On Wed, 17 Dec 1997, Hubert Feyrer wrote:
>
> Can anyone make a comment about this?
> Is it good, will we get it, do we want it, ...?
> 
>  - Hubert

Soft updates are a real win!  It speeds up disk writes by reordering the
metadata and data writes so as to maintain consistency while minimizing the
number of disk accesses.  Basically, it avoids unecessary writes...

Looking in the copyright included in the OpenBSD snapshot of the softupdates
code, we find both a reference to the paper (it's found at:
 http://www.pdos.lcs.mit.edu/~ganger/papers/CSE-TR-254-95/) and the person to
contact about getting permission to use his code:


/*
 * Copyright 1997 Marshall Kirk McKusick. All Rights Reserved.
 *
 * The soft updates code is derived from the appendix of a University
 * of Michigan technical report (Gregory R. Ganger and Yale N. Patt,
 * "Soft Updates: A Solution to the Metadata Update Problem in File
 * Systems", CSE-TR-254-95, August 1995).
 *
 * The following are the copyrights and redistribution conditions that
 * apply to this copy of the soft update software. For a license
 * to use, redistribute or sell the soft update software under
 * conditions other than those described here, please contact the
 * author at one of the following addresses:
 *
 *      Marshall Kirk McKusick          mckusick@mckusick.com
 *      1614 Oxford Street              +1-510-843-9542
 *      Berkeley, CA 94709-1608
 *      USA

...



Someone from Core want to contact Kirk and ask for a copy?  I'll bet that he has
based his work on either BSD4.4 or BSDI's code, so it should be fairly easy to
integrate into NetBSD.

Paul
--
Paul Dokas                                            dokas@cs.umn.edu
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Don Juan Matus:  "an enigma wrapped in mystery wrapped in a tortilla."