[TUHS] Mach for i386 / Mt Xinu or other

[jason-tuhs at shalott.net]

> I got to thinking about the file system sync vs. order argument as a 
> result of this interesting discussion.
> [...]
> What we discovered, when we added the Linux cluster, was that building 
> power was really terrible. We had not realized it with the freebsd 
> cluster because it tended to cleanly recover from unplanned nasty power 
> cycles. But the Linux cluster tended to always have a small number of 
> nodes that did not get through fsck.

Soft updates was available in 1998.  Were you running that?

Surprised it hasn't come up already in this discussion; I've been waiting 
for someone to mention it.

http://www.mckusick.com/softdep/

There was some licensing issue with it in the early days: it was freely 
available and free to use, but McKusick wanted a chance to try to sell it 
to a commercial unix vendor as well.  But he ended up BSD-licensing it a 
couple years later.

The original README from the FreeBSD source tree:
https://svnweb.freebsd.org/base/release/3.0.0/contrib/sys/softupdates/README?revision=42952&view=co


Anyway, it solved the on-disk consistency problem and boosted performance 
as well.  I enabled it on all my systems.


  -Jason