Archive for September, 2006

Simscan and SpamAssassin

3300 spam messages rejected on mail RCPT in the last six days. 550 per day.

That is 550 messages a day I don’t have to bother checking for false positives or manually deleting. I should have added SpamAssassian to Simscan much earlier.

You can see elsewhere on this site of how I installed Simscan with Qmail. Adding spam checking at the mail border with Simscan is was simply a matter of apt-getting SpamAssassian, recompiling Simscan by changing from

./configure --enable-workdir=/var/spool/simscan/ --enable-received=y


./configure --enable-workdir=/var/spool/simscan/ --enable-received=y --enable-attach --enable-spam --enable-spam-hits=5

and building a good copus of spam messages. Combined with a centralised bayes token file:

$ cat /etc/spamassassin/
bayes_path        /var/spool/spamassassin/bayes
bayes_file_mode   0666

At the moment I’m added spam messages manually with sa-learn, but I expect I will setup a cron job in due course which checks an IMAP folder. Plus with this method the problem with false positives is much less, as senders of non-spam messages will received a definite non-delivery message. They are more likely to catch this than for me to notice them amongst 550 pieces of spam.

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24-bit RDP under Windows XP

From Think Thin:

Open up the Registry Editor (Start -> Run -> regedit) and navigate to the following key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp

Change color depth to 4.

Reboot Windows XP to have the change take effect.

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Tunesafe – A discussion of using S3 as part of a business

Very well written and indepth business case analysis of the use of S3.

Outsiders do not realise how deeply technological development, like scientific research, is shaped and driven by emotion. If you have ever looked at an iPod and wished that you needed one, you will have had an inkling of it. The reason that half of us are in computing at all is that we see computers as things that we can make beautiful things out of: and S3 and EC2 arouse the same emotion.

Some people have criticized S3 and EC2 for being bony, but that is the point of them. You cannot go wrong if you have good, strong bones to build on. If the foundation is right, things just go on getting better. A woman with good bones is six times as beautiful at 60 as she is at 20.

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Rentable Computing, part ii

I’ve been looking a little closer at EC2 and it seems like a very clean idea, giving simple building blocks to provide rentable computing. There are a couple howtos that are worth reading:

  1. Exploring Amazon EC2
  2. How To Create an Ubuntu Image

EC2 is using virtualisation system, providing the equivalent of a 1.7Ghz Xeon, 1.75GB of RAM and 160GB disk. It would be interesting to know exactly what platform they are using,
I suspect some version of Xen. With a decent generic para-virtualised kernel (as provided by EC2) you can support pretty much any Linux distribution.

With a tool like this I start wondering about the potential uses. Reduce the system by at 25%, install pre-configured asterisk, and you can start selling virtual PBX to groups of people on demand. I wonder if it might be possible to run a full Ubuntu desktop with NX. Suspend and resume your desktop on demand as you travel around the world.

I can see how this project is provide great value to Amazon internally as well. EC2 and S3 combined provided them with a scalable mechanism for providing an internal cost mechanism for managing their sizable investment in infrastructure. They “out-source” the cost of infrastructure internally, fixing the cost of computing. This gives a deterministic method for both production and development groups to plan and scale new projects. With a consistent metric to measure
the cost of computing, developers can instead focus on producing content.

On the other side of the coin it also sends pricing signals to competitors, by dictating the cost of computing and managing the ecosphere it runs within they give themselves a lift ahead of others.

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Firefox is going to kick Internet Explorers Ass

Extensions like this adaptiveblue:

With the blueorganizer Firefox extension, your browser becomes smarter. It helps you personalize your web experience based on what you already like. It harnesses your information to help you discover relevant new information and save time.

and S3Fox Organizer for Amazon:

This firefox extension(browser plugin) provides an user friendly interface for Amazon’s S3 (Simple Storage Service) . Its interface is very much similar to the FTP interface that lists local folders in the left panel and S3 buckets/files/folders in the right panel. Files/folders can be moved from the local computer to Amazon’s storage space and vice versa. Follow the pre-requisites & steps described below to start using S3Fox Organizer.

are just not possible or likely to happen with IE. The Firefox ecosphere of extensions makes the Internet a whole lot more interesting.

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Economics in Six Minutes

Everyone should spend a few moments and read Economics in Six Minutes:

Economics is the science of utility, which includes people’s preferences and the satisfaction and importance they subjectively derive from goods. Desires are unlimited, but people get less extra value from more and more units of the same good.

A good distillation of the key concepts.

From The Angry Economist.

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Check out this very cool photo software under development Microsoft Labs: photosynth.

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Comments on Opteron 2000 vs Xeon 5100

Here is a few useful comments by Nick Anderson on the xen-users mailing list.

It depends on your application. Dont forget to look at residual cost of owning a Xeon 5100. I believe that it requires fully buffered dimms each pulling 9 to 14 Watt compared to non-fully buffered dimms for the new Opterons that support DDR2 which I think draw 2-3 watts per dimm. Plus even though the Xeon requires less power for the chip itself they dont take into account the fact that the Opterons have an on die memory controller. The Xeons have a separate memory controller which I believe draws another
2 Watts.

Kind of went on a tangent there … but really it does depend on the type of applications you are running. I seem to remember the Xeons whop up on the Opterons in single threaded applications, however I think the reverse is true when you start using threaded applications.

Obviously the figures from the review I mentioned yesterday aren’t so clear cut. However, now Intel are producing solid tech, there is no longer the bad taste from their hiding behind a market position and market power. It will be interesting to see what the Anandtechs and other tech-head reviewers say when they get this equipment. Better choice can only be good.

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I was cruising though an iscsi mailing list when I discovered this post.

Moka5 seems to be building some very similar to what I visualised in my post about Virtual Appliances. The are building what they call LivePCs for the deployment of software running on VMWare based VPUs. One of the cool bits of tech they have is the ability to boot a system before it has completed streaming to your VPU:

This player loads optimized virtual machines on-demand, and allows the VM to be executed before the entire image is downloaded. For example, a 1.3GB VM can boot up to the desktop after downloading just 60 MB (1/20th the amount of data). This took 10 minutes over a cable modem, instead of 200 minutes.

Sign up for their beta, check their library of existing appliances and see how it works.

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Xenoppix=Xen+Knoppix with Xen3.0.2+KNOPPIX5.0.1. It can book Knoppix on HVM, and they have some screenshots of doing this on an iMac. Very clever.

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