disk devices speed is ugly

Adam Vande More amvandemore at gmail.com
Wed Feb 15 06:27:21 UTC 2012

On Tue, Feb 14, 2012 at 10:50 PM, Scott Long <scottl at samsco.org> wrote:

> Any filesystem that uses bread/bwrite/cluster_read are already using the
> "generic caching subsystem" that you propose.  This includes UDF, CD9660,
> MSDOS, NTFS, XFS, ReiserFS, EXT2FS, and HPFS, i.e. every local storage
> filesystem in the tree except for ZFS.  Not all of them implement
> VOP_GETPAGES/VOP_PUTPAGES, but those are just optimizations for the vnode
> pager, not requirements for using buffer-cache services on block devices.
>  As Kostik pointed out in a parallel email, the only thing that was removed
> from FreeBSD was the userland interface to cached devices via /dev nodes.

Does this mean the Architecture Handbook page is wrong?:


Adam Vande More

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