How to determine the size of cylinder? - Redhat

This is a discussion on How to determine the size of cylinder? - Redhat ; Dear experts, I have a good technical question for you. From the newsgroups: "From: Gary Boswell (gboswell@dormnet.stu1.uconn.edu) Subject: Hard Drive > 500 mb FAQ Back in ancient times computers had a limitation in the BIOS of the following: cylinders = ...

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Thread: How to determine the size of cylinder?

  1. How to determine the size of cylinder?

    Dear experts,

    I have a good technical question for you.

    From the newsgroups:

    "From: Gary Boswell (gboswell@dormnet.stu1.uconn.edu)
    Subject: Hard Drive > 500 mb FAQ

    Back in ancient times computers had a limitation in the BIOS of the following:
    cylinders = 1024
    heads = 16
    sectors = 63
    * 512
    -----------
    or 528,482,304 bytes
    Due to these limitations the maximum size of a hard drive was:
    528 chkdisk mb
    503 CMOS mb"


    My question is:
    - for a given hard drive, how can I tell the size of the cylinder?

    In either Redhat, or Windows XP?

    Thanks

  2. Re: How to determine the size of cylinder?

    Pi*R^2*H

    For computers, see Google
    hard drive cylinders ... diving cylinders scuba cylinders
    cng compressors hydrolic cylinders hydralic cylinders cng
    cylinders cng india cng nec hard drive cylinders wax
    cylinders area ...
    www.faber-italy.com/hard-drive-cylinders.html - 5k -
    Cached - Similar pages


    Hard Drive Size Barriers, In Depth ... Translation works by
    dividing the number of cylinders or a hard drive by a binary
    number such as 2, 4, 8 or 16, and then multiplying the
    number of heads by the ...
    www.dewassoc.com/kbase/hard_drives/
    hard_drive_size_barriers.htm - 70k - Cached - Similar pages


    The History and Development of Hard Drive Technologies ...
    today still rely on this original CMOS drive type scheme ...
    a problem with more than two hard drives and ... limits to
    recognizing more than 1024 cylinders, 16 heads ...
    www.actionfront.com/hdtech1.html - 20k - Cached -
    Similar pages


    What is hard disk? - A Word Definition From the Webopedia
    Computer ... ... called a cylinder. For example, a typical
    84 megabyte hard disk for a PC might have two platters (four
    sides) and 1,053 cylinders. ...
    www.webopedia.com/TERM/h/hard_disk.html - 48k -
    Cached - Similar pages


    BIOS Limitations ... with the "13th bit". The 13th bit is
    needed to provide support for a drive having 4096 or more
    cylinders. The chart below displays ...
    www.seagate.com/support/kb/disc/bioslmt.html - 27k -
    Cached - Similar pages


    2

    wrote in message
    news:672ceaed.0411282028.1b8dc772@posting.google.c om...
    | Dear experts,
    |
    | I have a good technical question for you.
    |
    | From the newsgroups:
    |
    | "From: Gary Boswell (gboswell@dormnet.stu1.uconn.edu)
    | Subject: Hard Drive > 500 mb FAQ
    |
    | Back in ancient times computers had a limitation in the
    BIOS of the following:
    | cylinders = 1024
    | heads = 16
    | sectors = 63
    | * 512
    | -----------
    | or 528,482,304 bytes
    | Due to these limitations the maximum size of a hard drive
    was:
    | 528 chkdisk mb
    | 503 CMOS mb"
    |
    |
    | My question is:
    | - for a given hard drive, how can I tell the size of the
    cylinder?
    |
    | In either Redhat, or Windows XP?
    |
    | Thanks



  3. Re: How to determine the size of cylinder?

    linuxquestion@yahoo.com wrote:

    > Dear experts,
    >
    > I have a good technical question for you.
    >
    > From the newsgroups:
    >
    > "From: Gary Boswell (gboswell@dormnet.stu1.uconn.edu)
    > Subject: Hard Drive > 500 mb FAQ
    >
    > Back in ancient times computers had a limitation in the BIOS of the following:
    > cylinders = 1024
    > heads = 16
    > sectors = 63
    > * 512
    > -----------
    > or 528,482,304 bytes
    > Due to these limitations the maximum size of a hard drive was:
    > 528 chkdisk mb
    > 503 CMOS mb"
    >
    >
    > My question is:
    > - for a given hard drive, how can I tell the size of the cylinder?
    >
    > In either Redhat, or Windows XP?
    >
    > Thanks


    All but ancient HDs use ZBR, which means that the number of sectors on
    a cylinder varies. Outer cylinders have more sectors than inner ones.
    --
    Cheers, Bob

  4. Re: How to determine the size of cylinder?

    The sure way is to fire up the browser and then look up the specs for
    the drive in question on the manufacturers web site.

