$title is something that has always confused me.

But I learned the correct answer today: it is neither.

The precise instant that is “noon” is the “M” in AM and PM (ante- and post-meridiem). So noon is properly “12M,” though the spoilsports at Wikipedia term this usage “antiquated.” (They do go on to call the modern US GPO style manual incorrect, though.) More modern usage appears to be to just say “12 noon.” But if you’re referring specifically to noon, “12am” or “12pm” are both incorrect. (In the same way that the year 2000 was neither pre-2000 nor post-2000.)

This does clear something up for me, though! My confusion has typically been about the whole hour of 12:xx. Is 12:30 (30 minutes past noon) a.m. or p.m.?

It turns out that I have been wrong. I assumed it was a.m., and that the switch happened when the 12 rolled over to 1. But the pedantic clarification of what a.m. and p.m. means makes this suddenly intuitive:

11:59:59 a.m.
12:00:00 M
12:00:01 p.m.

The equivalent for midnight is less clear, but it seems as though “12 p.m.” is generally accepted, with 12:00:01 being a.m.

Now you know.

A while back, I somehow became interested in gold. I’d seen a few references to people investing in gold—physically buying gold coins. The idea is that gold holds its value well, and has been used as currency for millennia. So it sees use as a hedge against the dollar—when people worry about the dollar losing value, they buy gold. Seems pretty reasonable!

But as I started to look into it, my doubts grew. I’m now of the opinion that gold is a terrible investment, especially for the claimed purposes. Here’s why.

First, I’ve seen it said that gold holds its value very well, and is very stable. Here is a graph, from Kitco.com, showing the price of gold from 1995 to today:

If you’d have invested around the turn of the century (I love that “turn of the century” now means 1999-2000), you’d have done very well for yourself. But would you want to invest now? It’s true that past performance doesn’t indicate future performance, but this isn’t exactly the type of graph that makes me see a huge opportunity. But my point isn’t to argue that gold has “peaked,” or anything of the sort. My point is just that if someone tells you that gold is a very stable investment, they are lying through their teeth. In a 10-year period, gold went from below $400/ounce to over $1800/ounce. And since 2011, it’s lost about $500/ounce in value.

Gold also seems to attract some nutty conspiracy theories and strange beliefs. A lot of place sell pre-1933 gold. I spent a while trying to figure out why. And, well, here’s why: back in 1933, the government started seizing gold coins for a brief period of history. Some worry that the government will do this again, but believe that gold coins from before 1933 are exempt. This belief is, of course, wildly inaccurate. The linked article does a good job factually debunking it. (For those less inclined to care about facts, but fond of conspiracy theories, I might argue this—if the government were to overstep its authority and confiscate privately-owned gold in the modern era, what makes you think that they would honor a misinterpreted rule from the 60s and leave your pre-1933 gold untouched?)

I should disclaim that I’m not an investment expert, and that I’m not really trying to argue that savvy investors could never see gold as a good investment. If you’re a financial wizard and want to put some money in gold, by all means give it a try. What I am saying is that, if you’re a senior citizen who saw the commercial I saw on TV about how the dollar is going to lose its value and your safest bet is to buy gold, you are being had.

But when you see ads on TV trying to sell you gold, you might consider their motives. If I believed gold was going to keep climbing in value, I’d be buying up all the gold I could get. But suppose you were sitting on a lot of gold and saw the graph I linked to above. Wouldn’t it seem really tempting to try to convince people that the dollar was going to fall and that they’d better buy all the gold you were selling right away? You’d be rid of your rapidly-depreciating gold, and left with plenty of cash in a time when the stock market is hitting record highs.

In conclusion, please do not buy gold without doing a lot of due diligence. Maybe gold is a good investment in certain situations, and maybe gold was a good investment a decade ago. But that doesn’t mean that gold is a good investment for you, today.

…and other information about airplane engine failures.

I’ve sometimes wondered why airplanes don’t seem to fly in straight lines. I once saw someone give a seemingly-simple explanation: the Earth is round. While that fact is true, it doesn’t really explain it. When I flew from New York to Hong Kong, “curvature of the Earth” doesn’t explain why we practically flew through the arctic circle. It was certainly not the most efficient path.

