People doing lots of network IO in threaded programs have historicallyhad a problem: waiting for both network IO and for IPC from threads atthe same time.

Generally you want to wait for network IO using select() or poll() ; trying to use lots of threads, each doing one blocking IOoperation, is usually catastrophic to your performance. But both ofthese only wait on file descriptors, and inter-thread communication inlibraries is almost always implemented with mutexes, semaphores,queues, and so on,

Once again I'll lead with Hotmail's spam numbers, because theycontinue to be bad:

• one email accepted (probably spam).
• 218 messages rejected because they came from non-Hotmail emailaddresses.
• 111 messages sent to our spamtraps.
• 30 messages refused because their sender addresses had already hitour spamtraps.
• 5 messages refused due to their origin IP address (all for being inthe SBL).

Now, on to the general numbers.

This week we received 17,2

Today's illustrative example is about the odd things that can happenif you rename a nameserver without making sure that you tell thepeople delegating zones to you.

There are four nameservers for utoronto.ca : ns1, ns2, bay.cs, andns1.tpc.int (following local practice, I'm dropping the .utoronto.ca bit a lot). Three of those four (everything except ns1) are alsosecondaries for all campus subdomains, including the domain jpint.utoronto