“Absolutely amazing! A page turner, just like Harry Potter for the technically minded.” —Tobias Svensson from review at return 42;

“This book is so interesting I did 60 minutes on the treadmill yesterday instead of the usual 30 because I couldn’t stop reading.” —Joel Spolsky on Joel on Software

“Coders at Work should inspire readers to learn about the wider context of their craft and stop the reinvention of the proverbial wheel” —Vladimir Sedach from review at Slashdot

“Peter Seibel asks the sort of questions only a fellow programmer would ask. Reading this book may be the next best thing to chatting with these illustrious programmers in person.” —Ehud Lamm, Founder of Lambda the Ultimate - the programming languages weblog

“I highly recommend it.” —Andy Mulholland, CTO, Capgemini

“I have long known the names and of the work of about half of the programmers in Peter Seibel’s wonderful book, Coders at Work; and it is fascinating to read their ideas about their lives and their ideas about programming. Better yet, I have now learned about the lives and philosophies of the other half of the programmers in the book, whose systems were known to me but the programmers themselves were not. Anyone interested in computer programming and what makes a great computer programmer will enjoy this book.” —Dave Walden, original member of the BBN ARPANET team

“These are wonderful interviews and this looks to be a bible for any programmer who aspires to be better.” —Peter Christensen, Founder of GeekStack.com

“This book is dead sexy. When it comes out, you should definitely get a copy.” —Joseph F. Miklojcik III from review at jfm3> _

“Superb book!” —Prakash Swaminathan from review at CloudKnow

“Read it, because then you will know the greatest coding brains.” —Amit Shaw from review at Teleported Bits

“One of the other core questions Peter asks is, what books would you recommend to help a developer learn programming? For me, this book joins my short list—it takes you away from the limitations of learning within a single company or community, and shows you the breadth of experiences that can make someone a great developer.” —Marc Hedlund from review at O’Reilly Radar

“The range of topics covered is just astounding.” —Chris Hartjes from review at @TheKeyboard

Bernie Cosell

In 1969 when the first two nodes of the ARPANET—the network that would become the core of the Internet—came on line, every packet that flowed over 50 kilobit/second leased lines was routed through two specialized computers called Interface Message Processors, or IMPs. The IMPs were designed and built by Bolt Beranek and Newman (BBN), and the software that ran the IMPs had been written by a team of three programmers, one of whom was Bernie Cosell, who had left MIT three years before, at the beginning of his junior year, to join BBN.

Originally hired as an application programmer on a project building one of the earliest timesharing systems, Cosell quickly moved to the systems programming side of things and was soon “czar of the PDP-1 timesharing system” responsible for finishing the operating-system code and keeping the system running.

Over a 26-year career at BBN, Cosell would work on a little bit of everything, earning a reputation within BBN as a master debugger and “fixer” who could be thrown onto a struggling project to make the software work. And he hacked just for fun: to hone his Lisp skills he wrote DOCTOR, a version of Joseph Weizenbaum’s ELIZA, based on Weizenbaum’s description in a journal article. Written in BBN-LISP, which spread around the ARPANET along with the TENEX operating system, Cosell’s version of DOCTOR also had a wide distribution—wider than Weizenbaum’s original—inspiring new implementations and related programs.

In 1991 Cosell left BBN and bought a sheep farm in Virginia, where he now lives with his wife Lynn, three dogs, innumerable cats, and lots of sheep. He does some programming for a local ISP, hacks a bit on his own projects, and teaches a few courses in programming and computer security but is glad he no longer works as a full-time programmer. Ironically, as a result of his move to the country, Cosell—one of the fathers of the Internet—now has only dial-up access from his home.

In this interview we talked about how he won his reputation as a master debugger, the importance of writing clear code, and how he convinced the other programmers on the IMP project to stop patching the binary.