Technology

Taming spam with spamassassin and evolution

Saturday, November 18th, 2006

I’ve found the anti-spam support on Linux to be pretty poor overall. Considering how common this problem is and how ingenious OSS guys usually are, I’m a bit surprised.

I am trying to use Evolution with SpamAssassin, and finding horrible slowness and bugs in the bayes_* databases to be the norm.

If you are attempting this setup, I recommend the following hacks:

1. Do not use bayesian autolearning in spam assassin, as this is a broken way to update your spam filters.
2. Instead, create a JUNK and HAM directory in Evolution, and move your junk mails and ham mails there.
3. If you have already tagged mails as Junk using Evo’s “Mark as Junk” feature, you need to hack these mails out of that folder and move them into a regular Evolution folder. “Mark as Junk” is really not moving mail anywhere, but just “tagging” it, and then the Junk folder is like a vfolder which searches for all mail tagged as junk. This is cool, but sucks if you want to run sa-learn on your mbox in order to train spamassassin. The way to get around it is to create a mail filter in Evo which says: “if mail is marked as junk, then mark it as not junk AND move it it to folder named JUNK.” Then you apply the filter to your Junk directory and Evo will copy them out. (Note: if you try to merely “copy” the mail messages to another folder, they will simply not move — again, Junk is a “tag” in evo, not a location).
4. Now from the shell, go to .evolution/mail/local and find your mbox for your mail. You can use sa-learn –spam –progress –mbox to learn it as a spam, and change –spam to –ham for ham.

This is much better than using the built-in Evo stuff. Do this every few weeks until you don’t have to anymore.

Great tool for LaTeX users

Tuesday, September 12th, 2006

Check it out. It’s called rubber, written in Python.

Mark Zuckerberg: Luckiest Man Alive

Sunday, April 30th, 2006

Sak and I were recently discussing how upset (read: envious, depressed about our own lives) we were about The Facebook seeking $2 billion.

The main reason we’re depressed is because, though both Sak and I like the Facebook and are users, we can’t help noticing one thing:

It’s not that complicated to build a website like that.

In fact, it’s downright easy. If I weren’t so busy with computer science classes, I probably could have threw something like it together myself.

Now, we know that business opportunities don’t have to be complicated to make money. They just have to be Right, that is in the Right place, with the Right look, taking advantage of the Right fad, etc.

But doesn’t it seem to you that a straightforward PHP/MySQL application just isn’t worth $2 billion? I mean, that’s $2,000 million. That’s $2,000,000,000.

Yet, I can’t say I’m entirely unhappy about it. Mark Zuckerberg, here’s to you, man. You’re my age, and you did exactly what I wish I had done. Built some crappy website, and made out like a bandit with sacks of cash. Kudos. You’re honestly my fucking hero.

The Flight of Computer Science majors

Sunday, April 30th, 2006

I read this response to an article at eWeek on Bill Gates’ views about Computer Science research, graduates, spending, and company strategies.

I think it’s pretty clear that despite the disagreements I have with Mr. Gates over a subject known as “business ethics” (if such a subject truly exists!), he does seem to be a genuinely patriotic guy who loves technology. I mean, what good is it for more Americans to get into CS, if other countries are diving in and filling whatever knowledge gap may exist? Can’t Bill just hire those workers, and what’s more, for less money per hour?

Well, I think Mr. Gates really wants innovation in computer software to remain “America’s Great Industry.”

I was very intrigued by this response to the article:

Everyone knows that Open Source is taking over the software development industry. And according to the Open Source philosophy; developers should be enslaved, source code should be free. No, no, that’s not politically correct, let me try again. Developers should give their work away because code needs to be free (as in speech) and the needs of the code is more important than the needs of the people who create it. Well, that doesn’t sound quite right either but in any case, it doesn’t really matter to me because my kids won’t be studying computer science.

This is a very interesting post. True, it will be seen as a troll by some, since open source philosophy definitely doesn’t say anything about programmer enslavement. But his point is real and felt in the industry. That is, if you aren’t selling software, how are software developers to make money from it?

