Subject: Re: Soft update code integrated into the main tree
To: None <current-users@netbsd.org>
From: None <seebs@plethora.net>
List: current-users
Date: 11/15/1999 15:47:52
In message <Pine.GSO.3.96.991115163922.939A-100000@notes.erc.clarkson.edu>, Tod
d Cohen writes:
>Ok, I've seen this mentioned many times, and I just can't figure out what
>soft update is.. can someone please enlighten me? :)

Some day when I'm not a lazy putz I've been planning to do a nice article on
this for daemon news.

To summarize, soft updates is a way of enhancing the disk buffering code, with
two major effects:

1.  You can get the speed you would have expected from a completely async
mount, with the data reliability you'd expect from our normal half-sync mount,
or better.
2.  You can get better speed than that, really, because soft updates are
sufficiently clever that you can
	create a directory
	create files in that directory
	modify the files
	remove the files
	remove the directory
and have *NO DISK ACTIVITY AT ALL*.

Very clever.

-s