Feisty live CD killed HD

Liam Proven lproven at gmail.com
Tue Sep 4 14:41:04 UTC 2007

On 04/09/07, m_epling <m_epling at comcast.net> wrote:
>  thats crazy ...you must be a windows FUD person . no way a live cd can
> destroy a hard rive even during a format

Just a small point of order. A software operation *can* render a hard
disk permanently useless.

An example:

Errors in track 0 cannot be mapped out in software, as track 0 is
where the bad-block error map lives.

Imagine a hard disk that has an unnoticed bad block in the partition
table. Partitions can be read and written OK, but if something
attempts to change the table, then the block can't be written and
suddenly the disk fails.

The partitioning operation itself does not itself damage the disk; it
merely exposes existing damage. However, to the user, repartitioning
killed the drive.

On modern EIDE drives, the drive itself does transparent bad-block
remapping below the level that the OS can see. However, this is not
infallible. Once all the reserve blocks have been used, errors - bad
blocks - become visible to the OS. So the scenario I describe would
need the disk to have already exhausted its hot-spare-block capacity.
That does happen; I have seen it several times.

Liam Proven • Profile: http://www.linkedin.com/in/liamproven
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