Blog: 2010-09

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I'm big on protocol about some things. It comes from being an engineer/scientist. Or vice versa.

A comedian friend was visiting, and it came up in conversation that refilling my Softsoap brand hand soap dispensers with store-brand bulk soap necessitates removing the labels so that they don't contain inaccurate information.

"It's just good practice," I said.

"I think it's hilarious that you remove the labels from your soap bottles for safety."

She's right that, in the case of hand soap in one apartment, misleading labeling almost certainly doesn't matter. However, I think there's an important practice here, for some fuzzy reasons: (1) it's often easier and/or more reliable to do things the rigorous way by default, than to determine whether they need to be done rigorously; (2) being in habit of doing things rigorously makes you better at it, for when it matters; (3) having most things done rigorously makes things that look non-rigorous -- such as failures or overlooked things -- stand out.

I won't get into the large-systems implications of rigor in all components, since this is just a bottle of soap we're talking about.

PSA for New Students in Boston

Students new to the Boston area and acquiring bikes, check out the video by Katie Koch and Nicole Ciorogan at Boston University.

Also, I don't know about Boston proper, but in Cambridge, be especially aware of dooring. What happens is that you're in the bike lane, and some parked vehicle opens their door into your lane right in front of you. Crashing into the door is not the greatest of your worries -- you can also be thrown into the auto traffic a couple feet away. When in a bike lane along parked cars, always watch for opening doors and have a reaction in mind.

Fabulous Flats

I've been trying Fabulous Flats bread lately, and like it for making sandwiches.

It's about the same calories as a hamburger bun, but more structural when made to fit in one's mouth, and tastes better.

It's hidden on the bottom shelf at my nearest Whole Foods.

Massachusetts Bans Texting While Driving

The new law, signed by Governor Deval Patrick in July, bars drivers under age 18 from using any mobile electronic device while driving, bars drivers 18 and older from reading or writing text messages or e-mails or searching the Internet at the wheel [...]

—Eric Moskowitz, "As ban nears, state spreads word against driver texting," Boston Globe, 2010-09-21

I'd like to think that this sort of law would not be necessary, but then I looked anecdotally at the practice of driving in the Boston metro area. If you were brought up to be responsible in your conduct, or you are from somewhere that drivers are not known throughout the region as "Massholes," I bet that you would be shocked at the prevailing practices.

Just the other day, in a dense, walking- and biking-heavy part of Cambridge, while waiting to cross the street at a 4-way intersection of 2 major streets in heavy traffic... I saw a driver plow through with his attention focused on what appeared to be a cellphone in his hand. I then watched the chain of vehicles following him, and here's what the drivers of the next 4 vehicles appeared to be doing: 1 texting/viewing cellphone, 1 talking with cellphone held to head with hand, 1 eating half a citrus fruit, and only 1 with attention presumably on the road and both hands available to operate the vehicle.

Cell phone use is far from the only inadvisable driving practice in the Boston area. Three cars blowing through each red light is the norm in some especially dense parts of town around universities, for example. The outlier behavior is even worse.

At least one of the universities stations police cruisers at some of the crossings sometimes, just for traffic-calming effect. If they did not do this, I believe that each September we would see a coupld new undergrads and grad students from more civilized areas struck by cars before word got around.

It's not only irresponsible jerks who exhibit some of the driving practices of Massholes: it's become the social norm. On a few occasions when someone has called me, the conversation has gone like this:

A: Wait, are you driving right now?
B: Um, yes. [Or a very cute guilty toddler act]
A: I'm hanging up on you now.

(Note: This hard-liner stance is not conducive to retaining girlfriends.)

Now that there will be a ban on texting, if only we can get people to curtail talking on a cellphone while driving, which can be a deadly cognitive distraction. Otherwise, I could see that eventually being banned too, or, worse, some ill-advised technological measures being deployed.

