Graham

This is probably only of interest to perhaps three of you, but what the heck.

I discovered today that EventMachine, a very commonly used Ruby library, has a completely broken popen implementation. Specifically, it doesn't ever call waitpid unless you are

• Running on Linux and have selected the epoll option
• or the process closes all of its input sockets.

In practice this means that if your subprocess spawns a background process and exits, EventMachine will not notify you of that process exiting until the subprocess dies too.

Lost a couple hours to this. It is in no way atypical of either EventMachine or Ruby, sadly.

Fun fact: the checksum size computed for tar archives is 16 bytes long. This is not documented anywhere.

I've been finally (after around two years) getting around to developing some of my backlog of film, while waiting impatiently for my blackout cloth to arrive so that I can actually have a darkroom. It is amusing in some ways to contrast my two main hobbies these days; long obsolete Nikon lenses that won't work on most current bodies are still $300 a pop which will buy you damn near any hand tool you could want in woodworking. Mostly I'm finding a strange budding desire to go shooting with my 4x5 camera (a bit of a production because I can't remember which film holders, if any, have any film in them!).

Incidentally, Rachel, I have some photos from your wedding now :)

It's weird working on something as part of a team, or especially as something someone else wants done but where the spec is a little bit different every day. They're good about it, it's not the usual spec hell stuff, but it can be very disorienting to come in and discover someone has e.g. decided your internal structures should really look like Y rather than X.

Similarly strange is the insistence folks have about me contacting e.g. the Subversion developers when I am having trouble using their ludicrously poorly specified library bindings. I eventually made myself understood by saying that "ok, if I haven't resolved the problem by this evening I'll email them but usually butting my head against stone walls takes less time than talking to people". Which is, I think, true for me with email. Less so with in-person type stuff but I have much less hesitation about going up to a coworker and saying "so, uh, WTF. Seriously."

My iPad arrived today, when I was home sick due to weird intestinal problems (the less spoken of, the better). Man, there is no surer way to make an iPhone look tiny than to compare it to Big Brother here.

I think it'll do what I bought it to do admirably, that being reading papers for work and the like. Not sold on it as a web browser quite yet, but perhaps. The landscape keyboard is so close to being almost useful at it hurts, but the portrait is … I dunno, less useful for actual input? I can make it work but it isn't exactly flawless.

Minor annoyance is that there is as far as I can tell no iPad native LiveJournal apps. I could run the iPhone versions (which operate fine) in reduced screen mode but that is profoundly unsatisfying in a way that is difficult to coherently express. I dunno. We'll see, for sure. OS 4 for the iPad can't get here soon enough.

Summary at a friend's page. As he puts it Livejournal is secretly, and deliberately, changing certain outbound links that you post.

GRAHAM:

Phone? Phone? Wake up, I want to play games.

PHONE:

*iz ded*

GRAHAM:

Bollocks. Out of batteries. *unpacks computer* Power? Power? Where are you?

POWER:

*iz hiding*

GRAHAM:

Oh, there you are.

POWER:

*panicks and cowers in a narrow space smaller than Graham's arm*

GRAHAM:

Fuck. *scrapes up arm getting power plug in* *spends hour sorting out which power adapter belongs to which appliance* *is finally ready to power Phone* Ah, finally. Now then, to plug phone in. …. Phone? Where the devil did you get with no batteries?!

PHONE:

*iz hiding in book in bathroom for no adequately explored reason*

In happier news I am nearly moved in to the new house. Unpacking is something else but already my garage is 8x more useful than the old workshop was. Now I just need to find antifatigue mats…

First, the joke: ( joke )

And then some food for thought: ( on learning )

I've come across a rather interesting CS problem during work that I thought I'd throw out there. The problem is this: given a finite lattice (L, ⊑) (our problem has a lattice that is also distributive, so you may presume that) and a node x in that lattice, efficiently compute the set S ⊆ L = { y ∈ L : x ⊏ y ∧ ∄ z x ⊏ z ⊏ y }. This is well defined, and starting from ⊥ it is possible to walk the entire lattice easily (which is why we care). If you precompute the lattice you can do this trivially. Is it possible to do so without considering every node in the lattice?

Failing that, can you give me an efficient algorithm for computing the structure of the lattice from a set L and a partial order ⊑ ?

I do not yet understand how to be both crazy and compassionate.
BEING CRAZY IS NOISY | More Intelligent Life

Interesting article in some ways.