I suspect there are many components to the answer, and perhaps the earth’s curvature factors in a bit. I also suspect that weather and wind factor in. But there’s one big, glaring reason that I’ve found: a twin-engine airplane must, at all times, be able to reach an airport on a single engine within a certain period of time. Early on, the limit was 60 minutes, though that figure has gone up over time.

The idea was simple—with only two engines, if one fails, you want to be able to land pretty quickly. So the FAA set a limit of 60 minutes. This surely had all sorts of positive safety implications, but it was also inconvenient, and led to some circuitous routes, plus some areas just not being possible to reach in a twin-engine plane. Over time, apparently, evidence allowed these rules to be relaxed. For one, it turns out that a plane is capable of flying just fine on a single engine.

For example, here is a rather chilling video of an airplane (a Boeing 757) ingesting a bird into one of its engines during takeoff, causing the engine to spew flames until it is shut down:

It continues its takeoff normally, declares an emergency, and lands normally a few minutes later. If you ignore the flames during takeoff and the inspection by the fire department upon landing, it looks entirely normal. Also fascinating to me is how the pilot seems entirely calm during the whole situation, and how half of the radio traffic is just about how they’ll be able to exit the runway normally so other flights shouldn’t need to divert, and how they plan to taxi back.

While a video of an airplane engine spewing fire might not inspire a lot of confidence, what’s intriguing to me is that the plane flew just fine with only one engine operating. It didn’t begin flying sideways or have difficulty landing as I might have naively expected. Hence the initial justification of the 60-minute rule—if an engine failed mid-flight, pilots would be able to safely fly to the nearest airport with only one engine.

Over time, apparently, evidence showed that spontaneous failure of an engine mid-flight was extremely uncommon, and that the 60-minute limit was excessively conservative and made many flights impractical. Over time, allowances of up to four hours have been granted, and newer planes are being certified for times in excess of five hours. But many older planes are still limited by shorter times, hence the seemingly-odd routes they take—they need to stay within range of airports.

FUD and Proxies

In: Uncategorized

15 Feb 2014

I sometimes wonder how many people who use proxies / VPN service / Tor actually understand how the Internet works.

To be sure, there are lots of reasons to use them. Want to access geo-restricted content? Tunnel your traffic through a proxy in a region that works. Want to hide your identity? A proxy / Tor can help.

Want to remain secure online? A proxy / VPN / Tor is a horrible idea!

Take, for instance, the description of this product, which appears to be a Tor ‘router’ in hardware. (There is, of course, absolutely no reason you need a hardware device. You could just, you know, install Tor on your computer for free.) It says, in part: “Each time you venture out onto the web, you’re vulnerable, because each site can access your IP address, giving them the ability to find your physical location. With Safeplug, you can feel safe on the internet again, browsing anonymously and securely.”

They can “access your IP address”? That’s how the Internet works! It would be like denouncing telephones as unsafe because, when you call someone, they can see your phone number and, from your area code, deduce your location. (Although the Caller ID argument is fallacious. You can block Caller ID, but you can’t block an IP–you can only route your traffic through someone else’s computer, so that sites see that IP.)

It’s right about browsing anonymously. It’s good for that. But securely? It couldn’t be more incorrect! You’re routing your traffic through an unknown stranger’s computer to stay anonymous. That person can see everything you do. It’s not just paranoid and not-tech-savvy people that fall for this–it’s how numerous embassies had their passwords exposed and web traffic seen, by forgetting how the service works.

In defense of Uncrate, they do explain how it works, by saying that it “routes your internet traffic through a series of random locations, making it impossible to determine where you are.” If your goal is anonymity, Tor might work. (If you’re careful.) If your goal is security, though, perhaps consider that “rout[ing] your internet traffic through a series of random locations” is about the most unsafe thing you could do.

I’m not arguing that one should never use Tor or an anonymous proxy. I’m just arguing that using them for, say, online banking, or confidential communication, is quite ignorant. (Unless you’re excellent at using encryption.)