    Bob Willard wrote:

    > linuxquestion@yahoo.com wrote:
    >
    >> Dear experts,
    >>
    >> I have a good technical question for you.
    >> From the newsgroups:
    >>
    >> "From: Gary Boswell (gboswell@dormnet.stu1.uconn.edu)
    >> Subject: Hard Drive > 500 mb FAQ
    >> Back in ancient times computers had a limitation in the BIOS of the
    >> following: cylinders = 1024
    >> heads = 16
    >> sectors = 63
    >> * 512
    >> -----------
    >> or 528,482,304 bytes Due to these limitations the maximum size
    >> of a hard drive was:
    >> 528 chkdisk mb
    >> 503 CMOS mb"
    >>
    >>
    >> My question is:
    >> - for a given hard drive, how can I tell the size of the cylinder?
    >>
    >> In either Redhat, or Windows XP?
    >>
    >> Thanks

    >
    >
    > All but ancient HDs use ZBR, which means that the number of sectors on
    > a cylinder varies. Outer cylinders have more sectors than inner ones.



  5. Re: How to determine the size of cylinder?

    Bob I wrote:
    > The sure way is to fire up the browser and then look up the specs for
    > the drive in question on the manufacturers web site.
    >

    What an interesting idea!

    However, Maxtor do not tell me the number of cylinder size or the number
    of cylinders on my four KU018L2 hard drives. They tell me the drives have
    one disk with two heads and two recording surfaces. That there are 512
    bytes per sector. Other models have 2 or 4 disks, so 4 or 8 recording
    surfaces. (With my two 6Y080P0 drives, they tell me that they have 512
    bytes per block, and it is logically CHS 16383/16/63, but I do not know
    what that really means since they have models from 60GBytes to 200GBytes
    with the same specification of logical CHS. They obviously do not take the
    CHS specification very seriously.)

    So clearly a cylinder has two tracks, if that is what you mean by cylinder
    size. The other models have 4 track or 8 track cylinders.

    But so what? How many sectors are on a track? That very clearly varies. If
    I try to read an entire drive; e.g., running badblocks in verbose mode on
    it, I can see that it slows down from around 57 Megabytes/second at the
    outside edge to about 31 Megabytes/second at the center. So clearly the
    number of sectors/track is not constant, but monotonically decreasing.

    --
    .~. Jean-David Beyer Registered Linux User 85642.
    /V\ Registered Machine 241939.
    /( )\ Shrewsbury, New Jersey http://counter.li.org
    ^^-^^ 15:45:00 up 37 days, 18:40, 3 users, load average: 4.11, 4.15, 4.10


  6. Re: How to determine the size of cylinder?

    linuxquestion@yahoo.com wrote in
    news:672ceaed.0411282028.1b8dc772@posting.google.c om:

    > Dear experts,
    >
    > I have a good technical question for you.
    >
    > From the newsgroups:
    >
    > "From: Gary Boswell (gboswell@dormnet.stu1.uconn.edu)
    > Subject: Hard Drive > 500 mb FAQ
    >
    > Back in ancient times computers had a limitation in the BIOS of the
    > following:
    > cylinders = 1024
    > heads = 16
    > sectors = 63
    > * 512
    > -----------
    > or 528,482,304 bytes
    > Due to these limitations the maximum size of a hard drive was:
    > 528 chkdisk mb
    > 503 CMOS mb"
    >
    >
    > My question is:
    > - for a given hard drive, how can I tell the size of the cylinder?
    >
    > In either Redhat, or Windows XP?


    You cannot. Modern IDE drives use logical block addressing which masks the
    physical layout of the disk from the user. The old CHS method is
    maintained for legacy only and only allows you to use a portion of the
    drive's capacity. Furthermore, the notion of Cylinder, Head, and Sector
    has nothing to do with the physical disk attributes when using the CHS
    values provided by the drive.

    You may get some information from the disk vendor's OEM Data Sheet. For
    instance, Hitachi sites varying recording zone densities for tracks along
    with some other information that should allow you to determine the sectors
    per track and then the sectors per cylinder. You will need to do this
    off-line calculation for each model and capacity you employ as these
    values may (and often do) change.

