have
    > to step back and look at the big picture to get a decent answer.[/ref]

    <http://www.codecomments.com/MAC_Applications/message171267.html>

    Disclaimer: I'm not 100% sure that URL applies, though the questions
    about /dev and 'raw disk' are a tip-off.
    Paul Guest

  6. #6

    Default Re: how to access raw firewire disk

     [/ref][/ref]

    Just use the 'dev' entries. Make some of your own by hand, if you need to.
    Make them in some other directory, if 'devfs' prevents us.
     

    I haven't see a UNIX in the last 20 years that didn't enforce partition boundaries.
    For OS X, see the 'pdisk' and 'fdisk' commands and man pages.

    Or, get the Darwin source and read the device drivers.
    Maybe the Darwin source also has the man page for disk(8),
    since 10.2.4 doesn't see to have one.
     

    They're both perfectly acceptable terms.
    I used to make image backups from raw partitions all the time.


    Mike Guest

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