5 ms·

Reminded me of “The case of the 500-mile email”: http://www.ibiblio.org/harris/500milemail.html http://www.ibiblio.org/harris/500milemail.html

hmottestad 12y ago
That was a great post and well worth the read.
vacri 12y ago
I was impressed that the users were able to troubleshoot the fault that specifically in the first place.
- tragic 12y ago
  Also, that it's pretty clear that they were only able to do so because they had limited technical knowledge of email: to someone who runs a mail server, the idea of email not getting further than 500 miles is ridiculous and absurd. To someone not used to it, not so much... I'm sure there's a cute name for this specific variety of irony, but I don't know what it is.
  - mtdewcmu 12y ago
    I think it had a little bit to do with the users being statistics professors, too. That might just be the ideal background for writing bug reports.
  - userbinator 12y ago
    to someone who runs a mail server, the idea of email not getting further than 500 miles is ridiculous and absurd Not really, unless that someone doesn't know about the structure of networks. My first two hypotheses after reading the problem description were routing anomalies and timeouts. That other story about the car and vanilla ice cream, on the other hand, is a great example of unintended correlation != causation.
- mseebach 12y ago
  Well, it did involve people with the job title "geostatistician".
lt 12y ago
Or the "Car allergic to vanilla ice cream" tale. http://www.cgl.uwaterloo.ca/~smann/IceCream/humor.html http://www.cgl.uwaterloo.ca/~smann/IceCream/humor.html
- poizan42 12y ago
  Or the "OpenOffice can't print on Tuesdays" bug https://bugs.launchpad.net/ubuntu/+source/cupsys/+bug/255161/comments/28 https://bugs.launchpad.net/ubuntu/+source/cupsys/+bug/255161...
  - jes5199 12y ago
    That one reminds me of the system I worked on years ago that wouldn't accept credit cards that expired in August or September (of any year).
    - T-hawk 12y ago
      I bet it was a Javascript system that tried to interpret month numbers of 08 and 09 as octal because of the leading zero. Am I close?
- bjterry 12y ago
  That's clearly a tale rather than a true event. The guy would have noticed during other extremely short trips that his car wouldn't start afterwards.
mbell 12y ago
Fun article, but I don't completely buy the conclusion. The propagation speed of cat-5, coax and fiber optic cable all fall in the neighborhood of ~60-70% the speed of light in vacuum. Also it's very unlikeliness to have anything resembling a straight line path from the mail server to the destination. If the connections were aborted in a bit over 3ms you would have much shorter range than 500 miles, I'd guess something like 1/4 to 1/2 that distance between the lower propagation speed and indirect path.
- tedunangst 12y ago
  The timeout was unlikely to be 3ms. A 100hz clock would give you a timeout of 10ms. Also, the timeout needs to cover the distance in both directions. Half of 10ms is 5ms, which is just about enough for a 60% of c transmission to go 500 miles.
- frandroid 12y ago
  Read the FAQ, linked at the top.

hmottestad 12y ago

That was a great post and well worth the read.

vacri 12y ago

I was impressed that the users were able to troubleshoot the fault that specifically in the first place.

tragic 12y ago
Also, that it's pretty clear that they were only able to do so because they had limited technical knowledge of email: to someone who runs a mail server, the idea of email not getting further than 500 miles is ridiculous and absurd. To someone not used to it, not so much... I'm sure there's a cute name for this specific variety of irony, but I don't know what it is.
- mtdewcmu 12y ago
  I think it had a little bit to do with the users being statistics professors, too. That might just be the ideal background for writing bug reports.
- userbinator 12y ago
  to someone who runs a mail server, the idea of email not getting further than 500 miles is ridiculous and absurd Not really, unless that someone doesn't know about the structure of networks. My first two hypotheses after reading the problem description were routing anomalies and timeouts. That other story about the car and vanilla ice cream, on the other hand, is a great example of unintended correlation != causation.
mseebach 12y ago
Well, it did involve people with the job title "geostatistician".

lt 12y ago

Or the "Car allergic to vanilla ice cream" tale. http://www.cgl.uwaterloo.ca/~smann/IceCream/humor.html http://www.cgl.uwaterloo.ca/~smann/IceCream/humor.html

poizan42 12y ago
Or the "OpenOffice can't print on Tuesdays" bug https://bugs.launchpad.net/ubuntu/+source/cupsys/+bug/255161/comments/28 https://bugs.launchpad.net/ubuntu/+source/cupsys/+bug/255161...
- jes5199 12y ago
  That one reminds me of the system I worked on years ago that wouldn't accept credit cards that expired in August or September (of any year).
  - T-hawk 12y ago
    I bet it was a Javascript system that tried to interpret month numbers of 08 and 09 as octal because of the leading zero. Am I close?
bjterry 12y ago
That's clearly a tale rather than a true event. The guy would have noticed during other extremely short trips that his car wouldn't start afterwards.

mbell 12y ago

Fun article, but I don't completely buy the conclusion. The propagation speed of cat-5, coax and fiber optic cable all fall in the neighborhood of ~60-70% the speed of light in vacuum. Also it's very unlikeliness to have anything resembling a straight line path from the mail server to the destination. If the connections were aborted in a bit over 3ms you would have much shorter range than 500 miles, I'd guess something like 1/4 to 1/2 that distance between the lower propagation speed and indirect path.

tedunangst 12y ago
The timeout was unlikely to be 3ms. A 100hz clock would give you a timeout of 10ms. Also, the timeout needs to cover the distance in both directions. Half of 10ms is 5ms, which is just about enough for a 60% of c transmission to go 500 miles.
frandroid 12y ago
Read the FAQ, linked at the top.