(This is likely obvious, but since I keep working it out again in myhead I'm going to write it down once and for all.)

Suppose that you have a CSP -likeenvironment, with lightweight processes and synchronous communicationchannels with no buffering. Synchronous channels are simple but veryinconvenient for many real-world things, where you need to haveasynchronous channels. Fortunately, you can turn synchronous channelsinto acceptable asynchronous ones as follows.

To send an asynchronous message, you spawn a new process and

In a comment on my entry on software RAID's advantages I was asked what I thought about sofware RAID'slack of battery backup units, as you can get on better RAID controllercards. To answer that, I'm going to start by asking my traditionalquestion: how does having a BBU RAID card improve your systemperformance?

A RAID card with a battery backup unit effectively turns synchronousdisk writes into asynchronous ones, by buffering such writes in itsbattery-backed RAM and immediately telling the host OS