Re: [MLUG] Linux time command -- "kernel mode" and "user mode"

["Matt Klaric" <EMAIL:PROTECTED>]

On 11/3/06, Stephen Montgomery-Smith <EMAIL:PROTECTED> wrote:

The caching you talk of does take place, but actually it takes place in
just about any decent file-io implementation.  For example, 'printf' in
C has caching.  It only writes the info to the files once it has
collected about 128 bytes to write out.  The only function that has the
possibility to write a byte at a time is the core function 'write' (or
printf if you first apply the function 'setbuf' which allows you to tune
the caching behavior).

The behavior of printf (and other higher level output functions) is actually called buffering.  Caching describes the process of  holding recently and/or frequently accessed information for fast access in case it needs to be retrieved for additional accesses.  Buffering is the processes which was described--holding data in a buffer until the buffer is full or it is manually flushed.  While both of these allow for more efficient I/O, there is a distinction.  

--matt
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