Mutexes and Semaphores

Cross-posting from my RTI blog:

This post doesn’t contain any new information or clever opinions. It simply points out a few articles published elsewhere that this humble author suspects his readers will find relevant. (Members of the Embedded group on LinkedIn may have seen some of these articles already, but they have relevance to any multi-threaded system, embedded or not.)

Many developers suffer from confusion with respect to the differences between mutexes and semaphores. Michael Barr of Netrino provides solid information in his article Mutexes and Semaphores Demystified. My summary: mutexes protect shared resources by enforcing mutual exclusion; semaphores should be used for signaling across tasks.

Verdict on "The Public Option": Revision

I wrote earlier about my feelings about a so-called "public option" health insurance plan. What I predicted at that time was that a public plan would subsume existing federally financed health plans (Medicare, Medicaid, the VA health plan, government employee insurance, etc.) and as a result would become very much larger than its private competitors. The result, I believed (and still believe), would be the ultimate collapse of those competitors and therefore a hobbling of our health system:

• The facade of an employer-based, competitive system would provide less access than a true single-payer system
• ...without permitting the emergence and flourishing of a secondary value-added market, such as exists in the UK and elsewhere
• ...and without any of the benefits that might come from a transparent, competitive, open market.

It would be better, if such were the case case, to embrace one extreme or the other -- single payer or a much freer market -- rather than to be stuck with a suboptimal hybrid of the two.

But our president laid out a very different vision of a public option today. The public plan he described violated my first assumptions: it would not automatically subsume the plans offered to government employees, it would not be available to everyone, and apparently even the uninsured would not be enrolled automatically; they would choose among plans like the rest of us. In that case, I have no objection to it. As the president pointed out, public universities coexist with private, and others have pointed out that the government-chartered Postal Service coexists with fully private parcel carriers.

... Although I have to wonder: if the plan is deliberately crippled to keep people out of it, what's the point? Is this political cover for diehards who swore they wouldn't vote for a bill without a public option plus a wink to conservatives that the "option" will be a token only?

Judicial Activism

Tomorrow, the U.S. Supreme Court will re-hear a case it heard back in March, Citizens United v. Federal Election Commission. Intelligent, principled people can disagree on the particulars of the case; this post isn't about those particulars. It's about the judicial process.

Re-hearing a recent case is very unusual, and it often indicates that the court is strongly considering overturning a previous precedent.

Conservatives are famous for preaching about the dangers of "judicial activism" -- overstepping the role of a jurist and attempting to create new law -- and often criticize liberals for supposedly practicing it. Yet if the supposedly-conservative court rules in favor of Citizens United in this case, it will reverse a century of precedent and overturn federal law.

This is not unlike the recent case DC v. Heller, in which the court overturned both law and long-standing precedent to change the gun laws in the District of Columbia.

I might also ask those conservatives to stand up who disagree with the ruling in Brown v. Board of Education, which overturned decades of precedent in school segregation and the laws of many states.

All of this gives the lie to the "judicial activism" soapbox speeches. I'm not saying that there's no line between the role of a jurist and that of a legislator. But it's a fat grey line, not a thin red one. Everyone has his or her own idea about what the Constitution ought to say. Ninety percent of the time, when someone says "She's a judicial activist," what he really means is, "She disagreed with me." And of course, if the justice does agree with us, we praise her discernment in seeing through to the true, authentic meaning of the beloved text.

So let's just admit it, and let's have a conversation about where that line is and where it should be. But enough soapbox.

Socialist Madman Corrupts Children with Message of Personal Responsibility

September 8, 2009 5:00 pm.

As expected, megalomaniacal anti-American Communist agitator Barack Hussein Obama made yet another attempt to brainwash our country's children today with a subversive message: work hard and stay in school. "We need every single one of you to develop your talents, skills and intellect," said Obama, clearly indicating his desire for his would-be underage proletarian sycophants to rise up -- against the nation's capitalist leaders, its churches, and ultimately each towheaded child's own two-parent nuclear family -- in murderous revolution.

"If you want a good job you have to have a good education," responded one new disciple as his values system slipped away.

With his address, Obama joins discredited Socialists Ronald Reagan and George H. W. Bush, whose attempts to undermine American democracy were crushed in previous decades beneath waves of populist rage.

Source Code Hosting for Those of All Sexual Orientations

I was catching up on back issues of the web comic xkcd the other day and I had to chuckle at this one:

(For those readers who don't know xkcd: there is a very nearly bijective mapping between between being in the target audience for this comic and thinking it is completely hilarious. Sorry, English majors: it may not be your bag. But no hard feelings.)

Maybe not funny enough to click "share" in Google Reader, but definitely cute.

This evening, I decided -- totally independently -- to get a bit smarter about git, and on a whim I googled "GitHub for Lesbians." Lo and behold, I came upon this project immediately: http://github.com/lesbians. It took those lesbians a full three days from the posting of the strip to create the project, but still: I salute you, industrious lesbians.

On Fire: Update -- Now with Graphs! (TM)

Size of the Station Fire

My Prairie Home Nemesis

Many of those who know me well know that I listen to a lot of public radio. As in, hours. Every day. I find television impossible when I want to multitask, commercial music radio so unpredictable and polluted by commercials as to be utterly not-worth-it, and commercial talk radio so filled with obnoxious glib people with stupid nicknames as to inspire me to criminal acts of violence against them. So the vicious (or virtuous?) cycle continues: the more frustrated I become with other media, the more I turn to my old standby, and the more I do that, ....

It is therefore in this context that I feel the need to get something off my chest:

I have almost no interest, whatsoever, in A Prairie Home Companion.

I have nothing against the man, but honestly: if Garrison Keillor were to be hit by a bus tomorrow, I'm confident that I would traverse the Stages of Grief within about a minute and a half.

Apparently, I am alone in this feeling. I say this because I swear that 80% of all weekend afternoon and evening airtime is dedicated to That Show. I switched on the radio last weekend three different times looking for something, anything, informative and/or interesting and/or humorous to listen to. I got the same episode of "Prairie Home" three times. I just hit the show for the second time today. It's like I'm in a horror movie, running and running, but every time I turn around, Guy Noir a singing cowboy a slice of rhubarb pie the slow-moving guy with the meat hook is right there behind me. Where am I to turn?

It's not just my station either. The last city I lived in, same thing. In fact, try this: go to google.com and type "prai" -- it auto-completes to "prairie home companion" already! How can it be that in all the web there is nothing beginning with those letters that is more popular than this show? Is there no widely esteemed praise band out there? Are there no fans of the prairie dog to be found? I have just learned that there is an entire people out there called the Prai; apparently, nothing that any of them has ever done can rival the cultural juggernaut that is A Prairie Home Companion.

In Progress at OMG: Extensible and Dynamic Types

Cross-posting from my RTI blog:

One of the really powerful things about DDS is that it brings to distributed systems the same kind of type safety that you’ll find in local applications. In addition to reducing errors, this deep knowledge of data types can improve performance and resource usage by reducing the number of data copies in the system and easing integration with other field- and type-aware technologies, including relational databases and even Microsoft Excel.

Read the whole post here.