This is the mail archive of the
mailing list for the Cygwin project.
cygwin-1.3.21-1, problem with sparse file creation as default
- From: "Markus Mauhart" <markus dot mauhart at chello dot at>
- To: cygwin at cygwin dot com
- Date: Thu, 13 Mar 2003 16:09:54 +0100
- Subject: cygwin-1.3.21-1, problem with sparse file creation as default
I have a problem with the following new feature of cygwin-1.3.21-1
> - Create sparse files by default, when possible. (Vaclav Haisman)
Couldnt it be made configurable, or removed ?
1) good old file manager (winfile.exe from NT4 system) does not display
sparse files - so all newly created files (through gcc, or make,
or "cp con 123.txt") are now invisible. (beside browsing, I didnt test real
file operations like move/copy a folder containing some sparse files)
2) AFAICS its advantages are very sparse ;-) Only when extending
a file's size the sytem (ntfs5+) automatically adds 'sparse' clusters.
Otherwise (even when writing 10G of all zero) not a single sector
is spared. Only programs aware of win32-sparse files profit from this
existing file-attribute when explicitely marking a range as zero,
but IMHO this is a micro-profit: such program can replace the following
if (make_file_sparse(..)) mark_some_range_as_zero(..);
... with ...
if (is_file_sparse(..)) mark_some_range_as_zero(..);
Note, this was assuming the win32 file API. Are there any cygwin/GNU
file API's (except for file creation;-) which when used then automatically
profit from sparse files ?
3) OTOH my guess is that it introduces more or less unnecessary resource
consumption (CPU and/or disk) ... one benchmark could be building
gcc and messuring time and disk consumption, but last time I built gcc
was in 2001; maybe Vaclav Haisman could benchmark the pros and cons
of this new feature. (also defragmenting a volume with 10.000 of such
newly created 'pseudo-sparse' files might pay a price)
Anyway, thanks for your attention,
Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
Bug reporting: http://cygwin.com/bugs.html