What I Learned Today

Every since I discovered The Teaching Company’s excellent lecture courses, I’ve been a fan. Apparently, Orson Scott Card is too. He wrote an article about how great the Great Courses are (scroll down about 3/4 of the way). I know just what he means when he writes:

“Why am I going on about these courses? Because I believe education should never end. I don’t think education is something you “get,” and degrees don’t impress me. […] the truth is I read constantly, and take these course[s], for love. It bothers me when there are things I don’t know or don’t quite understand. I hate it that I only speak a couple of languages. There just hasn’t been time to learn all that I’ve wanted to in my life.”

He recommends the following Great Courses professors:

• Brian Fagan: human prehistory
• Elizabeth Vandiver: Herodotus’ history
• Jennifer Paxton: medieval English history
• Kenneth R. Bartlett: history of Renaissance Italy
• Louis Markos: writings of C.S. Lewis
• Marshall C. Eakin; discovery and conquest of the Americas
• Peter Rodriguez: economics
• Philip Daileader’s three courses on early, “high” and late Medieval Europe
• Robert L. Dise Jr.: ancient empires before Alexander the Great
• Scott McEachern: origin of civilization: “begins badly – start with lecture 3”
• John McWhorter: intro to linguistics: “best teacher I’ve encountered in the Great Courses so far”

… none of whom I’ve yet sampled. My own current favorite is Prof. Rufus Fears, who created the excellent “Books That Have Made History: Books That Can Change your Life” course (currently discounted). I’m not sure I always agree with his conclusions, but the aim of a great course should be to inspire you to think on your own, not just adopt every opinion and interpretation professed by the instructor. Dr. Fears is always entertaining — sometimes a bit excessively so, as when his lectures become more of a dramatic reading or interpretation of the book under study than an analysis of the great ideas and themes it contains. I am eagerly working my way through this course and hope to learn more from him in the future.

Given Card’s recommendation, I may also be trying Prof. McWhorter as well! I’ve always been interested in linguistics, but have never taken an official course on the subject. A “Teach Yourself Linguistics” book is on my to-read list. Maybe McWhorter’s course will be the impetus for finally making that happen. As Card notes, the best strategy is to wait until the course you’re interested in goes on sale — their sales are phenomenal. Meanwhile, I also have “Building Great Sentences: Exploring the Writer’s Craft”, “The English Novel”, and “Stress and Your Body” to enjoy and learn from. Here’s to an educational sabbatical!

There are all sorts of ways to look up a book in the library: by author, by title, by subject, by call number… But today, a patron approached me with only the book’s ISBN and asked me to locate it for her. Fortunately, the catalog system does permit searches on ISBNs (and even better, the computer had a numeric keypad to make entering it easy), and I quickly found the book, got the call number, walked the patron through the shelves, and whipped out the book, as if by magic. :) As I was leaving, she asked, “What is this thing, this ISBN?” and I realized that I didn’t actually know anything about ISBNs as a concept, not even what the acronym stood for.

An ISBN is an International Standard Book Number. The original (non-international) Standard Book Numbers, created in 1966 for booksellers, used 9 digits. Its derivative, the ISBN, has grown from 10 to 13 digits, as ISO, the international body that governs such things, noticed that more and more books were being created.

Even more interesting, the 13-digit ISBN has structure. It consists of:

1. a GS1 prefix (978 means book publishing)
2. a group identifier, which seems to indicate its country of origin
3. a publisher code (one of 628,000)
4. an item number
5. a checksum or check digit

Take for example the mouth-watering book Geographies of Mars. The ISBN found on its back cover is 978-0-226-47078-8. We know therefore that this is a book (978), from an English-speaking country (0), by publisher 226 (University of Chicago Press), and it is item 47078. Because the publisher code takes 3 digits, by convention the item gets 5 digits.

The checksum, ah, now that’s fun. Checksums are commonly used to detect whether or not something was lost in transmission. A checksum value is computed over a block of data before it is sent, and then the receiver can compute the same value on what was actually received and see if it matches. If not, it requests that the data be re-sent. (Note that the error could have occurred in the data or in the checksum itself, which is also transmitted; either way, it’s safest to retransmit the data.)

Here, the checksum (digit) is computed over the first 12 digits in the number. This allows bar code scanners to confirm that they’ve correctly scanned the number, or to rescan it if not. (Or a manual entry system to alert the user if they type in an invalid ISBN.) The algorithm for the ISBN checksum reads like an exercise for an introductory CS course (oh wait, someone already thought of that, and someone else, and someone else…):

Each digit, from left to right, is alternately multiplied by 1 or 3, then those products are summed modulo 10 to give a value ranging from 0 to 9. Subtracted from 10, that leaves a result from 1 to 10. A zero (0) replaces a ten (10), so, in all cases, a single check digit results. [from wikipedia]

So for my example book, we have 9+7*3+8+0*3+2+2*3+6+4*3+7+0*3+7+8*3 = 102. Then 102 mod 10 is 2, which we subtract from 10 to get 8. And sure enough, the final digit in the ISBN is… 8! Checksum complete!

And now I’ll be able to answer that question about ISBNs promptly, should it ever come up again. Next up: memorizing the Dewey Decimal System.

