パッケージやバージョンによっては違いあると思いますンで、あくまで一例でござい。SystemRescueCd 3.7.1 での確認でありんす。
仕様じゃなくて、あくまで default の話。
- 表示・指定がシリンダ番号（1から）ではなく、セクタ番地（0から）
- 第1パーティション新規作成の offset（開始位置）デフォルトはセクタ2048（従来はHDならセクタ63とか）
- offset 8192 のSDカードなどでも offset 2048 がデフォルト（※ 再作成時など注意）
-u=cylindersを指定するとシリンダ数表示-c=dos指定で C/H/S 設定表示-c=dos指定では offset 63 がデフォルト（H/S 255/63 の場合）
まぁ普通にHDなら問題ないかもですけど。USBメモリやSDカードの場合は注意しといた方がいいかなってかんじです。
下記は SystemRescueCd 3.7.1、4GB microSDHC 及び 16GB USBフラッシュメモリ での確認です。
- バージョンとヘルプ
root@sysresccd /root % fdisk -v fdisk from util-linux 2.22.2 root@sysresccd /root % fdisk -h Usage: fdisk [options] <disk> change partition table fdisk [options] -l <disk> list partition table(s) fdisk -s <partition> give partition size(s) in blocks Options: -b <size> sector size (512, 1024, 2048 or 4096) -c[=<mode>] compatible mode: 'dos' or 'nondos' (default) -h print this help text -u[=<unit>] display units: 'cylinders' or 'sectors' (default) -v print program version -C <number> specify the number of cylinders -H <number> specify the number of heads -S <number> specify the number of sectors per track
4GB microSDHC
fdisk -l- 表示がセクタ番地。最近のはほとんどこれかな。
root@sysresccd /root % fdisk -l /dev/sdb Disk /dev/sdb: 3965 MB, 3965714432 bytes, 7745536 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sdb1 * 8192 7741439 3866624 b W95 FAT32
-u=cylindersでシリンダ番号で表示、-c=dosで C/H/S 設定表示
root@sysresccd /root % fdisk -lu=cylinders -c=dos /dev/sdb Disk /dev/sdb: 3965 MB, 3965714432 bytes, 7745536 sectors 128 heads, 63 sectors/track, 960 cylinders Units = cylinders of 8064 * 512 = 4128768 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sdb1 * 2 960 3866624 b W95 FAT32
- 普通に fdisk 実行
root@sysresccd /root % dd if=/dev/zero of=/dev/sdb bs=512 count=8194
8194+0 records in
8194+0 records out
4195328 bytes (4.2 MB) copied, 13.3538 s, 314 kB/s
root@sysresccd /root % fdisk /dev/sdb
Welcome to fdisk (util-linux 2.22.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0xa144c6af.
Command (m for help): p
Disk /dev/sdb: 3965 MB, 3965714432 bytes, 7745536 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xa144c6af
Device Boot Start End Blocks Id System
Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): p
Partition number (1-4, default 1):
Using default value 1
First sector (2048-7745535, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-7745535, default 7745535):
Using default value 7745535
Partition 1 of type Linux and of size 3.7 GiB is set
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): b
Changed system type of partition 1 to b (W95 FAT32)
Command (m for help): a
Partition number (1-4): 1
Command (m for help): p
Disk /dev/sdb: 3965 MB, 3965714432 bytes, 7745536 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xa144c6af
Device Boot Start End Blocks Id System
/dev/sdb1 * 2048 7745535 3871744 b W95 FAT32
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: If you have created or modified any DOS 6.x
partitions, please see the fdisk manual page for additional
information.
Syncing disks.
- デフォルトのままでの実行後の内容はこんなかんじ。Windows 7 と同じ
root@sysresccd /root % fdisk -l /dev/sdb Disk /dev/sdb: 3965 MB, 3965714432 bytes, 7745536 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xa144c6af Device Boot Start End Blocks Id System /dev/sdb1 * 2048 7745535 3871744 b W95 FAT32 root@sysresccd /root % fdisk -lu=cylinders -c=dos /dev/sdb Disk /dev/sdb: 3965 MB, 3965714432 bytes, 7745536 sectors 122 heads, 62 sectors/track, 1024 cylinders Units = cylinders of 7564 * 512 = 3872768 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xa144c6af Device Boot Start End Blocks Id System /dev/sdb1 * 1 1024 3871744 b W95 FAT32
- 旧式（DOS形式）指定して実行
root@sysresccd /root % dd if=/dev/zero of=/dev/sdb bs=512 count=2050
2050+0 records in
2050+0 records out
1049600 bytes (1.0 MB) copied, 5.98311 s, 175 kB/s
root@sysresccd /root % fdisk -u=cylinders -c=dos /dev/sdb
Welcome to fdisk (util-linux 2.22.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0xb8926659.
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (with command 'c').
WARNING: cylinders as display units are deprecated. Use command 'u' to
change units to sectors.
Command (m for help): p
Disk /dev/sdb: 3965 MB, 3965714432 bytes, 7745536 sectors
122 heads, 62 sectors/track, 1024 cylinders
Units = cylinders of 7564 * 512 = 3872768 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xb8926659
Device Boot Start End Blocks Id System
Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): p
Partition number (1-4, default 1): 1
First cylinder (1-1024, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-1024, default 1024):
Using default value 1024
Partition 1 of type Linux and of size 3.7 GiB is set
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): b
Changed system type of partition 1 to b (W95 FAT32)
Command (m for help): a
Partition number (1-4): 1
Command (m for help): p
Disk /dev/sdb: 3965 MB, 3965714432 bytes, 7745536 sectors
122 heads, 62 sectors/track, 1024 cylinders
Units = cylinders of 7564 * 512 = 3872768 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xb8926659
Device Boot Start End Blocks Id System
/dev/sdb1 * 1 1024 3872737 b W95 FAT32
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: If you have created or modified any DOS 6.x
partitions, please see the fdisk manual page for additional
information.
