My original writeup under
palimpset (not hardlinked, because it's not spelt like that) was :
A text that has been written over another, whether on paper, stone or whatever (wax?). Like when you write down messages on a phone pad and it comes through to the next sheet. Essentially the hard disk is such a record of past messages and documents.
However, although the comparison with a hard disk interested
wharfinger, I don't know very much about hard-disks. I had heard that 'deleting' a file merely means removing the
pointer (or whatever) to the start of the file. The information is still there, it's just inaccessible. As time goes on, other files are written
on top (as it were) - overlapping and within the old file. If you were to print out the entire
hard-disk, bit by bit, you would find relics of past letters, fragments of code and so on.
The best analogy is the connection of the genome with the hard-disk through the vellum of Rook's write-up, above. In this analogy, files are genes and pointers are promoters. The promoter is the region upstream of the gene that controls its expression, just as the pointer is the control over retrieval of the file. If the promoter is lost through mutation, the gene is 'deleted' and is no longer made into protein. However, it is possible for promoters to be created through mutation (I assume) - and old, forgotten, genes can be brought 'back into service' by the ever resourceful cell.
In the terms of this analogy, hard disk recovery and genome sequencing are equivalent tasks! Both read the palimsest laid down by a historical process of creation and deletion of references to the start of sequences.
Furthermore,
Jongleur says:
What you have said about hard drives is quite true as far as it goes. On many systems, that is exactly what happens. On Windows systems it is (or used to be) even sillier. The first character of the filename was changed to something unprintable, and the space was marked as free. DOS and Windows were then programmed not to show the existence of any filenames starting with that character. Silly but true, and perhaps even more of a palimpsest.