How to find the number of unsed sectors? - Embedded

This is a discussion on How to find the number of unsed sectors? - Embedded ; Hello to all, Can any one please tell me how to find the no of used sectors from the hdd. Is there any linux command to find out that??...

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Thread: How to find the number of unsed sectors?

  1. How to find the number of unsed sectors?

    Hello to all,

    Can any one please tell me how to find the no of used sectors from the
    hdd. Is there any linux command to find out that??


  2. Re: How to find the number of unsed sectors?

    > Can any one please tell me how to find the no of used sectors from the
    > hdd. Is there any linux command to find out that??
    >


    Sectors on a HD are not marked "used" in any way.

    On a HD there can be lots of partitions.
    The partition table indicates what sectors are assigned to what
    partitions. There might be sectors that are not assigned to any
    partition. Same can be called "unused".

    In each partition there can be a file system. Linux provides drivers for
    a lot of different file systems as a standard and everybody can create a
    new one if he likes.

    Each kind of file system has it's own method to define which sectors are
    assigned to what kind of information (e.g. to the file allocation table,
    to the main directory, to a subdirectory, to a file, or to the chain of
    unused blocks. That was said with an FAT file system in mind, other file
    systems can be much more complicated.

    So the short answer is: you can't.

    -Michael

  3. Re: How to find the number of unsed sectors?

    Nutty wrote:
    > Hello to all,
    >
    > Can any one please tell me how to find the no of used sectors from the
    > hdd. Is there any linux command to find out that??
    >


    How about getting the book on kernel internals instead
    of milking unconnected information fragments here in the
    newsgroup?

    What you want to do is very prone to crash the whole system
    unless the programmer understands what's going on inside
    the kernel.

    --

    Tauno Voipio
    tauno voipio (at) iki fi

  4. Re: How to find the number of unsed sectors?

    Nutty wrote:

    > Hello to all,
    >
    > Can any one please tell me how to find the no of used sectors from the
    > hdd. Is there any linux command to find out that??


    This depends on the partition structure and the filesystems
    on each partition.

    For a mounted filesystem you could use df to get a
    snapshot of the usage. It does not necessarily map
    to actual sectors on the disk.

    ~$ df
    Filesystem 1K-blocks Used Available Use% Mounted on
    /dev/hda3 79013284 47764916 31248368 61% /

    In this example, there are 47764916 used blocks in this
    specific partition. One block is two sectors on this disk.

    Kind regards,

    Iwo


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