When Not to Talk Like a Pirate

When debugging some SSL stuff at 3am Sunday morning, and Googling about SSL renegotiation in OpenSSL, I landed upon 9-year-old article that I thought just might have a gem of a sentence buried in it that answered my question. Unfortunately, some "journal" site with pretensions of reputability has seen fit to feed their technical articles through a pirate-speak filter.

If you already thought that SSL and OpenSSL were overly messy, just wait til even the simplest sentence of documentation is obfuscated like:

SSL makes a distinction betwixt a connection an' a session. The sharks will eat well tonight, Ya horn swogglin' scurvy cur!

Here's what would be a straightforward paragraph that one normally might want to read closely:

The first time a client an' server interact, they create both a new connection an' a new session, pass the grog! If th' server is prepared t' resume th' session, it assigns th' session a session_id an' transmits th' session_id t' th' client durin' th' handshake, Ya lily livered swabbie! Aarrr! The server caches th' master_secret fer later reference. When th' client initiates a new connection with th' server, it provides th' session_id t' th' server. The server can choose t' either resume th' session or force a full handshake, I'll warrant ye. If th' server chooses t' resume th' session, th' rest o' th' handshake is skipped, an' th' stored master_secret is used t' generate all th' cryptographic keys.

Forget about skimming headings quickly:

Listin' 2, Avast me hearties! Aarrr! Activatin' th' Server Session Cache

And "lubber" pages?

This allows fine control o'er th' verification process but is too complicated t' discuss here. Check th' OpenSSL lubber pages fer more detail.

Perhaps the discussion would be uncomplicated enough for inclusion, were the instructor not hobbled by self-inflicted language impairment.

Keep this pirate-talking crap away from useful text, and save it for worthless text like blogs.

Decrypting HTTPS in Wireshark

If you're trying to debug HTTPS (SSL/TLS) traffic in Wireshark, first you need a Wireshark that's built with that support, and to have the server private key and such. Less commonly known, you need to disable problematic crypto like DH key exchange.

The quick way to dumb down your crypto in Apache sufficiently is with the config file option:

SSLCipherSuite RSA

Decrypting sniffed SSL should not normally be necessary. Usually SSL should just work, and you can get the plaintext from server or the client side. In this case, however, some SSL library wasn't sending the expected protocol.

Old Strobes

Don't throw out that old, seemingly dead camera flash.

At lunchtime today, I picked up an old, used Nikon SB-24 strobe to send to my padawan overseas. I went with the SB-24 because it's a high-quality strobe with manual controls, even though I could've gotten a more impressive-looking new cheapo one that does fully automatic i-TTL for around the same money. And I am too much of a cheap bastard to pay 5-10 times as much for an SB-900 with manual controls.

This SB-24 was previously owned by a major California newspaper, and initially seemed DOA. Eventually I tried cleaning the battery terminals, and that did the trick. It also seemed to need to unstick its zoom motor and perhaps warm up the capacitor for the first time in a long time. In all testing since then, it's worked perfectly, with excellent refresh and everything.

Related blog entries on old Nikon strobes: SB-28 foot replacement, mounting crappy wireless trigger on old strobes, cheap flash grids, cheap old flash meter for cheap old strobes, and more comments on old strobes.

There are also blog entries on high-power studio strobes and on Canon E-TTL II strobes. The quick brain dump is that, were I doing fashion photography, I'd go back to high-power strobes for the refresh speed, and that the Canon strobes are great for on-camera photojournalism use, and for the 1/500 sync with ST-E2 for dance photography. For portraiture and fine art, a more sensible setup is a few old Nikon SB units (or AlienBees) and optical slave triggers (or maybe Radiopopper Jr.).

I'll add that, despite what Canon EOS evangelists have claimed, I found getting artsy lighting ratios right with multiple 580EX units to be nigh impossible in some cases that would've been trivial with my old manual SB-28 setup. Nikon is better than Canon about putting manual controls and sync terminals into its otherwise comparable strobes. Even though I don't do photography anymore, I wish I'd kept at least a couple of my old SB-28 units, just for the occasional headshot for a friend.

Earlier to... 2010-08

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