Mail Archives: cygwin/2003/05/20/12:37:31
Christopher Faylor wrote:
> On Mon, May 19, 2003 at 07:27:06PM -0400, Bill C. Riemers wrote:
>
>>>I think you need to read the documentation a little more closely. Either that
>>>or provide references to the parts of the documentation that says that
>>>normal RW operations would fragment a sparse file.
>>
>>It is rather obvious. Let say you have three blocks worth of data, and
>>is written into a file with a physical block followed by a sparse block
>>followed by a physical block. No disk space is reserved for the sparse
>>block. Why should it be, as it would defeat the whole purpose of using
>>sparse files? So physically on disk you have two consecutive physical
>>blocks. What then happens if you open the file in RW mode, seek to the
>>sparse block and write some data?
>
>
> 1) You are assuming behavior that isn't documented. I can imagine that
> the first block could occupy, say 16 blocks and depending on the size of
> the hole, there could be no fragmentation.
A agree that he is making an assumption, but he is probably right. Even
if 16 blocks are reserved for adding intermediate blocks, you would
still end up with out-of-order blocks in the file; which isn't as bad as
real fragmentation, but isn't as good as all blocks in order.
> 3) What no one seems to be mentioning is that we are trying to emulate
> UNIX behavior here. If the above is an issue for Windows then it could
> also be an issue for UNIX.
> cgf
And it is.
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