(No, no, I’m not actually selling anything, and this isn’t spam. But some of us have been parodying the weird “One weird trick” ads that no one understands. I did it in my post about getting NFS working, and my friend and colleague Tomas introduced his Gerrit expand comments bookmarklet as “one weird trick” to make it more usable. This one is about batteries.)

For years, I’ve been plagued by what to do about the things I own that use AA/AAA batteries. On one hand, disposable batteries are really convenient, because they last years in storage, and are always ready. But the idea of throwing away batteries weekly becomes morally objectionable the more you think about it. On the other hand, you have rechargeable batteries. They can be used hundreds of times, solving (or at least exponentially reducing) the disposal issue I have. But I’ll often endure a wait of a few hours when the batteries in something die and I have to go hastily recharge them. So often I’ll charge things when the batteries aren’t really all that low, so that they won’t run out at an inconvenient time, and that’s just a hassle.

So the “one weird trick” is simple: buy a ton of Eneloop batteries, more than you need, and use them first-in, first-out. Throw depleted batteries on the charger as you grab the new ones to ensure you never run out. It’s the best of both worlds. You always have fully-charged batteries on hand, but instead of throwing the depleted ones in the trash, you put them in the charger. Here it is in a diagram:

Sequence diagram

I really can’t begin to describe how incredible this is. It’s like this amazing luxury I have. But there are some things I figured out along the away:

  • You need to get something that’s got a very low self-discharge rate. This is the selling point of the Eneloops. You can charge them and they’ll still be good a year down the road. (They’re not immune to self-discharge, but it’s greatly reduced.) This system just will not work at all with regular batteries. Otherwise when you charge a battery and return it to storage, it will be drained by the time you use it. Seriously, this bullet point is absolutely critical.
  • Get all the same type of battery. Different brands, or maybe even different models of the same brand, discharge at different rates. It becomes a lowest common denominator situation if you mix them. If you must use different brands/models, don’t mix them in the same device.
  • Buy a ton of batteries. I figured I’d need maybe ten AA batteries. I actually have about 25-30 in circulation, four in reserve (charged and ready to go), and four that I just replaced. You think you got everything, and then the batteries in something else die and you realize you need more. Because they last a long time between charges, having a dozen extra batteries is not a problem. Having too few batteries is.
  • You must force yourself to always put the dead batteries on the charger as you grab new ones. Keep the reserve (charged batteries) and the charger next to each other. This is absolutely essential. You will just have a pile of dead batteries otherwise.
  • Go strictly first-in, first-out on batteries. Work left-to-right, front-to-back, or whatever. I’ve often been tempted to take the batteries off the charger and use them, since they’re “fresher” than the ones waiting in reserve. But the whole point of this system is that the ones in reserve are perfectly good. Once you start skipping over batteries, that guarantee starts to break down.
  • If you have new disposable batteries in reserve, use them first. It pains me to use them and then throw them away when I have perfectly-good rechargeable batteries, but the alternative is to not use them and throw them away. Use them while they’re good, knowing that you will never purchase a disposable battery again.

Eneloop batteries are really expensive. $2-3 per battery. But this is absolutely a case of paying for quality. It’s also a wise investment—you’re going to use these hundreds of times, such that the per-use cost of each battery is probably under a cent. I highly, highly recommend the Eneloop brand. There may now be other low-self-discharge batteries, but I haven’t tried them. Whatever you do, be absolutely certain that batteries can last a month or two without losing much of their charge before you buy them. It is a complete waste of your money otherwise.

I highly recommend some specifics, too:
* A good charger. I have, and would recommend, the LaCrosse BC-700. It is not particularly intuitive to use, but it’s not too tough to master. It allows you to discharge and then recharge batteries, which can help extend capacity early on. ([citation needed] on that, but I’ve read it multiple places.) However, this is just the model I bought and that I like; any quality charger should work fine.
* A container for the batteries. I don’t have a specific product recommendation here, though the linked set is good. (Note that some retail-packaged Eneloop batteries come with these, so you might not need to purchase them separately.) I have a container that holds 8 that I use for my main reserve set, spilling over into 4-packs when it fills. I do recommend that you get one that only holds one layer of batteries, to make the first-in, first-out system easy and intuitive. Take batteries from the right, and insert from the left. No worrying about top and bottom rows or anything. Really any container will do, but don’t just leave them lying around or it will just become a mess and you won’t know what’s what.

