I wrote a tiny DOS program called resize that simply did a seek out to a (user specified) point, and wrote zero bytes. One (documented) side effect of DOS was that writing zero bytes would truncate the file at that point. But it also worked to extend the file to that point without writing any actual data. The net effect was that it adjusted the FAT table, and none of the data. It was used frequently for file recovery, unformatting, etc. And it was very fast.

Unfortunately, although the program still ran under NT (which includes Win 2000, XP, ...), the security system insists on zeroing all the intervening sectors, which takes much time, obviously.

Still, if the data is not important (make the first sector unique, and the rest zeroes), this would probably be the fastest way to get all those files created. Just write the file name in the first sector (since we'[ll separately make sure the filename is unique), and then seek out to a billion, and write one more byte. I won't assume that writing zero bytes would work for Unix.

andrea wrote:
On 31 Mar, 12:14, "venutaurus...@gmail.com" <venutaurus...@gmail.com>
wrote:
That time is reasonable. The randomness should be in such a way that
MD5 checksum of no two files should be the same.The main reason for
having such a huge data is for doing stress testing of our product.


In randomness is not necessary (as I understood) you can just create
one single file and then modify one bit of it iteratively for 1000
times.
It's enough to make the checksum change.

Is there a way to create a file to big withouth actually writing
anything in python (just give me the garbage that is already on the
disk)?

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