Messages in this thread | | | Date | Sat, 20 Mar 1999 16:33:46 +0100 | From | Manfred Spraul <> | Subject | Re: Possible optimization in ext2_file_write() |
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"Stephen C. Tweedie" wrote: > > Hi, > > On Thu, 18 Mar 1999 23:46:57 +0530 (IST), V Ganesh > <ganesh@vxindia.veritas.com> said: > > > it looks like whenever we write a partial block which > > doesn't exist in the buffer cache, ext2_file_write() (and > > possibly the write functions of other filesystems) directly > > reads that block from the block device without checking if > > it is present in the page cache. > > Correct...
I don't know what you are exactly talking about, but there is another problem except speed: Most modern harddisks remap bad sectors, so sometimes you can't read a sector, but if you write the sector is remapped.
I.e. if you "create a new file, write 400 bytes, close the file, sync", then the data sector should not be read.
Our current Windows 95 & Windows NT file system drivers read the data sector, and that has caused problems (older ZIP disks, SyQuest, my own damnaged harddisk?-I don't remember the details).
Regards, Manfred
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