I recently finished the delightful “Making Tracks: An American Rail Odyssey,” which is one man’s tale of his trek via Amtrak across the U.S. in the mid-80’s — a travelogue interspersed with absolutely fascinating railroad history. Here are a few of the bits that stuck with me:

• The first transcontinental line was laid across the Rockies, not because it was the best or cheapest or easiest route, but because of (get this) the Civil War. An easier southern route through New Mexico and Arizona was the most likely choice, but then war broke out and all of the South became distrusted. And yet the transcontinental railroad was seen as a unifying goal, critical to holding us together as one nation. And so the Union Pacific line through Denver, Cheyenne, and Salt Lake City was born. Politics can bend even iron, it seems! Trains were also used extensively to transport troops during the war, and track sabotage (and repair) was rampant.
• Apparently there was actually a plan to put ICBMs on trains, as a way to make them mobile and therefore harder to take out preemptively. Wow.
  

  “As of this writing, the final decision to place intercontinental ballistic missiles on railcars has not yet been made, but the plan is far enough along that the military already has designed a ‘Rail Garrison’ logo featuring a train superimposed on a missile, with an American flag, and two strands of Nebraska wheat with the inscription ‘Peacekeeper.’ The impetus for the plan is the fear of a possible enemy first strike that might disable the 1,054 missiles located in fixed concrete silos. […] When a launch order is received from the President, the train can stop in three minutes. It takes an additional five minutes to reorient the missile’s guidance system. During this time the car’s roof doors open and the missile is raised into firing position. With a blast of steam, the missile is ejected from its canister and then fires its engines above the train and begins its flight.”

• As late as the late 80’s (when the book was written), manual labor is/was used to adjust and repair track! A team can replace a tie in 7 minutes, which works out to 100 feet of track per day. A far cry from the 10 miles of track that Charles Crocker’s Chinese workers laid in 1869, but then that’s a record that’s never been surpassed.

And there’s so, so much more to read and enjoy in this book. Highly recommended!

Here is a great critical summary of the book, and my own review as well.

Many have heard of the Mohs scale of mineral hardness. But did you know that there’s a similar scale for how “hard” a given piece of science fiction is?

Friedrich Mohs anchored his scale with talc (softest, 1) and diamond (hardest, 10). Students of Mineralogy are usually taught to assign hardness based on which of the standard 10 minerals mark the new one, and which don’t. There is also a device called a sclerometer (I’ve never seen one) which employs a diamond head and determines how much pressure is needed to create a visible scratch, or alternatively uses a fixed amount of pressure and measures the width of the resulting scratch.

But now, there is also a scale of science fiction hardness! This page also includes examples of movies that fit at every level of the scale, which ranges from 0 (Barbarella, MST3K, Hitchhiker’s Guide to the Galaxy) to 8 (Real Life). If I were to rate the last few books we read in my sci-fi book club, I’d choose (note the caveat that harder doesn’t equal better!):

• The Handmaid’s Tale: about 7.5, but is this really sci-fi? Technology isn’t really a player, except as an evil shadow lurking in the past.
• The Shockwave Rider: a 7; no FTL or broken laws of physics, and eerily prescient about today’s (and tomorrow’s) computer networks.
• The Atrocity Archives: about 2. There’s no actual space flight, but there are demon-spawned gates to permit travel to other planets (and universes?), with some handwavy handling of pressure differentials and energy conservation. Physics is pretty much entirely broken by the integration with pentagrams and the occult. But hey, it’s fun!
• Bones of the Earth: right about a 1. Not only does time travel exist, but there’s also a “paradox detector” (never explained).
• Metatropolis: varied, but about a 7 once you take today and add in various bits of technology and virtual reality overlays. All reasonable extrapolations, without any laws of physics being broken.
• The Demolished Man: about a 4, if you consider telepathy to be breaking a law of physics. Tenser, said the tensor!

The sci-fi hardness scale page also puts Contact, Avatar, and Ender’s Game at a 3, and Rainbows End and Cryptonomicon at a 5. I’d put Anathem at a 5, too.

How hard is your sci-fi?

Henry David Thoreau keeps a fun and thought-provoking blog, based on his diaries. A recent entry caught my eye with its use of a word that was new to me: hypaethral. This adjective describes something that is open to the air, as a building lacking a roof. Thoreau’s use of it here is amusingly metaphorical:

“I thought that one peculiarity of my ‘Week’ was its hypaethral character, to use an epithet applied to those Egyptian temples which are open to the heavens above, under the ether. I thought that it had little of the atmosphere of the house about it, but might wholly have been written, as in fact it was to a considerable extent, out-of-doors. It was only in a late period in writing it, as it happened, that I used any phrases implying that I lived in a house or lived a domestic life. I trust it does not smell [so much] of the study and library, even of the poet’s attic, as of the fields and woods; that it is a hypaethral or unroofed book, lying open under the ether and permeated by it, open to all weathers, not easy to be kept on a shelf.” — Henry David Thoreau, June 29, 1851

I like the idea of a book without a roof, one that would be hard to keep on a shelf, and one that would bring a taste of all the outdoors to any who passed near it. And many’s the day I’ve wished (though lacking the word) that my own life were more hypaethral — that I might look up from my computer and see the sky arching in dazzling blue above, or, later, feel the flickering chatter of stars rain down on me from the dusky twilight. The reminder to look up, to elevate our attention, to imagine the vastness of what lies outside our 12-foot ceilings and plaster and paint, is always a welcome one. Thank you, Thoreau!