jlm-blog
~jlm

14-Mar-2014

The thing about sides

Filed under: politics — jlm @ 10:17

Dianne Feinstein, my senator, has been making waves as of late after discovering the CIA had been spying on her congressional staff. The waves are not so much on the merits of the charge, but due to the history of the person making them: Sen. Feinstein has until now been a vociferous booster for the US’s intelligence agencies, and their intelligence-gathering operations, both foreign and domestic. She was, for example, perhaps the Democrat most vocally in favor of granting the phone companies unqualified immunity for participation in bulk wiretapping of their customers. Had that immunity not halted the lawsuits back in 2008, part of the scope of the intelligence community’s bulk domestic spying would have come out in discovery long before Edward Snowden popped up on the radar, and perhaps the CIA, NSA, etc. would not have been so bold these last six years in exceeding their authority under the FISA.

So now Sen. Feinstein has gotten bit, and is indignant that it’s from the very snake she has been feeding and protecting. My surprise is that this is to Feinstein’s surprise! There’s an old saying — just because you’re on their side doesn’t mean they’re on your side. Seems my very honorable senator is rapidly becoming acquainted with the application of that proverb, somehow managing to get into the US Senate without having been!

28-Dec-2013

Happy Christmas from Edward Snowden

Filed under: politics — jlm @ 12:46

A holiday message from our currently most famous fugitive.

And may your new year be private.

16-Dec-2013

Good job, China. Awful job, media.

Filed under: science — jlm @ 11:34

China has pulled off the first Moon landing in 37 years and just deployed a lunar rover. Nice job!

You wouldn’t know it if you just get your news from the L.A. Times or S.F. Chronicle, though. What the hell, news media? This is not newsworthy?!

16-Nov-2013

… and also the wrong things with the wrong people

Filed under: web — jlm @ 18:21

G+ advertises user control over sharing on post complaining of G+ unauthorized oversharing

<SOURCE>

 
"That's what we call Irony!"

23-Dec-2012

Addressing the fragile base class problem

Filed under: programming — jlm @ 21:47

I’ve been thinking about the fragile base class problem lately. (Yes, I know it’s almost Christmas. My mind works mysteriously.) I started thinking by analogy to APIs, which the interface a superclass gives a subclass in fact is, even if it’s not called that. So, the superclass’s API changes, breaking the subclass, just like a regular API’s change can break a client. How do we deal with this with regular APIs? If we are to make a compatibility-breaking change (which introducing any member into a superclass potentially is), we version the API so that a client requesting version 1 semantics gets them while only clients written against the newer semantics will request version 2. We could do the same kind of thing with class inheritance if we mark everything with revision numbers, which we reference when inheriting.

class base@2 {
    void start@1();
    void stop@1();
    void idle@2();
};

class child@1 extends base@1 {
    void idle@1();
    void park@1();
};

Here’s our classic case of a fragile base class. child subclassed base and defined the new method idle(), then later base was extended with its own method idle(). Normally, this would cause a problem — the new stop() implementation might call idle() perhaps, and child’s idle() won’t be written with overriding a then-nonexistent base::idle() in mind. But with these revision markings, we say that child only overrides methods marked as being in revision 1 of base. So, when stop() calls idle(), it gets base::idle, not child::idle, and when park() calls idle(), the call resolution goes the other way.

The problem I see with this though, is that when going to an indirect superclass, it can be unclear which revision that should be.

class grandparent@3 {
    void method@2();
};

class parent@2 extends grandparent@2;

class child@1 extends parent@1 {
    void method@1();
};

Uh-oh. Should child’s method() override grandparent’s? If parent@1 extended grandparent@2, then yes. But if it extended grandparent@1, then no. So do we need to list the parent class revisions of every revision of the child class? I’d hope there’d be a better way. Perhaps we’d be relying on an IDE to handle the revision numbers for us, keeping them updated is just a dumb task, so in that case the IDE could maintain the manifest of parent revisions too.

20-Nov-2012

How not to do automatic updates

Filed under: linux — jlm @ 10:47

Today’s attempt at upgrading packages produced this:

Reading package lists... Error!
E: Encountered a section with no Package: header
E: Problem with MergeList /var/lib/apt/lists/extras.ubuntu.com_ubuntu_dists_precise_main_i18n_Translation-en
E: The package lists or status file could not be parsed or opened.

The contents of that file?

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<HTML>
<HEAD>
   <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">  
   <META HTTP-EQUIV="Pragma" CONTENT="no-cache">
   <META HTTP-EQUIV="refresh" CONTENT="0;url=https://login.wifiportal.co.nz">
   <TITLE>Welcome to FIVO Hotspot, Product of Natcom LTD NZ</TITLE>
</HEAD>
<BODY>

</BODY>
</HTML>

I don’t have unattended upgrades enabled on my Ubuntu laptop. Nevertheless, there’s something which goes around and replaces files in /var/lib/apt with whatever junk it gets from whatever network it happens to be connected to at random times. Can I be the only person who thinks this is a Really Bad Idea?