I think the response to this was best-articulated by Eric Raymond, when he pointed out that of programmers, only about 1-2% make their cash from off-the-shelf software sales. Instead, most make their money from “in-house” or “custom” software solutions. In other words, the majority of developers aren’t working on the Adobe Photoshop team, they’re working on Acme Inc.’s payroll or issue tracking system.

I kind of love this sort of propaganda, though. Because it is all good news for me.

When I first decided to do CS, I considered the possible effect of outsourcing and other factors on my employment possibilities. I thought, what if there are no jobs when I get out of college? But I stuck with it.

Well, it turns out, everyone had a hunch similar to mine, but they were more wooed by it than I was. So everyone fled CS. And now I’m the only one left. (An exaggeration, but you get what I mean — my computer science classes are nearly empty, whereas they were packed during registration only a few years ago).

It turns out, firms are hiring more than ever before. Why? Because the dotcom bubble is over, and green-eyed imposters are getting flushed out of the industry. But the demand is still there. Software is pervasive. Everyone needs software development done. There simply isn’t anything under the sun that can’t benefit from a little software developer finesse.

You can’t have all this work done in India and China because, it turns out, people want software developers to work with customers (big surprise). They want applications which meet their sensibilities, and they want them changes when the environment changes.

I liked that Mr. Gates said the #1 thing he’s looking for is project management IT types. Funny, it’s the #1 thing I’m looking for, too. Software developers are a dime a dozen. Find me a software developer who doesn’t get nervous when you ask him a tough question, or ask him to write, in plain English, a high-level overview of the system you’re asking him to create, and you’ve got yourself someone who’s valuable.

Changing the tools you use

Wednesday, April 26th, 2006

Mark Shuttleworth has written a nice little blog post about the tools we learn through life and how we discard old tools and learn new ones.

I personally find this to be very true in my life.

When I was in high school, I prided myself (from the point of view of “tools”) as knowing graphic design (Photoshop/Illustrator), web development, and print/page layout. Handy tools to know for (1) making money and (2) working on a high school newspaper. The only real programming languages I knew back then were Actionscript (for Flash), JavaScript, and (eegads) Perl. Then I got to college and armed myself with algorithms, data structures, and systems, and started picking up Java and C on my own. Now I consider myself well-versed in those, and this past summer learned Python and used that on a lot of different projects. Then this semester I got interested in C++ and used that a lot. Nowadays, when I look at problems, I look at them in terms of my tools. Text parsing problem? Wow, Python’s re (regular expressions) module could handle that pretty easily. Big engineering project? Wow, using templates and OO features in C++ may lead to a nice design. Database-driven web application? Well, Java/JSP may fit you nicely. (I know, I know, what am I doing not knowing Ruby on Rails!)

I think Mark’s onto something. Changing toolsets often is definitely useful. Even though I couldn’t write full programs for you in Perl nowadays, what I do know about it (its limitations, capabilities) is definitely good enough to see when it may be the best choice for the job.

As for academic tools — very true. A lot of techniques I learned in e.g. Discrete Math, Linear Algebra were in one ear and out the other. Alas, I think the main point is to learn them once and then be able to Wikipedia them later, when needed 😉

That said, stuff I learned in my algorithms and data structures and operating systems courses have stayed with me. I think some of that stuff is just essential.

Calculus Made Easy

Tuesday, April 4th, 2006

I am taking “remedial” Calculus II alongside Numerical Computing this semester. My Calc course is “remedial” in that I haven’t seen any Math over the reals for about 4 years (took Discrete Math and Linear Algebra, which both focus on integers) and this semester I am overloading on real numbers (and even complex numbers) just when I had forgotten they even existed 🙂

That said, after spending some time in the humanities (where writing quality is high) and much time in Computer Science (where literacy is defined as being able to read code), coming back to traditional math textbooks has been quite a culture shock. They are so horribly written, it really blows my mind.

