Moonbase

Baman, Piderman, and Dali

MenTaLguY — 2008-08-30T15:27:00+00:00

For you.

(Both these gems are by Alexander Butera; I hope we get to see more from him in the future!)

The (Not So) Great Desecration

MenTaLguY — 2008-07-28T04:00:26+00:00

I don’t have a whole lot to say about science blogger PZ Myers’ public desecration of an allegedly consecrated host. I think it is fair to take him at his word that he does not seriously entertain the idea that a piece of bread could by divine fiat become the Body of Christ (which brings to mind Christ’s response the first time people started sticking nails in it ). In any case, that much is between him and God, and I generally wouldn’t expect a non-Catholic to have a Catholic perspective on the issue.

What I do hope most people would recognize is the basic immaturity of the act, even from a strictly secular point of view: in such terms, it’s akin to a grade-schooler taking from another child the special sandwich the child’s mother had prepared for him and grinding it into the dust because it was “stupid”. Of an adult academic, such an act would suggest an exceptionally poor standard of public behavior. That Myers’ act was carefully premeditated, and that the intended recipients of the Eucharist place an even higher value on it, that only makes that issue worse.

I realize that Myers had taken it upon himself to act in retaliation for threats made by a few of my co-religionists in an unrelated Florida incident. But if certain people are acting like vindictive children, an adult response does not mean similarly immature behavior, and an adult response most certainly does not mean taking it out on an entire religious group.

Update: Based on the replies I am getting, it seems that there are four issues which I need to clear up.

First, Myers (at least if his own claims are to be believed) didn’t simply obtain a wafer of the same sort of bread which is used in Catholic rites (which, absent any confusion, nobody would really care about), he specifically sought out a wafer that had actually been in the posession of the Church and had been consecrated by a Catholic priest.

Second, there isn’t a legitimate way to remove a consecrated host from the Church’s custody. The Church does not relinquish custody of a host distributed at Mass until it has actually been eaten. To this end, Catholic churches train their staff—ushers, priests, deacons, and extraordinary ministers—to observe and ensure that the consecrated hosts distributed are consumed on the spot as intended (even if, as this incident shows, they are not always adequately vigilant).

Third, even if the removal of the host in this case might have constituted petty theft (or grand theft, if the “buy it now” price on that one eBay auction is indicative of the monetary value of consecrated hosts), I’m deliberately avoiding legal considerations. From a simple, human, secular standpoint, the basic issue is that it’s inappropriate for a mature adult to take an article of extreme sentimental value to its intended recipients and destroy it in public as a deliberate act of spite.

Fourth, the original threats Myers was retaliating against were directed at a kid in Florida, not him personally. Professor Myers read about this in the media like the rest of us, and decided to take it upon himself to strike a blow for … something. (As far as I can tell, his two main accomplishments so far have been to provoke some of the same morons to start sending him threats, and to offend an awful lot of uninvolved Catholics.)

Communist Coercive Methods for Eliciting Individual Compliance

MenTaLguY — 2008-07-02T19:18:37+00:00

I think this article can speak for itself:

The military trainers who came to Guantánamo Bay in December 2002 based an entire interrogation class on a chart showing the effects of “coercive management techniques” for possible use on prisoners, including “sleep deprivation,” “prolonged constraint,” and “exposure.”

What the trainers did not say, and may not have known, was that their chart had been copied verbatim from a 1957 Air Force study of Chinese Communist techniques used during the Korean War to obtain confessions, many of them false, from American prisoners.

...

“What makes this document doubly stunning is that these were techniques to get false confessions,” Levin said. “People say we need intelligence, and we do. But we don’t need false intelligence.”

...

The only change made in the chart presented at Guantánamo was to drop its original title: “Communist Coercive Methods for Eliciting Individual Compliance.”

Grand Central WAGgery

MenTaLguY — 2008-06-19T02:49:01+00:00

Apple’s announcement of their Grand Central technology sounds interesting, but it’s pretty light on details. Here’s my wild guess, based on the intersection of what they’ve hinted at and what I would do if I were in their shoes: my guess is that they’re integrating support for fine-grained scheduling (as in e.g. TBB) into the OS scheduler, which would enable smarter global decisions about things like work balancing and cache warmth.

Think M:N threads with better kernel support, but minus the usual attempt to make the “userspace” portion of the scheduler preemptive. If they’re smart, they’ll also include non-blocking/asynchronous equivalents of standard blocking APIs, though in principle with sufficient kernel support they could also permit tasks to use some blocking operations in more transparent ways.

I guess we’ll see how good my guess was in a year or so.

The Museum of RetroTechnology

MenTaLguY — 2008-06-15T03:04:24+00:00

The Museum of RetroTechnology is a compilation of various “steampunk-type” technologies which were or are in use in the real world.

(Hat Tip: Nathan)

Yes.

MenTaLguY — 2008-06-06T21:33:03+00:00

(On YouTube)

The Rebellion Within

MenTaLguY — 2008-06-06T17:37:45+00:00

The Rebellion Within is a long but really fascinating and somewhat surprising look at the origins and recent development of Jihadist organizations since the 1970s.

