(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

I've written about interfaces before, orat least what I mean by the term (and how it relates to inheritance ). To summarize, 'interfaces' are a way offormally expressing 'is-a' relationships; when you say that a class or atype implements the String interface, you mean that it is a string.

One of the things that jogged my mind about the whole issue was Go , which has things that it calls 'interfaces' (okay,technically they're called interface

Shortly after I wrote my first ipsCA entry , Igot a comment on the entry recommending a specific other SSL vendor.At first this didn't strike me as unusual; it was the kind of helpfulnote that might be left by one of my readers (or just someone who sawmy blog entry on Planet Sysadmin ). ButI have a hair trigger with spam, one that not infrequently makes meunreasonably suspicious, so I ran the poster's IP address through areverse DNS lookup just to make myself

Some bits on various aspects of the ipsCA root certificate failure .

First, I've seen comments that the new ipsCA CA rootcertificate should be included in the next update ofFirefox. However, I've now found the Mozilla bug about this (via JeffBallard ), and it makesit seem very unlikely that the root certificate is going to be includedin the near future (especially as ipsCA apparently had problems evenbefore this). Interested people can watch Mozilla's CA:Schedule wikipage .

(

Here is a corollary on how push technology breeds spam : even if you have carefully built a pull based systemthat is thus insulated from spam, you need to carefully take a freshlook at it to see if you have any features that do (implicit) pushactions that could be exploited by clever spammers. You'll probablyhave some push features (because they're useful for your users), inwhich case you need a plan for dealing with spam through them.

To be clear here, by '

I've seen a number of people saying that universities who took advantageof ipsCA 's offer of free SSL certificates foreducational institutions are now getting their money's worth, and thatit clearly would have been better to pay a real SSL CA vendor for realcertificates. Would that it were so simple.

The real attraction of the free ipsCA certificates here (and likely atother universities) was not that they saved you $40 US or so. Their realattraction was that you could get them without

Here's something that's important to remember when you're talkingabout vendor support periods (eg, how long a vendor will support an OSrelease): real world support periods are always shorter than what thevendor gives you.

This isn't because the vendor is lying to you or is going to shorten thetime. Instead it is because you can never really use the full supportperiod; you'll never deploy a new version immediately after the vendorreleases it, and you'll almost

This is not exactly news to anyone, but I feel like writing it downanyways: Solaris is not open source, and this matters in practice.

You might well ask, 'but what about OpenSolaris?'

As a sysadmin, the two open source freedoms that I really care about are the freedom to inspect the actualcode you are running and the freedom to fix the actual code that youare running . OpenSolaris does not deliver either of those freedoms,as the OpenSolaris codebase is not the same as the Solaris codebase