Hi, the first entry of my partition table is:
$ sudo hexdump -Cv -n 16 -s 446 /dev/sda
000001be 80 01 01 00 83 fe ff ff 3f 00 00 00 81 1c 20 03 |........?..... .|
(-Cv describe the output format, -n 16 asks for 16 bytes and -s 446 skips the first 446 bytes)
You can see that my first partition is a primary Linux partition and that this partition begin at sector 63 (see for example here for the structure of the partition table).
I would then expect that except for the first 63 sectors and the other partitions, /dev/sda1 and /dev/sda are exactly the same.
But this is not the case, the sector #2 of /dev/sda1 is not exactly the same as the sector #65 of /dev/sda (but they are very similar, only 16 bytes are different):
$ sudo hexdump -Cv -n 512 -s 65b /dev/sda
00008200 00 20 19 00 90 03 64 00 2d 00 05 00 5a 2f 56 00 |. ....d.-...Z/V.|
00008210 b6 b1 16 00 00 00 00 00 02 00 00 00 02 00 00 00 |................|
00008220 00 80 00 00 00 80 00 00 00 20 00 00 d8 38 ee 4c |......... ...8.L|
00008230 9a 01 ef 4c 05 00 24 00 53 ef 01 00 01 00 00 00 |...L..$.S.......|
00008240 59 23 e9 4c 00 4e ed 00 00 00 00 00 01 00 00 00 |Y#.L.N..........|
00008250 00 00 00 00 0b 00 00 00 00 01 00 00 3c 00 00 00 |............<...|
00008260 42 02 00 00 7b 00 00 00 85 23 eb f2 71 67 44 f5 |B...{....#..qgD.|
00008270 bb 8f 6f f2 3a 59 ff 4d 55 62 75 6e 74 75 00 00 |..o.:Y.MUbuntu..|
00008280 00 00 00 00 00 00 00 00 2f 75 62 75 6e 74 75 00 |......../ubuntu.|
00008290 d8 3c df 5d 00 88 ff ff 52 d0 ef 1d 00 00 00 00 |.<.]....R.......|
000082a0 c0 40 51 b6 00 88 ff ff 00 4e c8 bb 00 88 ff ff |
[email protected]......|
000082b0 c0 f6 86 b8 00 88 ff ff 30 2e 0d a0 ff ff ff ff |........0.......|
000082c0 38 3d df 5d 00 88 ff ff 00 00 00 00 00 00 fe 03 |8=.]............|
000082d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000082e0 08 00 00 00 00 00 00 00 00 00 00 00 8a 53 d3 0e |.............S..|
000082f0 7c 7a 43 e4 8b fb ca e0 72 b7 fa c8 01 01 00 00 ||zC.....r.......|
00008300 00 00 00 00 00 00 00 00 16 4c 47 4b 0a f3 03 00 |.........LGK....|
00008310 04 00 00 00 00 00 00 00 00 00 00 00 fe 7f 00 00 |................|
00008320 24 b7 0c 00 fe 7f 00 00 01 00 00 00 22 37 0d 00 |$..........."7..|
00008330 ff 7f 00 00 01 00 00 00 23 37 0d 00 00 00 00 00 |........#7......|
00008340 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 08 |................|
00008350 00 00 00 00 00 00 00 00 00 00 00 00 1c 00 1c 00 |................|
00008360 01 00 00 00 e9 7f 00 00 00 00 00 00 00 00 00 00 |................|
00008370 00 00 00 00 04 00 00 00 9f 7d bb 00 00 00 00 00 |.........}......|
00008380 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00008390 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000083a0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000083b0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000083c0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000083d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000083e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000083f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
versus
$ sudo hexdump -Cv -n 512 -s 2b /dev/sda1
00000400 00 20 19 00 90 03 64 00 2d 00 05 00 5a 2f 56 00 |. ....d.-...Z/V.|
00000410 b6 b1 16 00 00 00 00 00 02 00 00 00 02 00 00 00 |................|
00000420 00 80 00 00 00 80 00 00 00 20 00 00 df 76 ef 4c |......... ...v.L|
00000430 df 76 ef 4c 06 00 24 00 53 ef 01 00 01 00 00 00 |.v.L..$.S.......|
00000440 59 23 e9 4c 00 4e ed 00 00 00 00 00 01 00 00 00 |Y#.L.N..........|
00000450 00 00 00 00 0b 00 00 00 00 01 00 00 3c 00 00 00 |............<...|
00000460 46 02 00 00 7b 00 00 00 85 23 eb f2 71 67 44 f5 |F...{....#..qgD.|
00000470 bb 8f 6f f2 3a 59 ff 4d 55 62 75 6e 74 75 00 00 |..o.:Y.MUbuntu..|
00000480 00 00 00 00 00 00 00 00 2f 75 62 75 6e 74 75 00 |......../ubuntu.|
00000490 d8 3c df 5d 00 88 ff ff 52 d0 ef 1d 00 00 00 00 |.<.]....R.......|
000004a0 c0 40 51 b6 00 88 ff ff 00 4e c8 bb 00 88 ff ff |
[email protected]......|
000004b0 c0 f6 86 b8 00 88 ff ff 30 2e 0d a0 ff ff ff ff |........0.......|
000004c0 38 3d df 5d 00 88 ff ff 00 00 00 00 00 00 fe 03 |8=.]............|
000004d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000004e0 08 00 00 00 00 00 00 00 00 00 00 00 8a 53 d3 0e |.............S..|
000004f0 7c 7a 43 e4 8b fb ca e0 72 b7 fa c8 01 01 00 00 ||zC.....r.......|
00000500 00 00 00 00 00 00 00 00 16 4c 47 4b 0a f3 03 00 |.........LGK....|
00000510 04 00 00 00 00 00 00 00 00 00 00 00 fe 7f 00 00 |................|
00000520 24 b7 0c 00 fe 7f 00 00 01 00 00 00 22 37 0d 00 |$..........."7..|
00000530 ff 7f 00 00 01 00 00 00 23 37 0d 00 00 00 00 00 |........#7......|
00000540 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 08 |................|
00000550 00 00 00 00 00 00 00 00 00 00 00 00 1c 00 1c 00 |................|
00000560 01 00 00 00 e9 7f 00 00 00 00 00 00 00 00 00 00 |................|
00000570 00 00 00 00 04 00 00 00 a3 7d bb 00 00 00 00 00 |.........}......|
00000580 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00000590 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000005a0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000005b0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000005c0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000005d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000005e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000005f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
For example in the third line, there is a 8.L in the first hexdump and v.L in the second.
Why are there differences?