(Hat Tip: Tim Bray)

Want to Become a WiiWare Developer?

MenTaLguY — 2008-06-03T18:52:55+00:00

There was a lot of buzz about WiiWare on the message boards when it first came out, as if it were something with a low barrier to entry comparable to, say, Microsoft’s XNA.

It’s not, okay guys? WiiWare is just an alternate distribution channel for Wii games, complimenting pressed discs in stores. Since WiiWare games are necessarily smaller in scope and the distribution mechanism doesn’t involve the same financial commitments as discs, Nintendo will certainly approve titles for WiiWare that wouldn’t be worth their while to approve as a UPC to go on shelves, and perhaps will also be willing to take a little more risk with developers who have less proven experience, but that’s about the extent of the difference to regular Wii development.

That said, if you’re an indie game development company leasing commercial office space, with some published titles under your belt (or at least a wildly popular flash games site), and for some inexplicable reason you managed to get that far without knowing where to look for these things, the Nintendo SDSG has a list of requirements and an application form posted on their website.

I hope that helps clear up any confusion.

A Harley Pedal Stop for Aeolus

MenTaLguY — 2008-06-02T02:39:05+00:00

Harley Davidson supposedly puts a lot of care into the sound of their motorcycle exhaust systems. What if a Harley exhaust system or three were rigged to a pipe organ to supply the nice low notes you can’t normally get?

My brilliant friend Nathan took some time to simulate the result using the Aeolus organ simulator to record a performance of BVW540 (a Bach Toccata and Fugue in F Major) using the “Harley stop”.

The Future of the Omnibus

MenTaLguY — 2008-05-31T23:46:14+00:00

After Andrea O. K. Wright’s wildly popular (popular as in she had to schedule a second session after the first one literally overflowed with people) RailsConf talk it seems like now is a good time to give an update on my plans for the Omnibus Concurrency Library, especially after I’ve neglected it for so long.

At this point, the next version of the library is likely to be a complete rewrite, licensed under an MIT-style license similar to Rubinius’. It will aim to support at least the following Ruby implementations, with others following as time and interest permit:

Ruby 1.8
Ruby 1.9
Rubinus
JRuby

Portability

Presently, only JRuby presents opportunities for improved parallel performance with Omnibus’ thread-centric implementation; under Ruby 1.8, 1.9, and Rubinius, performance will necessarily be equal to or less than single-threaded performance. Why support them at all? There are two main reasons:

The first reason to support green-threaded Ruby implementations is for the sake of portability, allowing the same program that runs under JRuby on a multi-core behemoth from Sun to scale all the way down to a single-CPU machine running Ruby 1.8 with its green threads.

Secondly, concurrent programming abstractions are often convenient ways to structure programs even on single-processor systems. (If they weren’t, nobody would ever bother with Ruby 1.8’s green threads.)

Additionally, the concurrency picture for some of these Ruby implementations is not necessarily bleak in the long-term: Rubinius already permits taking advantage of multiple threads per process in separate VMs. A future version of Rubinius may offer more fine-grained multicore support, and a future version of Omnibus may find ways to exploit things like the existing per-VM multicore support, or even include support for fork-based parallelism for some purposes.

Organization

Rather than Omnibus remaining a monolithic library, I’m also going to be breaking things up in order to enable individual components to be released as separate gems (and hopefully in a more timely fashion):

concurrent – “omnibus” gem which pulls in the others as dependencies
concurrent-actors – Actors for Ruby
concurrent-futures – Futures for Ruby
concurrent-joins – Join calculus for Ruby
concurrent-parallel – Parallel algorithms and parallel extensions to core/stdlib classes (corresponding roughly to TBB parallel algorithms)
concurrent-primitives – Grab-bag of simple primitives like channels
concurrent-selectable – Semaphore and a few other primitives which can be waited on using existing event-based IO libraries, or just IO.select (DONE)
concurrent-sequential – Force strict sequential execution of asynchronous tasks, even in the face of multiple threads or reentrancy. Don’t laugh, it’s useful.
concurrent-tasks – Task-oriented parallelism (similar to TBB tasks)

Major Changes and Incompatibilities

One of the major changes coming is that the library will handle asynchronous tasks (e.g. from futures, or joins) by dispatching them to a TBB-like task scheduler instead of simply spawning a new thread for each task. In most cases this means that the creation of continuation tasks is the preferred alternative to blocking, although there will still be provisions to support blocking tasks. The largest effect of this change will be the elimination of transparent futures from the core library, since they have the effect of causing arbitrary tasks to block, and have consistently been the most difficult feature of the library to implement portably anyway.

There will also be some less drastic, but incompatible, changes to the rest of the existing APIs. In particular, parallel algorithms will take grain sizes rather than a count of threads to spawn, and the actor API will be modified to match the current Rubinius API more closely.

Timeline

Especially since Omnibus is a spare time project for me at the moment, I can’t commit to a timetable for the new release, but at the moment I’m aiming to have the new release out in 2-3 months. Watch this space.

(Incidentally, feel free to contact me if you’re interested in funding some aspect of Omnibus development. I am committed to finishing Omnibus regardless, but obviously paid projects have to take precedence.)