    --
    - Mark ->
    --

  7. Re: How to determine the size of cylinder?

    Jean-David Beyer wrote on 11/29/2004 13:02:
    > But so what? How many sectors are on a track? That very clearly varies.
    > If I try to read an entire drive; e.g., running badblocks in verbose
    > mode on it, I can see that it slows down from around 57 Megabytes/second
    > at the outside edge to about 31 Megabytes/second at the center. So
    > clearly the number of sectors/track is not constant, but monotonically
    > decreasing.


    Of course it does. There is more space on the outer tracks...
    This is called zone-bit recording:
    http://www.pcguide.com/ref/hdd/geom/tracksZBR-c.html

    -Joe

  8. Re: How to determine the size of cylinder?

    Dear user:
    I am wondering why you need this!
    On old IDE drives the CHS information was written on the disk... and was kae
    anyway, but useful for BIOS setting.

    For a long time (over 10 years) IDE/ATA has a query command to query the CHS
    information: the host can request and get this info from the disk.

    There even was a command to change it (YES!).

    Today, the data is accessed by LBA (logical block address).
    A logical block is still often 512 bytes of data, but in my opinion it
    should be bumped to a higher number, like 2k (2048 bytes).

    So you really do not need to know the number of CHS on your disk excepted
    for curiosity.
    ----

    linuxquestion@yahoo.com wrote:
    > Dear experts,
    > I have a good technical question for you.



  9. Re: How to determine the size of cylinder?

    -----BEGIN PGP SIGNED MESSAGE-----
    Hash: SHA1

    linuxquestion@yahoo.com wrote:
    > Dear experts,

    [snip]
    > - for a given hard drive, how can I tell the size of the cylinder?


    For the purposes of partition placement, fdisk will tell you the 'size of the
    cylinder' of any installed hard drive

    ~ $ sudo /sbin/fdisk -l /dev/hda

    Disk /dev/hda: 20.4 GB, 20490559488 bytes
    255 heads, 63 sectors/track, 2491 cylinders
    Units = cylinders of 16065 * 512 = 8225280 bytes

    Or, you can examine the contents of /proc/ide//geometry

    ~ $ cat /proc/ide/hda/geometry
    physical 39703/16/63
    logical 2491/255/63



    - --
    Lew Pitcher

    Master Codewright & JOAT-in-training | GPG public key available on request
    Registered Linux User #112576 (http://counter.li.org/)
    Slackware - Because I know what I'm doing.
    -----BEGIN PGP SIGNATURE-----
    Version: GnuPG v1.2.4 (GNU/Linux)
    Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org

    iD8DBQFBq+GRagVFX4UWr64RArwgAJoDCqbdzil93NAmM2f24j U8TVTiVwCgjAeX
    iOH3RBYqnpBpPK4zmct9+nk=
    =Kqi7
    -----END PGP SIGNATURE-----

  10. Re: How to determine the size of cylinder?

    linuxquestion@yahoo.com writes:
    > My question is:
    > - for a given hard drive, how can I tell the size of the cylinder?


    I hope you realize that for most modern hard drive this question is
    meaningless. That is if you really want to know what you're asking.

    Since the hard drive changes the size of the cylinders to pack more
    data in the outer cylinders. You could try to ask what is the size of
    a given cylinder? But it would not serve much, because modern hard
    drives remap bad sectors on other cylinder "transparently", and use
    really only LBA, even if the CHS addressing is still supported for
    legacy.

    --
    __Pascal Bourguignon__ http://www.informatimago.com/
    The world will now reboot; don't bother saving your artefacts.

  11. Re: How to determine the size of cylinder?

    Lew Pitcher wrote in
    news:BjRqd.12106$Ad3.762097@news20.bellglobal.com:

    > [snip]
    >> - for a given hard drive, how can I tell the size of the cylinder?

    [snip]
    > Or, you can examine the contents of /proc/ide//geometry
    >
    > ~ $ cat /proc/ide/hda/geometry
    > physical 39703/16/63


    This is bogus, of course, and has nothing to do with the physical number
    of cylinders, heads, or or sectors on the disk. Only the vendor's data
    sheet will give you the physical information.

    --
    - Mark ->
    --

  12. Re: How to determine the size of cylinder?

    AnonymousFC3 wrote in
    news:HdWdnRv8m7bQQDbcRVn-vQ@comcast.com:

    > For a long time (over 10 years) IDE/ATA has a query command to query the
    > CHS information: the host can request and get this info from the disk.


    But it will not relate to the physical parameters of a modern disk.

    --
    - Mark ->
    --

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