So, in response to my horrible Calculus II textbook (published at NYU only for NYU classes, this book features minimal explanation and the maximum amount of notation), I have been using it only for the homework problems and using instead James Stewart’s excellent book, Calculus: Early Transcendentals for rigorous proofs of concepts (because Stewart really does present them nicely), and the lighter but infinitely more illuminating Calculus Made Easy, by Silvanus Thompson.

A somewhat controversial book, Calculus Made Easy chooses to skip the notation-laden explanations of Calculus concepts provided by typical textbooks, and opts instead of a clear, textual elucidation of core concepts in the context of their applications. The philosophy of the book is well-described by this excerpt from the Epilogue.

I think this is wonderful writing, however damning it may be:

It may be confidently assumed that when this tractate Calculus Made Easy falls into the hands of the professional mathematicians, they will (if not too lazy) rise up as one man, and damn it as being a thoroughly bad book. Of that there can be, from their point of view, no possible manner of doubt whatever. It commits several most grievous and deplorable errors.

First, it shows how ridiculously easy most of the operations of the calculus really are.

Secondly, it gives away so many trade secrets. By showing you that what one fool can do, other fools can do also, it lets you see that these mathematical swells, who pride themselves on having mastered such an awfully difficult subject as the calculus, have no such great reason to be puffed up. They like you to think how terribly difficult it is, and don’t want that superstition to be rudely dissipated.

Thirdly, among the dreadful things they will say about “So Easy” is this: that there is an utter failure on the part of the author to demonstrate with rigid and satisfactory completeness the validity of sundry methods which he has presented in simple fashion, and has even dared to use in solving problems! But why should he not? You don’t forbid the use of a watch to every person who does not know how to make one? You don’t object to the musician playing on a violin that he has not himself constructed. You don’t teach the rules of syntax to children until they have already become fluent in the use of speech. It would be equally absurd to require general rigid demonstrations to be expounded to beginners of the calculus.

One thing will the professed mathematicians say about this thoroughly bad and vicious book: that the reason why it is so easy is because the author has left out all the things that are really difficult. And the ghastly fact about this accusation is that — it is true! That is, indeed, why the book has been written — written for the legion of innocents who have hitherto been deterred from acquiring elements of the calculus by the stupid way in which its teaching is almost always presented.

I should note that my Calculus professor is actually quite good, and provides very nice explanations of complex topics, usually beginning with an elucidation of the general idea, and then going on to the formalities. But our assigned textbook is not nearly as clear, and many professors I’ve had in the past have lived entirely inside their constructed notational apparatus.

This reminds me of an old joke I heard awhile back:

A math professor begins his lecture by writing on the blackboard. He only pauses for brief moments of notational explanation, but continues writing and writing, one symbol after the other, for thirty minutes on end. He fills up six blackboards full of derivation, algebraic manipulation, and what have you. At the end, he smiles and draws the open box, indicating the completion of the proof. “Is that clear?” the professor asks. Blank stares all around.

At that point, the professor stops himself. “Oh, no, I believe I’ve made a mistake.” He then looks at the six boards of writing, and begins pointing at certain sections while nodding his head, clearly doing calculations internally. He then paces back and forth across the front of the classroom, with his head bent down and his fist to his chin. For five full minutes, he paces and nods, thinking about the proof just presented.

Then he stops pacing, looks at the students, and says, “Ah, yes, yes. It’s clear.”

Here’s an interesting read, by the way. Came as especially relevant to me, as I “rediscover” math for math’s sake.

Using C++ instead of GObject/C

Tuesday, April 4th, 2006

There’s a great post on why to use C++ instead of GObject/C over at BMP CodeBlog, the blog for developers of beep media player (my preferred MP3 player on Linux). I have to agree with most of what the author says. Using GObject/C is quite cumbersome, I’m almost surprised so many GTK+ developers do it. Especially considering the fact that C++ doesn’t incur overhead unless it has to, nicely expressed here:

The ultimate feature is that all of these are optional. We incur no overhead when we do not use a language feature (with the exception of… exceptions). In fact, cxx_conversion is currently in perfectly valid C++ and uses none of the features or C++ libraries mentioned above yet. The C++ language follows the philosophy of ‘pay for you use’ (better rephrased as ‘don’t pay for what you don’t use’). As it is right now, cxx_conversion is no less (or more) CPU or memory efficient than its C original.

