You wrote:
> Greetings all,
> I'd like to find out more info about 'deleted' files on our pcs and
> vaxs. For instance, how is a 'deleted' file ultimately deleted?
> What process is involved to truly delete a file from magnetic
> media? We might be looking to purchase some s/w product that could
> 'scrub' our drives, getting rid of 'deleted' files, but I'd like to
> learn more about the process first. Thanks,
> Lou
> Louis T. Chmielewski
> Security Manager/DBA
> Doctor's Associates Inc. (Subway)
> (203) 877-4281 x1128
I don't know the methodology that the VAX uses; however, in the pc world it is a fairly simple process to store and recover files.
The data section is stored in blocks on the disk. The blocks are linked/referenced from a File Allocation Table. Windoze (DOS) maintains two copies of the FAT. A delete is a simple process of changing the first letter of the FAT entry which releases that location for future use.
A disk space is not dymanically re-allocated, it is possible to recover deleted files until that space has been used.
There are a few products that will write a pattern of 1's and 0's several times over the entire disk in an attempt to make it un-readable.
John Stewart
SUPSHIP San Diego
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