Upgrades and image manifests

[C. Scott Ananian]

Please read Ivan's update proposal.  He addresses many of the
peripheral issues that have arisen, re user notification, etc.

At this point, as far as I'm concerned, the only open question is how
we get a filesystem image onto the laptop once we know which one to
get.  Ivan suggests rsync; I refined that somewhat with a
directory-at-a-time rsync using manifests; someone else (Mike?)
proposed bittorrent, and previously I proposed a bespoke solution
using binary diffs and multicast.

Alex's work is interesting, but we need to see benchmarks if we're not
going to make a decision based on just fiat and personality.  I've
posted up/download bandwidth for upgrades between 464-465 and 465-466.
 Following up on Mike's suggestion, I've also patched bittorrent to
allow using it for upgrades: the net bandwidth usage is something like
30MB, because it does not use block compression.  I can post more
detailed comparisons if people are interested.  Please perform the
equivalent benchmarks on the updatinator, before we continue this
discussion.
 --scott

-- 
                         ( http://cscott.net/ )