On Mon, Aug 18, 2003 at 11:13:48PM -0400, Jeff Macdonald wrote: > Hi, > I am trying to understand how one uses raw disk i/o in Linux. I
If you're not a filesystem engineer, you probably just really don't want to do this. This is the level at which the filesystem reads and writes data -- it is a raw byte stream. If you write data at this level, you will destroy your filesystem. > understand that the i/o skips the kernel buffer. Well, IIRC, unlike most other Unix implementations, Linux disk I/O is /always/ block I/O (i.e. buffered by the kernel) unless you apply patches to the kernel. However, if what you're trying to do is avoid a layer of buffers to increase performance, have a look at memory-mapped I/O. See the man page for mmap(2), and/or a good book on programming on Unix systems. I'd suggest W. Richard Stevens' "Advanced Programming in the Unix Environment" for starters. -- Derek D. Martin http://www.pizzashack.org/ GPG Key ID: 0xDFBEAD02 -=-=-=-=- This message is posted from an invalid address. Replying to it will result in undeliverable mail. Sorry for the inconvenience. Thank the spammers.
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