Web lists-archives.com

Re: DD bs=4M option on USB mem-stick creates false format




Hi,

i adopted the idea of a dry run for educational purposes.
It demonstrates in detail what make_isombr_part would do to the
storage device.

With debian-8.7.1-i386-xfce-CD-1.iso on /dev/sdc:
-------------------------------------------------------------------------
$ ./make_isombr_part /dev/sdc auto 83 dry_run
Note: Storage capacity of '/dev/sdc' : 3915776 blocks

Dry run suppressed writing of 16 bytes to byte address 478 :
             478 : 00 ff ff ff 83 ff ff ff 00 38 14 00 00 88 27 00
Note: Omitted MBR partition slot 3, type 0x83, start 1325056, blocks 2590720

Dry run suppressed writing of 32 bytes to byte address 0 :
               0 : 33 ed 90 90 90 90 90 90 90 90 90 90 90 90 90 90
              16 : 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
Note: Spared APM signature

Dry run suppressed writing of 8 bytes to byte address 512 :
             512 : 77 61 73 20 67 70 74 20
Note: Spared GPT signature at block 1

Dry run suppressed writing of 8 bytes to byte address 678428160 :
       678428160 : 77 61 73 20 67 70 74 20
Note: Spared GPT signature at block 1325055

$
-------------------------------------------------------------------------
In contrast to a wet run:
-------------------------------------------------------------------------
$ ./make_isombr_part /dev/sdc auto 83
Note: Storage capacity of '/dev/sdc' : 3915776 blocks
Note: Wrote MBR partition slot 3, type 0x83, start 1325056, blocks 2590720
Note: Wrote APM signature
Note: Wrote GPT signature at block 1
Note: Wrote GPT signature at block 1325055
$
-------------------------------------------------------------------------

The downloadable files have been updated.

Source:
  http://scdbackup.webframe.org/make_isombr_part.c
  MD5 7f922c2dda85814a5a0210c2ad4e6cfb 
  Compile by
    cc -g -Wall -o make_isombr_part make_isombr_part.c

amd64 executable binary:
  http://scdbackup.webframe.org/make_isombr_part
  MD5 56de878a525c4e642fa7b2fac14dea82


Have a nice day :)

Thomas