LFCS Question 38

Community Discussion

Written by other learners. Comments can disagree with the marked answer — check the official documentation when in doubt.

• Chose C1

  The command that overwrites the bootloader located on '/dev/sda' without overwriting the partition table or any data following it is 'dd if=/dev/zero of=/dev/sda bs=440 count=1'. The correct answer is Option C. The 'dd' command is a utility for copying data from one location to another. It can be used to overwrite data on a device, such as a hard drive or a bootloader. The 'if' option specifies the input file, and the 'of' option specifies the output file. The 'bs' option specifies the block size, and the 'count' option specifies the number of blocks to copy. In this case, the command will copy a single block of data ('count=1') from '/dev/zero' (a special file that provides an endless stream of zero bits) to '/dev/sda' using a block size of '440' bytes. This will overwrite the bootloader located on '/dev/sda' without overwriting the partition table or any data following it.

• 1

  The other options will overwrite more data on the device, potentially causing data loss or corruption. Option C will overwrite the first 440 bytes of the device, which is the correct block size to overwrite the bootloader without overwriting the partition table or any data following it. Option A will overwrite the entire device, including the partition table and all data. Option B will overwrite the first 512 bytes of the device, potentially causing data loss or corruption. Option D will overwrite the entire device, including the partition table and all data.

• 1

  For example in Windows, “the 4 bytes following the first 440 bytes contain the Windows Unique Disk Signature” -> https://unix.stackexchange.com/questions/254657/mbr-size-is-440-bytes-or-512-bytes#254662