Ira Abramov wrote:
Quoting [EMAIL PROTECTED], from the post of Sat, 30 Nov:
On 29-Nov-2002 David Bergman wrote:indeed, you could have sent a link instead of the full text.
Here's a problem that *sounded* impossible ... I almost regret posting<snip snip snip - most of the story>
the story to a wide audience, because it makes a great tale over drinks
Hear hear.
a lot, or not a lot?there are several points in this story that make it unbelievable in my book. first, that 3ms delay is a lot in early 1990s standards,
Early 1990s means that almost only universities are on the Internet. This makes the net itself more managable.
Hmm, not for server processes, no.second that sendmail as a user process, manages it's own TCP connection timeout when that's a kernel thing. I'm no great programmer, but I think creating a TCP connection is a blocked call and the timeout is fixed in the kernel.
If a server program (a real one, not the kind you write as homework) used blocking calls, it'd require a process/thread for each TCP connection it created. HUGE overhead. What you actually do is use non-blocking calls. They look just like the blocking ones, only you use an ioctl to set the file descriptor to non-blocking, and then use 'select' to find out who is ready for sending, or has information been recevied. When you call select, you use a timeout. Specifically, you don't want to let idle connections hang around for too long, or someone can seriously DoS you.
And how much variance are you experencing today in connection setup times? And this WAS 10 years ago, when a lot less users were on the net (hence -less variance).furthermosre, it assumes all internet links go in straight lines and are equaly wide and equaly congested and that the backbone is indeed that clean.
No, they won't. They will claim that the ELECTRONS don't travel at the speed of light, but that is mostly irelevant to this discussion. The speed of electricity is not far from the speed of light, IIRC.a physicist, ignoring the processing time of cisco microcontrollers and the delay of repeating packets from one side of a switch to the other, and then from ether to WAN and through a modem, would STILL argue that electricity doesn't travel at the speed of light either.
and there are a few other problems.
Do tell.
in short, only a cute suburban legend :)
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