[mosh-devel] carpal tunnel, measuring latency, and how to disable prediction testing

[Frederik Eaton]

Dear Mosh Developers,

Thank you for a great product. I have thought about the need for
something like this for years, and was happy when I discovered 'mosh'
(a bit late I know).

Your mailing list is not indexed by Google, but I downloaded the
archives and found there seems to be no mention of 'carpal tunnel
syndrome' or 'tendonitis'. I wanted to say that the reason I think a
product like mosh is so valuable, is that according to my own self
observation, typing over high-latency connections causes tendonitis. I
wonder that no one else has made this connection, perhaps it is my own
imagination. (I guess the hypothetical mechanism would be that my
brain sends a "work faster" signal whenever a nerve seems to be
working slowly, according to the delayed visual feedback, causing some
kind of damage to healthy nerves)

In any case, whether for health or "minimum annoyance" reasons, I have
an interest in eliminating latency as much as possible. I don't care
if someone sees part of all of my password, or if control sequences
briefly show up on my editor screen. What I want is for immediate
visual confirmation when one of my fingers pressed a key. The man page
says "The predictive model must prove itself anew on each row of the
terminal and after each control character, so mosh avoids echoing
passwords or non-echoing editor commands." Is there an easy way to
turn this feature off in the source code? Is it a bad idea, for some
reason I haven't anticipated?

My other (related) question is how to measure the actual latency. I
can imagine that someone may have patched xterm to log input and
output characters with sufficiently fine-grained timestamps, so that
the latency of ssh, mosh, screen, etc. could be calculated, as the
user presses random keys. I saw a couple things on your github issue
tracker which look like people are measuring these values. I'm curious
how to measure them myself. My initial trial of mosh (on an Arch
Linux, 800 MHz "Intel(R) Atom(TM) CPU N270" (32-bit)) seems to show a
slightly higher latency than simply typing on a local editor, and I'm
curious to know if this is real.

Thank you again for your dedication and incredibly useful software
contribution, and also for reading my questions.

Please Cc on replies as I'm not subscribed. Thanks,

Frederick Eaton