SVN Branch Management Link-a-rama

Posted on November 14, 2009 by Karl

Submerged: CollabNet’s Subversion Blog: Branching Strategy Questioned

CMCrossroads: Robert Cowham: Branching and Merging – An Agile Perspective

CMCrossroads: Steve Berczuk. Robert Cowham, Brad Appleton: An Agile Approach to Release Management

Worth Repeating: Rob Pike “Data dominates.” and Frederick Brooks “Representation is the Essence of Programming”

Posted on November 14, 2009 by Karl

Rob Pike is a famous name in programming with a history going back to Bell Labs, co-author of two often quoted books, and today works at Google.

Back in February 1989 he wrote an essay, “Notes on Programming in C” which many consider contains insight to the “Unix Philosophy”.

One of the sections of the essay people focus on were six rules he listed on complexity. Rule number 5 is:

“Data dominates. If you’ve chosen the right data structures and organized things well, the algorithms will almost always be self evident. Data structures, not algorithms, are central to programming.”

I’ve seen people summarize that rule (why summarize three sentences?!) into “write stupid code that uses smart objects”, but I believe that misses the point.

To help us understand the context behind the rule, Pike cites Frederick Brooks’ “The Mythical Man-Month” p. 102. Here it is for your edification:

Representation is the Essence of Programming

Beyond craftmanship lies invention, and it is here that lean, spare, fast programs are born. Almost always these are the result of strategic breakthrough rather than tactical cleverness. Sometimes the strategic breakthrough will be a new algorithm, such as the Cooley-Tukey Fast Fourier Transform or the substitution of an n log n sort for an n² set of comparisons.

Much more often, strategic breakthrough will come from redoing the representation of the data or tables. This is where the heart of your program lies. Show me your flowcharts and conceal your tables, and I shall be continued to be mystified. Show me your tables, and I won’t usually need your flowcharts; they’ll be obvious.

It is easy to multiply examples of the power of representations. I recall a young man undertaking to build an elaborate console interpreter for an IBM 650. He ended up packing it onto an incredibly small amount of space by building an interpreter for the interpreter, recognizing that human interactions are slow and infrequent, but space was dear. Digitek’s elegant little Fortran compiler uses a very dense, specialized representation for the compiler code itself, so that external storage is not needed. That time lost in decoding this representation is gained back tenfold by avoiding input-output. (The exercieses at the end of Chapter 6 in Brooks and Inversion, “Automatic Data Processing” include a collection of such examples, as do many of Knuth’s exercises.)

The programmer at wit’s end for lack of space can often do best by disentangling himself from his code, rearing back, and contemplating his data. Representation is the essence of programming

References:

Wikipedia: Unix_philosophy

Eric Steven Raymond: The Art of Unix Programming: Basics of the Unix Philosophy

40 year old ongoing study into preschool still providing insight

Posted on November 8, 2009 by Karl

American RadioWorks: Emily Hanford: Early Lessons: “doing well in school, and in life, is about more than a test score.”:

“Now you’re getting into something really deep,” says economist James Heckman. “How is it that motivation is affected? What causes motivation?”

Heckman is a Nobel laureate who teaches at the University of Chicago. Preschool was not among his interests until he came across the Perry Study several years ago. What caught his attention is the apparent paradox at its core: The people who went to preschool were not “smarter” than their peers, but they did better.

The assumption at the heart of a lot of economic theory is that measured intelligence is the key to everything. But with the Perry Preschool children, something else made the difference. It was not IQ. Heckman is now working with psychologists to try to understand how the preschool may have affected the development of what he calls “non-cognitive” skills, things like motivation, sociability and the ability to work with others.

These are critical skills that help people succeed at school, at work – and in life.

And as it turns out, the Perry preschool children did do better in life.

Profile of Ludwig Wittgenstein in Time Magazine

Posted on November 1, 2009 by Karl

Time Magazine: Ludwig Wittgenstein: He began by trying to reduce all mathematics to logic and ended by finding most metaphysics to be nonsense

Ludwig Wittgensten is a major character in Logicomix.

Economic Crisis related links for October 31st, 2009

Posted on October 31, 2009 by Karl

LA Independent: A one-man street team: Once one of Hollywood’s homeless, Mark Horvath turns his knack for storytelling into a personalized video chronicle of a national tragedy.: Through his experiences, he has come to realize that the only way to truly stop homelessness is by getting people off streets, and into homes and jobs.

