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From: heo@cslsun10.sogang.ac.kr (Heo Sung Gwan)
Message-Id: <9607191338.AA05500@cslsun10.sogang.ac.kr>
Subject: RE: RE:About buffer cache
To: freebsd-fs@FreeBSD.ORG
Date: Fri, 19 Jul 1996 22:38:44 +0900 (KST)
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I think that UNIX file system with buffer cache is not proper to support
multimedia files(e.g mpeg files) becasue buffer cache is based on locality 
of referece(i.e. the recently referened block have high probabiliey to be
referenced again). But multimedia files are accessed sequentially and 
therefore caching of the referenced block is not suitable and the block of
mpeg file referenced by a process has low probability to be accessed by
the other processes. So I think a FIFO buffer per each open file and
the read-ahead to each FIFO buffer are good choice for multimedia file
retrieval. In fact the many filesystems for multimedia adopted this approach(
e.g. UC Berkeley CMFS).

And there are two possible approaches:
1. Modification of buffer cache to FIFO buffers dynamically allocated.
2. User-level process that manages that FIFO buffers that access files 
 through raw disk without buffer cache.
 

Thanks for your resposes.

Heo Sung-Gwan
---
E-mail : heo@cslsun10.sogang.ac.kr