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Re: SPARSE files considered harmful - please revert

Pierre A. Humblet wrote:
> On Mon, May 19, 2003 at 07:54:19PM +0100, Max Bowsher wrote:
>> John Vincent wrote:
>>> I looked up sparse files on MSDN and found the following link:
>>> The most interesting thing is that a sparse file is only sparse if the
>> zeros
>>> in the file are written with a special operation. I strongly suspect
>>> the patch to support sparse files introduced in cygwin is incorrect (or
>>> least incomplete)
>> Areas that are simply seeked over, and never written to, should be sparse
>> well.
> Not only they "should be", they are.
>> Anyway:
>> Based on the posted numbers, global use of sparse files is a bad idea.
>> we conditionalize sparse files on a $CYGWIN option? (Or something else, I
>> don't mind, but the important thing is that it should not be on by
> Why not make in on by default *when it can help*, i.e. when the write()
> leaves holes?

Does anyone know of any programs which write non-sparse files, but not
contiguously? If there are none, then this approach should be fine.

In any case, the $CYGWIN approach could be a valid temporary measure until
someone writes the heuristic code.


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