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Re: MBR partitioning, and content after partition table but before first partition




David Christensen composed on 2017-03-08 21:46 (UTC-0800):
...
Examining a Jesse system drive, the first partition starts at block 2048
(1 MB = 2**20 bytes):

2017-03-08 21:30:04 root@jesse ~
# parted /dev/sda u s p
Model: ATA SAMSUNG SSD UM41 (scsi)
Disk /dev/sda: 31277232s
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:

Number  Start     End        Size       Type     File system  Flags
  1      2048s     976895s    974848s    primary  ext4         boot
  2      976896s   1953791s   976896s    primary
  3      1953792s  28125183s  26171392s  primary

There is content in the first 101 blocks (1 MBR plus 100 other):

2017-03-08 21:30:06 root@jesse ~
# dd if=/dev/sda count=2048 2>/dev/null | hexdump -C | tail
...

What is in blocks 1-101?

Was that disk ever used for anything besides Jessie, not new or wiped first?

Run strings on it or view in a sector editor and you'll probably see grub somewhere, if it's a typical Linux installation that puts Grub in the MBR instead of on a primary partition with its boot flag set, along with generic code in the MBR.

Occasionally some of those sectors are used for RAID.
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