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On Sat, May 24, 2003 at 09:58:13AM +0200, Lapo Luchini wrote: >Rolf Campbell wrote: > >>>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. >> >>And it is. > >e.g. from FreeBSD 4.8's "man mmap": > > WARNING! Extending a file with ftruncate(2), thus cre- > ating a big hole, and then filling the hole by modify- > ing a shared mmap() can lead to severe file fragmenta- > tion. In order to avoid such fragmentation you should > always pre-allocate the file's backing store by > write()ing zero's into the newly extended area prior to > modifying the area via your mmap(). The fragmentation > problem is especially sensitive to MAP_NOSYNC pages, > because pages may be flushed to disk in a totally ran- > dom order. And so, my point is proved. Thanks. The feature stays. cgf -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
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