October has come, and with it, another Ubuntu release (12.10). I finally gave in and reinstalled my system as 64-bit land (so long 32-bit), mostly because graphics were broken on my upgraded system. As far as I could tell, lightdm was dying immediately after starting up, and I couldn’t tell where in my copious configuration I had messed it up. I also started encrypting my home directory.
- All fstab mount entries now show up in Nautilus. The correct fix appears to be not putting these mounts in
/media, /mnt or /home/, and then they won’t be picked up. - Fonts continue to be an exquisite pain in rxvt-unicode. I had to switch from
URxvt.letterSpace: -1 to URxvt.letterSpace: -2 to keep things working, and the fonts still look inexplicably different. (I haven’t figured out why, but the new world order isn’t a complete eyesore so I’ve given up for now.) There’s also a patch which fixes this problem (hat tip this libxft2 bug bug) but I found that at least for DejaVu the letterSpace hack was equivalent. - When you manually suspend your laptop and close the lid too rapidly, Ubuntu also registers the close laptop event, so when you resume, it will re-suspend! Fortunately, this is pretty harmless; if you press the power-button again, it will resume properly. You can also work around this by turning off resume on close lid in your power settings.
- On resume, the network manager applet no longer accurately reflects what network you are connected to (it thinks you’re connected, but doesn’t know to what, or what signal strength it is). It’s mostly harmless but kind of annoying; if anyone’s figured this one out please let me know!
- Hibernate continues not to work, though I haven’t tried too hard to get it working.
- Firefox was being really slow, so I reset it. And then it was fast again. Holy smoke! Worth a try if you’ve found Firefox to be really slow.
- GHC is now 7.4.2, so you’ll need to rebuild. “When do we get our 7.6 shinies!”
My labmates continue to tease me for not switching to Arch. We’ll see…
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I was wandering through the Gates building when the latest issue of the ACM XRDS, a student written magazine, caught my eye.
“Oh, didn’t I write an article for this issue?” Yes, I had!
The online version is here, though I hear it’s behind a paywall, so I’ve copypasted a draft version of the article below. Fun fact: The first version of this article had a Jeff Dean fact, but we got rid of it because we weren’t sure if everyone knew what Jeff Dean facts were…
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This post is the spiritual predecessor to Flipping Burgers in coBurger King.
What does it mean for something to be dual? A category theorist would say, “It’s the same thing, but with all the arrows flipped around.” This answer seems frustratingly vague, but actually it’s quite precise. The only thing missing is knowing what arrows flip around! If you know the arrows, then you know how to dualize. In this post, I’d like to take a few structures that are well known to Haskellers, describe what the arrows for this structure look like, and then show that when we flip the arrows, we get a dual concept.
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This post is adapted from the talk which Deian Stefan gave for Hails at OSDI 2012.
It is a truth universally acknowledged that any website (e.g. Facebook) is in want of a web platform (e.g. the Facebook API). Web platforms are awesome, because they allow third-party developers to build apps which operate on our personal data.
But web platforms are also scary. After all, they allow third-party developers to build apps which operate on our personal data. For all we know, they could be selling our email addresses to spamlords or snooping on our personal messages. With the ubiquity of third-party applications, it’s nearly trivial to steal personal data. Even if we assumed that all developers had our best interests at heart, we’d still have to worry about developers who don’t understand (or care about) security.
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So you’re half bored to death working on your propositional logic problem set (after all, you know what AND and OR are, being a computer scientist), and suddenly the problem set gives you a real stinker of a question:
Is it true that Γ ⊢ A implies that Γ ⊢ ¬A is false?
and you think, “Double negation, no problem!” and say “Of course!” Which, of course, is wrong: right after you turn it in, you think, “Aw crap, if Γ contains a contradiction, then I can prove both A and ¬A.” And then you wonder, “Well crap, I have no intuition for this shit at all.”
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Jon Howell dreams of a new Internet. In this new Internet, cross-browser compatibility checking is a distant memory and new features can be unilaterally be added to browsers without having to convince the world to upgrade first. The idea which makes this Internet possible is so crazy, it just might work.
What if a web request didn’t just download a web page, but the browser too?
“That’s stupid,” you might say, “No way I’m running random binaries from the Internet!” But you’d be wrong: Howell knows how to do this, and furthermore, how to do so in a way that is safer than the JavaScript your browser regularly receives and executes. The idea is simple: the code you’re executing (be it native, bytecode or text) is not important, rather, it is the system API exposed to the code that determines the safety of the system.
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Caveat emptor: half-baked research ideas ahead.
What is a monad? One answer is that it is a way of sequencing actions in a non-strict language, a way of saying “this should be executed before that.” But another answer is that it is programmable semicolon, a way of implementing custom side-effects when doing computation. These include bread and butter effects like state, control flow and nondeterminism, to more exotic ones such as labeled IO. Such functionality is useful, even if you don’t need monads for sequencing!
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