On Mon, 16 Jun 2003 Davef1624@aol.com wrote:

> Is the Unified Buffer Cache (ubc) on by default
> now with NetBSD 1.6?

Yes, but that's like asking if the vm system is on by default. It's part
of the system and can't be turned on or off.

> When the UBC is enabled, what is the purpose
> of the original file system buffer cache?
> Is it only used to buffer file meta-data?

Yes.

> (in routines like vflushbuf() I notice a
> call to VOP_PUTPAGES() which flushes
> all VM data cache pages for the file,
> and *then* calls to bwrite() --
> this appears redundant).

Take care,

Bill