300Gb hard drive formatting to 249Gb - boo.

From: Alex Teslik (alex_at_acatysmoof.com)
Date: 12/06/04

  • Next message: Jan Grant: "Re: 300Gb hard drive formatting to 249Gb - boo." 
    To: "List freebsd-questions" <freebsd-questions@freebsd.org>
Date: Mon, 6 Dec 2004 02:03:08 -0800

    Hello,

       I have recently installed a new 300Gb Maxtor hard disk:

    [root]/home/alex# dmesg -a | grep ^ad1
    ad1: 286188MB <Maxtor 6B300R0> [581463/16/63] at ata0-slave UDMA100

    This disk has a single partition on it and is formatted in compatibility mode:

    [root]/home/alex# disklabel ad1
    # /dev/ad1c:
    type: ESDI
    disk: ad1s1
    label:
    flags:
    bytes/sector: 512
    sectors/track: 63
    tracks/cylinder: 255
    sectors/cylinder: 16065
    cylinders: 36482
    sectors/unit: 586099332
    rpm: 3600
    interleave: 1
    trackskew: 0
    cylinderskew: 0
    headswitch: 0 # milliseconds
    track-to-track seek: 0 # milliseconds
    drivedata: 0

    8 partitions:
    # size offset fstype [fsize bsize bps/cpg]
      c: 586099332 0 unused 0 0 # (Cyl. 0 - 36482*)
      e: 586099332 0 4.2BSD 1024 8192 22 # (Cyl. 0 - 36482*)

    now, I understand that a Gigabyte to the Maxtor corporation is 300,000,000,000
    bytes. So, I would expect this disk to format to 279Gb based on the following
    math:

    [alex]/home/alex# bc
    bc 1.06
    Copyright 1991-1994, 1997, 1998, 2000 Free Software Foundation, Inc.
    This is free software with ABSOLUTELY NO WARRANTY.
    For details type `warranty'.

    (((300000000000 / 1024) /1024) /1024)
    279

    However, when I mount the drive it is formatted to 271Gb, 8Gb less than what I
    expected. This wouldn't be so bad except that the available space on the drive
    is only 249Gb. :(
    Is this right? I feel like I am missing something. Can someone help me
    understand this better? I would love to regain the 30Gb I feel I am missing if
    possible.

    [root]/home/alex# mount /dev/ad1s1e /1

    [root]/home/alex# df -h
    Filesystem Size Used Avail Capacity Mounted on
    /dev/da0s1a 97M 62M 27M 70% /
    /dev/da0s1e 7.7G 6.2G 938M 87% /usr
    /dev/ad0s1e 72G 66G 817M 99% /home
    procfs 4.0K 4.0K 0B 100% /proc
    /dev/ad1s1e 271G 1.0K 249G 0% /1

    [root]/home/alex# df
    Filesystem 1K-blocks Used Avail Capacity Mounted on
    /dev/da0s1a 99183 63614 27635 70% /
    /dev/da0s1e 8084746 6477062 960905 87% /usr
    /dev/ad0s1e 75744027 68847899 836606 99% /home
    procfs 4 4 0 100% /proc
    /dev/ad1s1e 284046628 1 261322897 0% /1

    I formatted this drive using the automatic settings in
    /stand/sysinstall->Index->Partitions.

    Thanks,
    Alex

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  • Next message: Jan Grant: "Re: 300Gb hard drive formatting to 249Gb - boo."

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