This all sounds so silly, but it’s incredibly useful. I would never go back to any other system.

CNN Money just named Westford, MA as the #11 small town in America, including a mention of my employer’s big presence there.

I was really pretty worried when I saw people quoting what they referred to as a comedian on the subject of the attacks in Boston. I wasn’t ready for someone to joke about it. But I took a look anyway, and I realized — comedians don’t just tell jokes. Sometimes they are absolutely fucking brilliant.

If you haven’t already read it, you really owe it to yourself to read Patton Oswalt’s Facebook post. Seriously. Read it. Now.

As a commentary on the bombings of the Boston Marathon, it’s absolutely brilliant. And that’s why it was written. But it’s not just about that. It’s about life, and the world we inhabit. It’s a credo for life:

But the vast majority stands against that darkness and, like white blood cells attacking a virus, they dilute and weaken and eventually wash away the evil doers and, more importantly, the damage they wreak. This is beyond religion or creed or nation. We would not be here if humanity were inherently evil. We’d have eaten ourselves alive long ago.

So when you spot violence, or bigotry, or intolerance or fear or just garden-variety misogyny, hatred or ignorance, just look it in the eye and think, “The good outnumber you, and we always will.”

It’s a thousand times more eloquent than I could have put it, and it’s such a great message to keep in mind in a world where sometimes horrible things happen.

When I traveled to London last year, I stayed in the Premier Inn at London County Hall. It was a great hotel in a great location.

But I just got this email from them:


I don’t think they understand how email works. Giving me advance notice to opt out of spam I didn’t ask for doesn’t make it okay. Consider the following:

Dear Premier Inn,

If I don’t hear from you by 17th March, I’ll assume you’re happy for me to regularly mail you expired food from my refrigerator regularly — and to kick things off, I’ll send you some expired fish very soon.

Best wishes,

Disgrunted customer

See? That’d be patently unreasonable. (But immensely satisfying.) Why is theirs any different? If I actually wanted their “special offers,” how about letting me ask for them, versus informing me that they’re going to start sending them to me until I demand they stop?

When in London, stay somewhere else!

I’ve used Gmail for ages, but have historically been less than impressed with its appearance. I’m all for a simple interface, but simple and ugly don’t have to go together.

I’ve changed through their themes over time, never quite happy with the options. But more recently, I discovered that they allow “custom” themes. (Quotes around “custom” since your choices are just “Light” and “Dark” with a configurable background.)

But that turns out to work pretty well:

(I’ve heavily redacted the contents of my Inbox, just since I’d be pretty irritated if a friend of mine went blogging photos of my emails to them.)

There’s a great selection of really nice backgrounds to choose from, including the ability to use your own photos. But thus far I’ve been so happy with the options that I haven’t tried to use my own photos. You really owe it to yourself to try out.

(No word yet on whether the monkey in my background is Darwin or not.)

When I traveled to Europe and back, I switched through timezones a lot. I went from Boston to London. When in London, Boston switched off of DST. Then I moved from London to Brno, forward another hour. Then back to London, then back to Boston.

Not wanting to lug my heavy Thinkpad around, I brought my MacBook Air on the trip. (And was appropriately ostracized by coworkers for bringing a Mac to a meeting at a company best known for its Linux distribution.) And it did something that kind of intrigued me — it automatically adjusted to the local timezone.

Now, this shouldn’t be possible. My clock is synchronized using NTP, which exchanges UTC time, deliberately ignorant of timezones or DST. And even if NTP did use local timezones (which would be a huge disaster), it still wouldn’t have worked, because I had hardcoded some local clocks.

Investigating a bit, I found this. This is seemingly a new feature, and it uses the operating system’s location service to find your timezone. My computer doesn’t have an onboard GPS, of course, so it’s doing one of two things — GeoIP, and/or looking up the access points I can see against a database.

This is really neat, but it’s also pretty damned creepy. Here is what I see when I visit that setting:

It knows exactly where I am.

I’m willing to bet it knows exactly where the closest tinfoil hat shop is, too.

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