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| BSD BSD, sometimes called Berkeley Unix, is a Unix operating system developed by the Computer Systems Research Group of the UC Berkeley. |
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#1
01-16-2013
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OpenBSD fdisk - Linux fdisk compatibility ?
Hello, MBR partition table made by linux fdisk looks certainly not correct when printed by openbsd fdisk: Partition table created on linux (centos 6.3): Code:
# fdisk -l /dev/sdc Disk /dev/sdc: 10.7 GB, 10737418240 bytes 255 heads, 63 sectors/track, 1305 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x61f77373 Device Boot Start End Blocks Id System /dev/sdc1 1 131 1052226 83 Linux /dev/sdc2 132 262 1052257+ 83 Linux /dev/sdc4 263 1305 8377897+ 5 Extended /dev/sdc5 263 523 2096451 8e Linux LVM /dev/sdc6 524 784 2096451 8e Linux LVM /dev/sdc7 785 1045 2096451 a6 OpenBSD Same disk on OpenBSD (5.2): Code:
# fdisk sd1
Disk: sd1 geometry: 1305/255/63 [20971520 Sectors]
Offset: 0 Signature: 0xAA55
Starting Ending LBA Info:
#: id C H S - C H S [ start: size ]
-------------------------------------------------------------------------------
0: 83 0 1 1 - 130 254 63 [ 63: 2104452 ] Linux files*
1: 83 131 0 1 - 261 254 63 [ 2104515: 2104515 ] Linux files*
2: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
3: 05 262 0 1 - 1304 254 63 [ 4209030: 16755795 ] Extended DOS
Offset: 4209030 Signature: 0xAA55
Starting Ending LBA Info:
#: id C H S - C H S [ start: size ]
-------------------------------------------------------------------------------
0: 8E 262 1 1 - 522 254 63 [ 4209093: 4192902 ] Linux LVM
1: 05 523 0 1 - 783 254 63 [ 8401995: 4192965 ] Extended DOS
2: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
3: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
Offset: 8401995 Signature: 0xAA55
Starting Ending LBA Info:
#: id C H S - C H S [ start: size ]
-------------------------------------------------------------------------------
0: 8E 523 1 1 - 783 254 63 [ 8402058: 4192902 ] Linux LVM
1: 05 784 0 1 - 1044 254 63 [ 12594960: 4192965 ] Extended DOS
2: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
3: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
Offset: 12594960 Signature: 0xAA55
Starting Ending LBA Info:
#: id C H S - C H S [ start: size ]
-------------------------------------------------------------------------------
0: A6 784 1 1 - 1044 254 63 [ 12595023: 4192902 ] OpenBSD
1: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
2: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
3: 00 0 0 0 - 0 0 0 [ 0: 0 ] unusedOpenBSD fdisk shows separate 4 partition block for extended partition, but result above shows 4 4-partition blocks(instead of 2). If I create same partition table on OpenBSD from scratch: Code:
# fdisk sd1
Disk: sd1 geometry: 1305/255/63 [20971520 Sectors]
Offset: 0 Signature: 0x0
Starting Ending LBA Info:
#: id C H S - C H S [ start: size ]
-------------------------------------------------------------------------------
0: 83 0 1 1 - 130 254 63 [ 63: 2104452 ] Linux files*
1: 83 131 0 1 - 261 254 63 [ 2104515: 2104515 ] Linux files*
2: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
3: 05 262 0 1 - 1304 254 63 [ 4209030: 16755795 ] Extended DOS
Offset: 4209030 Signature: 0xAA55
Starting Ending LBA Info:
#: id C H S - C H S [ start: size ]
-------------------------------------------------------------------------------
0: 8E 262 1 1 - 522 254 63 [ 4209093: 4192902 ] Linux LVM
1: 83 523 1 1 - 783 254 63 [ 8402058: 4192902 ] Linux files*
2: A6 784 1 1 - 1044 254 63 [ 12595023: 4192902 ] OpenBSD
3: 00 0 0 0 - 0 0 0 [ 0: 0 ] unusedNow if we connect that disk to linux partition table is not recognized: Code:
# fdisk -l /dev/sdb Disk /dev/sdb: 10.7 GB, 10737418240 bytes 255 heads, 63 sectors/track, 1305 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 # Why this is happening ? How do I create partition table compatible between two OSes ? thanks Vilius M. |
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#2
01-16-2013
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The first partition table(s) has the correct - whatever this means - standard structure as introduced, I think, by Microsoft (?) centuries ago. Which is boot sector with partition entries, one of which points to a chain of partition tables each consisting of one entry and a link entry.
I've spent ages fiddling around with non-standard structures in extended partitions without any luck, esp. when it comes to coexistence of several OSs on the same disk. On the other hand, linux should at least recognize the partition entries in the boot sector of your experiment. Mysterious. Not sure what the zero disk identifier does. Did you try to use another partition tool (cfdisk, parted, sfdisk)? Did you try to read the sectors binarily (od, hexdump)? BTW - you are fdisking sdc in your first quote and sdb in the second... |
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#3
01-16-2013
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Quote:
I did few more experiments - and yes looks like incompatibility happens in extended partition logical drives.... V |
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