Ends in X

Yesterday “Raised by Penguins” got its ISBN, and I was surprised to see that it ends with an X. That’s right, nine digits, followed by the letter X.

Confused and bewildered, I Googled for some kind of explanation for this aberrant character. I found it here: Mathematics and Writing in Action: The International Standard Book Number Check Digit Scheme.

The ISBN Check Digit Scheme

For a1a2a3a4a5a6a7a8a9a10, the ten digit ISBN, the check digit a10 is appended to the nine digit identification number a1a2a3a4a5a6a7a8a9 such that a10 satisfies the equation

10a1 + 9a2 + 8a3 + 7a4 + 6a5 + 5a6 + 4a7 + 3a8 + 29 + a10 = 0 (mod 11)

If the check digit a10 is 10, the letter X is used instead.

The remainder when a number is divided by 11 could be any digit from 0 to 9 or the number 10. Since the ISBN scheme uses modulo 11 arithmetic and wants the check digit a10 to be a single character, it assigns a10 the value of X when 10 is to the check digit. The ISBN for the book Linear Algebra and its Applications, by David Lay, is 0-201-52032-X. The X indicates that the check digit is the number 10.

So X, as it turns out, is a legitimate character for an ISBN, and my book has one. Great, except that the catalog form at Cafe Press rejects any letters in the ISBN.

Furtive conversations

A rumour was spreading. Words were exchanged in hushed tones by the photocopier. In furtive conversations in darkened corners, news of its arrival passed among the cubicle dwellers of the sixth floor.

I was cleaning my coffee mug when I heard. I won’t reveal names, so let’s call her “X”. Her name doesn’t really start with an X, so don’t look for her in the company phone list.

“Do you, uh… hold on.” she began, and checked the door to see if it was clear. She leaned towards me confidentially and indicated my coffee mug. “Do you drink coffee?”

As I dried my mug, I confirmed that, yes, I drank coffee. I turned and shuffled towards the vending machine, wondering where exactly X was going with this.

“You know about… upstairs, right?” she asked. No, I hadn’t, I said, and just as I reached to select a cup of “Hawaiian” blend from the vending machine, she grabbed my wrist and said, “It’s true. It’s TRUE. They have real coffee. I’ve seen it.”

“What?” I recoiled involuntarily.

X pressed on, “The others think I’m mad, but I found it! The fabled COFFEE MAKER OF THE SEVENTH FLOOR!!!” Her shouts prompted a nearby cubicle dweller to shush her. She pulled me physically away from the vending machine behind the water cooler. “You don’t need to drink this… this… filth,” she spat. I wiped my face with my sleeve.

“Thank you,” I said, “for the tip. I just wanted a cup of coffee really.”

“No!” she hissed. “You must find it. You must seek the Coffee Maker of the Seventh Floor and drink of its…er…”

“–of its coffee?” I suggested.

“It is not merely coffee,” X sneered. “It is the purest of sources. It is the black nectar of the gods.”

“That sounds…uh…nice,” I agreed, glancing at my watch.

“Yes,” she nodded. “It is… nice.” At that, X slipped a scrap of paper into my hand and slipped out of the kitchen, pausing only to say, “It is up to you. Find the source and bring back a thermos. A thermos filled with the nectar of the gods!”

“Ssshhh!” said the cubicle dweller.

Back at my desk, I examined the scrap. It was a CD liner from the MSDN CD library. On it, in red ink, was a hand-drawn map that led to an “X”, beside which it said “coffee maker”.

So it began: my quest for the the fabled Coffee Maker of the Seventh Floor. I would not rest until I found it, if only because I was afraid of being cornered by X by the coffee vending machine again.

New perspective on an old patty

In the past few months, I’ve been very good about lunch. Oh, I still eat awful things, like big stacks of deep fried things with noodles, and choke down foot-long cheese-steak subs, but for the most part I’ve entirely eschewed the Scottish restuarant.

Until today. Today I had a bit of a lapse. As I walked past McD’s, stomach grumbling, I found myself walking in the door, against all better judgement. And as I chewed the first bites of a “Big eXtra” burger with “cheese” (that one definitely has to go in quotation marks), it struck me as never before that McD’s “beef” (also should be in quotes) tastes remarkably like oily foam rubber.

No, there was nothing wrong or different about this particular McD’s burger — I suspect that they’ve always tasted like that. I just hadn’t previously been away from them long enough to truly appreciate how awful they are.

The fries, on the other hand, are full of lovely tallow-ish flavour, and give you a full week’s worth of salt in only one serving. Hold on a sec–

*cough* *cough*

Come on heart–

*cough* *cough*

Ah. There it goes. I’m ok now. Yes, I can’t get enough of those fries.

Tech writer humour

RoboHelp is probably the most popular tool that technical writers use to create help and on-screen user guides for Windows applications. Ironically, when you select Help > Contents in RoboHelp, their own help system fails to open.

Inconvenience store

I think the “7-Eleven” name on the corner store actually means there’s between 7 and 11 customers waiting for the slow cashier. Or maybe it’s an estimate of the time you’ll spend in line.