sneakernet calculation

[brian carroll]

On Wed, Sep 25, 2013 at 3:21 PM, Eugen Leitl wrote:

For very high latency you could just use a global sneakernet.
> http://what-if.xkcd.com/31/ has some numbers.
>

quoted from that site:

"Cisco estimates that total internet traffic currently averages 167
terabits per second. FedEx has a fleet of 654 aircraft with a lift capacity
of 26.5 million pounds daily. A solid-state laptop drive weighs about 78
grams and can hold up to a terabyte.

"That means FedEx is capable of transferring 150 exabytes of data per day,
or 14 petabits per second—almost a hundred times the current throughput of
the internet."

i imagine most with mathematical instinct would think something
'real-world' is missing in this approximation, in that you could not
realistically use-up all FedEx resources for such a data sharing project
without likely taking down the system or being denied access- and thus
existing traffic and congestion are not included in this ideal naive model.

what would actually occur if you tried to use all FedEx shipping resources
on a single day, and then after considering that, doing so repeatedly day
after day. not only is I/O data transfer omitted (time needed to
access/store/exchange data between platforms), though also hardware
failures which, perhaps i am wrong- packet technology succeeds in
transferring via multiple attempts and thus the 'internet traffic' of 167
terabits could potentially includes delivery failures and successful
resends, and routing around congestion- whereas it is completely
unrealistic to assume you could decide to ship such material and use up all
"network" resources of FedEx without considering its tolerances for
additional bandwidth to cover this parallelism, and also limits of local
delivery or to various locations in an overnight scenario-- so delays would
likely be involved, and if any data on laptop drives were to fail it would
seemingly require reshipment to compare to the internet data transmission
approach. or not.

it is not to lose grasp of the notion, only to consider it in its depth,
and knowing what may feasibly and more actually occur in such a scenario
could provide a more accurate understanding of the limits of analogies
without corresponding matched dimensions. such that maybe it would not be
as efficient or as easy or even possible, as believed. though the simple
mathematical comparison makes it appear so. and most comparisons of this
nature often have similar 'modeling errors' where approximations function
in an ideological realm as a result, though likewise makes for interesting
considerations in considering where the gap is between what is said and
what exists as a situation.
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