GTKMM keeps getting more and more mature, so now that I’m finally learning C++ properly, I think moving over to GTKMM will be quite nice for a future project that needs a cross-platform UI.

Depressed

Thursday, March 30th, 2006

I just wrote a ~1000 word e-mail in a web-based mail client. When I clicked “send” it told me my session had timed out.

And then the e-mail was gone.

This is why I _hate_ web applications. I am so depressed.

Bad Eye Candy

Thursday, March 23rd, 2006

I recently installed X.Org 7 with Exa, Composite and the famed xcompmgr on my Linux desktop. This didn’t enable any fancy special effects for my lowly built-in via video chipset. However, it did finally do away with “rip and tear” on my desktop. That is, when I drag a window over another one, it just smoothly glides across. When I switch workspace, it’s instant — I don’t see as much “widget redrawing.”

More and more advances are going to inevitably lead to Linux “eye candy.” Here’s a great post on Slashdot regarding good versus bad eye candy.

Here’s a great example: pull-down menus in Mac OS X vs the same in Windows XP. On the Mac, pulldowns appear instantly, and fade away once something is selected; this is correct behaviour, as you asked for a menu – there should be no delay. Fading away is fine because the selection has been made, and you have moved on. In XP, the menus fade up, and vanish instantly – totally backwards. That is bad eye candy.

You know, I never thought about that, but I always turned off menu fading on Windows XP because I could “feel” the delay, even on my Nvidia card on my desktop. I never realized how much more sense it would make to display the menu instantly, and fade it away upon selection.

I hope this conservative approach is taken by Linux devs as they implement eye candy. Functional and beautiful, please.

Apple and Google: Can We Just Get Over Ourselves?

Sunday, March 19th, 2006

So, this is a personal gripe of mine.

In the last, oh, two years or so, it has become increasingly cool to be hip to technology, and, more importantly perhaps, to engage in rampant punditry on the cultural effects of two companies in particular: Google and Apple.

In my school newspaper, Washington Square News, you will find the Opinions editor writing nearly-weekly columns on technology topics. But, what you’ll find, is that Google and Apple get more mentions then basically any other technology company out there. iPods, apparently, changed our culture in shattering ways, because now, instead of people talking to each other on the subway, they listen to their music collection. And web search and web e-mail (which existed before Google, and will exist in various new forms from now onward) is apparently so darn cool when the logo is rainbow colored, but not when its name rhymes with a parting phrase in Spanish.

Don’t get me wrong: if I consider myself a technology afficionado, then Google and Apple technologies are pretty highly rated, in my book. But can we just get over this obsession? I am speaking mainly to that strange cloud known as “the technology press,” but even to all these new technocratic snobs who spend all day talking about their Flikr albums, podcasts and “Web 2.0” calendaring.

Listen, I’ve been around a long time, and others have been along longer. Can we recognize computer products for what they have become? Commodotized fads, just like basically all other products. Technology makes a statement. Some people use GMail and iPods. These people are cool. Other people, like me, prefer no MP3 player, because I think what’s said in New York City is much more valuable than listening to my music.

And guess what? I still have my e-mail collection on a real, rich client, because I think the one I use is more powerful than Gmail will ever be.

Frankly, if you’re going to comment on culture, take a step outside of the Google/Apple obsession. Talk about things that matter. You’re obsessing over the moves of multi-billion dollar publicly traded companies. Companies that have to make a profit, and come up with a bottom line. Your obsession with them only exists because they want it to exist, because their marketers are smart cookies, and you are their pawns.

Just realize that there are lots of important things to talk about, and web-based e-mail and MP3 players just doesn’t make any reasonable list.

Can I also do what a lot of these technology pundits do, and snag up my own law? Here it is, Andrew’s Law: if you aren’t a coder or engineer, you can’t waste all your time commenting on software or technology products. There, that law being in effect, 90% of the web’s blogs should crawl to a dead halt.