[messaging] Group messaging consistency under resource constraints

[Andy Isaacson]

On Mon, Oct 06, 2014 at 11:07:13PM +0100, Ximin Luo wrote:
> If one doesn't care about consistency of history, it's fine to just
> display messages immediately as they arrive. If one does care about
> it, then you can't. Or at least, I believe not - and nobody has
> proposed a system that does so.

That's a false dichotomy.  Systems frequently display messages as they
arrive, sometimes with an indication of missing history and sometimes
without; and systems frequently insert messages in the history when they
arrive, generally with some indication that this has happened.

And then there's the IRC model where messages just get displayed as they
arrive, and the user can deal with any lossage.

Systems that do variations on this include

LINE
Hipchat
Slack

As it turns out, very few people anymore are using thermal paper
consoles http://www.columbia.edu/cu/computinghistory/la36.html and
UIs can go back and correct history when we learn more detail.

-andy