Subject: filesystems, disks, and caching To: None <tech-
kern@NetBSD.ORG> From: Erik E. Fair <> List: tech-kern Date:
06/11/1998 17:32:12 We may need to rethink caching a bit. Right
now, the two levels of it that we've been discussing are:  1. in
the main RAM of the of the system, some number of NetBSD kernel
buffers holding disk blocks are kept around, to avoid hitting
the disk for that information more than once in some period of
time, subject to available memory restrictions.  2. in the HDA
electronics of various disk drives.  We currently have some per-
filesystem options for being more aggressive about caching, and
how often we force bits to oxide for reliability, e.g.  It
strikes me that we need a SCSI (and possible EIDE) tool for
playing with the options available in the HDA electronics, and
some documentation that lays out the options and risks for the
person configuring a NetBSD system. There is a program I recall,
called "scsitool" (or somesuch) from U of Toronto, that might be
a good place to start.