NYTimes: Foreclosures Force Ex-Homeowners to Turn to Shelters: “So, as lean times endure and paychecks disappear, homeless shelters are absorbing those who have run out of alternatives.”

Homeless Resource Center: Fonfield-Ayinla, Gladys : My Experience Parenting While Homeless: It was never a goal of mine to be homeless, but it happened.

NYTimes: Recession Drives Surge in Youth Runaways : oreclosures, layoffs, rising food and fuel prices and inadequate supplies of low-cost housing have stretched families to the extreme, and those pressures have trickled down to teenagers and preteens.

NYTimes: For Runaways, Sex Buys Survival: Nearly a third of the children who flee or are kicked out of their homes each year engage in sex for food, drugs or a place to stay, according to a variety of studies published in academic and public health journals.

Internet life links for October 31, 2009

Posted on October 31, 2009 by Karl

Alex Hillman recently tweeted: “Twitter lists illustrate the most important shift in the internet: your bio is now written by others, and what they say about you.” He follows up with a longer piece on his blog.

Google Wave: we came, we saw, we played D&D: It’s easy to see why many people who use it for the first time wonder what the big deal is–as I said above, you really need to try to accomplish something with it as part of a group before you understand what it’s good for.

Rafe shares the frustration he has trying to correct the the misinformation friends and family are consuming off the Web and from cable news media.

I had my Twitter updates streaming to Facebook, but recently discontinued that. danah boyd shares some of the reasons in her blog post: Some thoughts on Twitter vs. Facebook Status Updates:

One way to really see this is when people on Twitter auto-update their Facebook (guilty as charged). The experiences and feedback on Twitter feel very different than the experiences and feedback on Facebook. On Twitter, I feel like I’m part of an ocean of people, catching certain waves and creating my own. Things whirl past and I add stuff to the mix. When I post the same messages to Facebook, I’m consistently shocked by the people who take the time to leave comments about them, to favorite them, to ask questions in response, to start a conversation. (Note: I’m terrible about using social media for conversation and so I’m a terrible respondent on Facebook.) Many of the people following me are the same, but the entire experience is different.

Seth Godin comments on the penalty you face exceeding the Dunbar Number

And finally, this is brilliant.

Will Bunch: “The day Philly stopped being a joke”

Posted on October 31, 2009 by Karl

Will Bunch: “The day Philly stopped being a joke”:

Everyone said the real problem was that Philadelphia — the nation’s sixth largest city and fourth largest TV market, birthplace of both the Declaration of Independence and the U.S. Constitution — was a victim of a strange condition: low civic self-esteem. And what brought that on? A lot of things, some of them self-inflicted like our “corrupt and content” political culture — but there was also a severe case of sibling jealousy, the sibling being our colonial cousin of New York City.

Even at the start of the 19th Century, Philadelphia was still the center of the nation’s culture and higher learning — and then the Industrial Revolution hit. Philly plunged right in, manufacturing everything under the sun, from steam locomotives to Stetson hats. New York decided instead to manage — and occasionally gamble — the profits. You know how that worked out (when was the last time you wore a Stetson hat — or were transported by a steam locomotive?) Just 100 miles to the northeast, New York became a black-hole-like force, sucking the energy from Philadelphia, stealing everything from our talented college grads to foreign tourists who never even saw the nation’s founding city as they whizzed down the New Jersey Turnpike from the Statue of Liberty to the Washington Monument. New York got Broadway, the UN, the World’s Fair…and baseball. The Yankees won more World Series’ than any other team, while the Phillies lost more games than any other franchise in America — in any sport. Even the Mets, who didn’t exist until 1962, won a World Series before the Phillies finally did in 1980.

Bad behavior became the mask for a city’s collective anxiety. It wasn’t just the notorious 700 Level at the dank, concrete Veterans Stadium, where wearing an opponent’s jersey meant maybe sparing your life…maybe. Here at the Philadelphia Daily News, back when the Eagles became title contenders (but nothing more, of course) in the 2000s, we had a regular feature that inside the newsroom was officially known as “hater’s guides” to the cities that the Eagles were playing that week, even if the “city” was actually a Wisconsin Nice burg like Green Bay. You didn’t need Sigmund Freud to diagnose the pathology of Philly’s “haters guides.”

Then there was a day when everything seemed to change.

Read the whole thing. It’s fantastic.