21-Sep-2012

Pre-desecrated ikons

Filed under: animals — jlm @ 12:10

A distressing report from National Geographic: Elephant poaching for ivory is growing alarmingly, devastating elephant populations, and the demand for elephant ivory is for making holy objects. I don’t understand this at all. How can anything made from the illegal killing of an African elephant for its tusks’ ivory be holy? How is that poaching for making ikons not sacrilege to Christians and Buddhists? How can the buyers worship using an ikon made from such desecration?

19-Sep-2012

Foray into short science fiction

Filed under: misc, science — jlm @ 18:58

“So, what’s the news?”

“Nothing much. The ship with Bob Ritchie and Lori Walton’s bodies arrived on Earth, so they’ll be getting put to rest.”

“Ah hah! I had my fingers crossed this whole time. We’re saved then!”

“What are you talking about?”

“Well, you know I have the secret battle station plans, and I performed Bob and Lori’s autopsies…”

“So, what good is that? This may be the most advanced bio lab this side of Tau Ceti, but even you can’t grow a hypernode transmitter in a vat, and you can’t smuggle 100 exabytes of secret plans in a pair of corpses–”

“– I can and did.”

“What? They put those bodies through a full nanometer scan before letting them through. If there were a single molecule which didn’t belong in a human, or even the right molecules in the wrong place, that’d pick it up. And even if you get a few through, the holographic encoding of the plans means you have to smuggle all 100 exabytes or it’s useless as none of it.”

“But the scanners don’t check the DNA.”

“Sure they do. If the body’s cells don’t have the right amount of DNA in the right place, or if there’s extra DNA in the wrong place, that’ll cause a red light.”

“I meant they don’t check the DNA sequences.”

“Well, no. Everyone’s is different, and no one is going to smuggle DNA, it’s thousands of times cheaper to make it yourself, even if you have only the most rudimentary equipment.”

“The makers of the scanners weren’t thinking about smuggling information. After all, hypernode is going to be faster and cheaper than any ship. But when your enemy has control of all the hypernodes… Well, there are 3 billion base pairs in the human genome. Each cell has a copy of that genome. And there are 50 trillion cells in the body. And this equipment can replace each cell’s DNA with a unique sequence. Those plans are written into their nuclei, redundantly many many times over. And when Earth checks their DNA against the stored records for identity verification, they’ll discover sequences which aren’t human, and don’t even match any lifeform whatsoever.”

“So, we’re going to be rescued by a pair of corpses, which you turned into digital media…”

“Yes, we’re saved by the stateful dead.”

11-Sep-2012

Getting Assange out of the embassy

Filed under: humor — jlm @ 21:41

Julian Assange is holed up in Ecuador’s embassy in London, which is basically equivalent to being under house arrest, making Ecuador’s granting of asylum somewhat moot. Usually in these situations, embassy staff will hustle the asylum seeker out in a diplomatic car, but the Ecuadorian embassy doesn’t have on-grounds parking, so those few feet of British-jurisdiction sidewalk between the embassy door and the street are causing him much consternation. How might he leave the embassy grounds?

1) Stick diplomatic plates on one of these bad boys and have him step into its cab from a balcony or roof.
Hertz lifter

2) In Europe, fugitive rapists get to walk free if they’re famous filmmakers. Assange is already famous, so all he has to do is make a movie, and he can be confident the court will reverse itself on extraditing him.

3) A bunch of helium balloons will lift a lawn chair and occupant, so he can wait for a strong wind blowing to the southeast and float away to France.

I’m confident this advice will help Assange achieve his freedom!

18-Aug-2012

The thermochemistry of fracking’s natural gas boom

Filed under: science — jlm @ 20:22

If you’ve been following along, you know that over the last several years advances in hydraulic shale fracturing (“fracking”) technology have opened up large new sources of natural gas to the energy production market. The Law of Supply being what it is, this has driven down the price of natural gas, and consequently electricity generation companies have switched from preferentially burning coal to preferentially burning natural gas, as that’s now the cheaper way to get a therm. The unexpected result of this is that the United States’s CO2 emissions from electricity generation have significantly dropped.

This is surprising at first. Why does switching from coal to natural gas reduce emissions so much? After all, they’re both fossil fuels. Well, coal is polycrystalline graphite with impurities, i.e., energetically essentially all carbon. To burn graphite, you put in energy to break C-C bonds then get energy when you form C-O bonds, and your only byproduct is CO2. Natural gas is primarialy methane, with other hydrocarbons and impurities. To burn methane you break C-H bonds, which are weaker than C-C bonds, and get energy from not only C-O bonds but also the stronger O-H bonds, so methane is a more efficient fuel. On top of that, much of your byproduct is water vapor, which doesn’t contribute to global warming.

Some numbers: Burning 1 mol of either graphite or methane produces 1 mol of CO2. Graphite’s molar heat of combustion is 393.5 kJ, while methane’s is 802.3 kJ. That means you get slightly over twice as many therms from burning methane as you do graphite for a given quantity of CO2 produced. So it’s no wonder that the switchover to natural gas has reduced CO2 emission so drastically!

An unregulated market is a double edged sword for your greenhouse gas policy, however. It’s just blind luck that a lower-carbon-footprint energy source became economical. The market can just as easily make natural gas less economical, or make a higher-carbon-footprint source (e.g., tar sands) economical.

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