What About An External Multi-Touch Trackpad For a Mac

I used to be a big fan of ergonomic keyboards (and I still am). But I am an even bigger fan of the multi-touch trackpad. I have even extended it by using MultiClutch (I know the link looks funny, but that’s the page title, I promise). MultiClutch allows you to extend the swiping and pinching of fingers to extend to other applications and key combinations (both locally and globally). This means that it is so much a part of my daily productivity that I have had to make due without an ergonomic keyboard.

If someone knows about an external multi-touch trackpad (either wireless or USB) that supports 1,2,3 and 4 finger multi-touch, please let me know. And if one doesn’t exist, please let Apple know :). Ultimately what I would like my “at home” setup to be is a wireless ergonomic keyboard along with a wireless ergonomic multi-touch trackpad.

I’d like to hear everyone’s thoughts on this.

Posted in Mac. Tags: , . 14 Comments »

HOWTO Recreate /dev/null

If something happens that requires you to recreate /dev/null on your *nix system. Don’t fret, it’s easy. The most recent issue I had was that a Capistrano recipe inadvertently clobbered /dev/null. The file looked like this:

[root@web1 ~]# ls -l /dev/null
-rw-r--r-- 1 capistrano engineering 0 May 26 04:02 /dev/null

Thankfully to bring it back to its original state, just run the following commands:

[root@web1 ~]# rm /dev/null
rm: remove regular empty file `/dev/null'? yes
[root@web1 ~]# mknod /dev/null c 1 3
[root@web1 ~]# chmod 666 /dev/null
[root@web1 ~]# ls -l /dev/null
crw-rw-rw- 1 root root 1, 3 May 26 15:09 /dev/null

Take note of the following things:

  • It is not a joke that the mode of /dev/null needs to be 666. It should be user, group, and world read and write.
  • The user and group ownership here is root.
  • There is no size in the ls like you see in the top one. All you should see are the major (1) and minor (3) device numbers (separated by a comma) prior to the date.

Why Idea People Should Twitter

Let me start off by explaining what I mean by an “Idea Person.” To me, an idea person is someone who just has a knack for thinking of things that would make the world a better place (or at least make things easier for some people). They don’t necessarily need to be a scientist on the order of Albert Einstein, but they should be people who are constantly thinking. Something like, “Wouldn’t it be great if in men’s rooms in bars, there was padding above the urinals so men wouldn’t hit their heads while relieving themselves.”. It’s just an idea.

Quite often, people don’t get those ideas out fast enough and they lose them. It even could be because their minds move so quickly that they forget to jot it down. Enter age of instant gratification. If you have an idea, Tweet it. Of course you could blog about it, but then people may only get it when they read your feed or whenever they get around to checking your blog. But with Twitter, its an almost instantaneous media connection. All it takes is one person who is highly followed in Twitter to retweet your idea(s) and you instantly have high visibility.

Why does this matter? Well I’m glad you asked. Because an idea person may not always have the want or even the means to implement the ideas, but with the connections and viral dispersion of information that Twitter provides, someone somewhere will have the means and may share your desire. Someone may even be able to point out the fact that the project or idea already exists (or is in production). Who knows you might just end up finding a new business partner on Twitter if you follow the right people and the right people follow you.

More Efficient SPAM Fighting with Amavisd-logwatch

This is the first in a multipart series on better SPAM fighting through log parsing. I have found that better Systems Administration can usually be achieved through proper log handling and analysis. In fact, I will use the data from one of the secondary mail servers in my personal mail setup in order to demonstrate this data analysis. I will do this by going through the report generated by amavisd-logwatch piece meal until complete.

I previously posted about a program that parses your amavisd-new SPAM log file called amavisd-logwatch. Now I am going to give you some tutorials of how to make efficient use of the results. I am assuming that you have access your SpamAssassin scoring config files. I am also assuming that you have access to the log parsing results. I have mine sent via email daily.

One item I would like to mention is that when making changes to SPAMAssassin, ensure that you make them in a separate file from the default configuration files. I use /etc/spamassassin/local_tests.cf. I strongly recommend this setup as this makes it easier to segment your configuration files by type when your rule sets and modifications start to get larger and larger.

Section: Bayes Probability
First things first, skip the majority of the summary sections and go right down to the section on Bayes probability:

Bayes Probability Information

Bayes Probability Information

You’ll notice that of the 14,627 times that the Bayesian filter was run on messages, that it came up with BAYES_99 11,825 of those times (or 80.85%) . You’ll also notice that all the subsequent BAYES_XX probability tests were extremely low (2nd and 3rd place being 5.4% and 4.5% respectively).

Conclusion: Assuming that you are relatively happy with your current level of SPAM filtering, that would mean that your Bayes filter is doing fairly well (in general). You may not need to tweak it. If you are feeling frisky though, to tweak the impact that the BAYES_99. To change this, open up your local_test.cf and add the line:

score BAYES_99 (1.25)

This increases your BAYES_99 score by 1.25 points from its base. It doesn’t have to be 1.25 points, start small to see what you are comfortable with and slowly work your way up. Be careful as too high a jump will cause false positives which makes for angry users.

Section: SPAM Score Frequency
The SPAM score frequency refers to how often a piece of email scores within a given range.

SPAM Score Frequency

SPAM Score Frequency

Conclusion: Taking note of the fact that nearly 60% of the emails scored a 30 or higher, and assuming again that you are comfortable with your SPAM filter, you can adjust the SPAM kill score threshold in amavisd-new accordingly. I trust my SPAM filter, but I have written many rules and made many tweaks to it. So I have set my SPAM kill threshold low enough (15.8 to be exact). As you can see, this is pretty close to the middle of the set of numbers (also known as the median). This eliminates the delivery of the vast majority of the obvious SPAM.

Stay tuned for the next part in the series where we will tweak the individual scores based on the results report.