Syncing disks.
- DOS形式指定の内容こんなかんじ。offset は C/H/S のセクタ数に合わせて、シリンダ数が1024以下に。
root@sysresccd /root % fdisk -l /dev/sdb Disk /dev/sdb: 3965 MB, 3965714432 bytes, 7745536 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xb8926659 Device Boot Start End Blocks Id System /dev/sdb1 * 62 7745535 3872737 b W95 FAT32 root@sysresccd /root % fdisk -lu=cylinders -c=dos /dev/sdb Disk /dev/sdb: 3965 MB, 3965714432 bytes, 7745536 sectors 122 heads, 62 sectors/track, 1024 cylinders Units = cylinders of 7564 * 512 = 3872768 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xb8926659 Device Boot Start End Blocks Id System /dev/sdb1 * 1 1024 3872737 b W95 FAT32
16GB USBフラッシュメモリ
- 普通に fdisk 実行
root@sysresccd /root % dd if=/dev/zero of=/dev/sdc bs=512 count=2050
2050+0 records in
2050+0 records out
1049600 bytes (1.0 MB) copied, 2.55526 s, 411 kB/s
root@sysresccd /root % fdisk /dev/sdc
Welcome to fdisk (util-linux 2.22.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0x6dd6ecfc.
Command (m for help): p
Disk /dev/sdc: 16.1 GB, 16079781888 bytes, 31405824 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x6dd6ecfc
Device Boot Start End Blocks Id System
Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): p
Partition number (1-4, default 1):
Using default value 1
First sector (2048-31405823, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-31405823, default 31405823):
Using default value 31405823
Partition 1 of type Linux and of size 15 GiB is set
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): c
Changed system type of partition 1 to c (W95 FAT32 (LBA))
Command (m for help): a
Partition number (1-4): 1
Command (m for help): p
Disk /dev/sdc: 16.1 GB, 16079781888 bytes, 31405824 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x6dd6ecfc
Device Boot Start End Blocks Id System
/dev/sdc1 * 2048 31405823 15701888 c W95 FAT32 (LBA)
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: If you have created or modified any DOS 6.x
partitions, please see the fdisk manual page for additional
information.
Syncing disks.
- デフォルトのままでの実行後の内容はこんなかんじ。Windows 7 と同じ
root@sysresccd /root % fdisk -l /dev/sdc Disk /dev/sdc: 16.1 GB, 16079781888 bytes, 31405824 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x6dd6ecfc Device Boot Start End Blocks Id System /dev/sdc1 * 2048 31405823 15701888 c W95 FAT32 (LBA) root@sysresccd /root % fdisk -l -u=cylinders -c=dos /dev/sdc Disk /dev/sdc: 16.1 GB, 16079781888 bytes, 31405824 sectors 56 heads, 32 sectors/track, 15334 cylinders Units = cylinders of 2048 * 512 = 1048576 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x6dd6ecfc Device Boot Start End Blocks Id System /dev/sdc1 * 2 15335 15701888 c W95 FAT32 (LBA)
- 旧式（DOS形式）指定して実行
root@sysresccd /root % dd if=/dev/zero of=/dev/sdc bs=512 count=2050
2050+0 records in
2050+0 records out
1049600 bytes (1.0 MB) copied, 3.54364 s, 296 kB/s
root@sysresccd /root % fdisk -u=cylinders -c=dos /dev/sdc
Welcome to fdisk (util-linux 2.22.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0xd8682994.
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (with command 'c').
WARNING: cylinders as display units are deprecated. Use command 'u' to
change units to sectors.
Command (m for help): p
Disk /dev/sdc: 16.1 GB, 16079781888 bytes, 31405824 sectors
64 heads, 32 sectors/track, 15334 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xd8682994
Device Boot Start End Blocks Id System
Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p):
Using default response p
Partition number (1-4, default 1):
Using default value 1
First cylinder (1-15334, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-15334, default 15334):
Using default value 15334
Partition 1 of type Linux and of size 15 GiB is set
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): c
Changed system type of partition 1 to c (W95 FAT32 (LBA))
Command (m for help): a
Partition number (1-4): 1
Command (m for help): p
Disk /dev/sdc: 16.1 GB, 16079781888 bytes, 31405824 sectors
64 heads, 32 sectors/track, 15334 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xd8682994
Device Boot Start End Blocks Id System
/dev/sdc1 * 1 15334 15702000 c W95 FAT32 (LBA)
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: If you have created or modified any DOS 6.x
partitions, please see the fdisk manual page for additional
information.
Syncing disks.
- DOS形式指定の内容こんなかんじ。offset は C/H/S のセクタ数に合わせて、H/S が 64/32、シリンダ数は1024以下にならない
root@sysresccd /root % fdisk -l /dev/sdc Disk /dev/sdc: 16.1 GB, 16079781888 bytes, 31405824 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xd8682994 Device Boot Start End Blocks Id System /dev/sdc1 * 32 31404031 15702000 c W95 FAT32 (LBA) root@sysresccd /root % fdisk -l -u=cylinders -c=dos /dev/sdc Disk /dev/sdc: 16.1 GB, 16079781888 bytes, 31405824 sectors 64 heads, 32 sectors/track, 15334 cylinders Units = cylinders of 2048 * 512 = 1048576 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xd8682994 Device Boot Start End Blocks Id System /dev/sdc1 * 1 15334 15702000 c W95 FAT32 (LBA)
※ 旧式指定で 160GB HD（イメージ）の場合は offset 63(H/S 255/63) となってました。
いわゆるオサーンの「レガシー」な話でありますた。orz
ほなねん
