Understanding the Digital World, Brian Kernighan
Understanding the Digital World, Brian W. Kernighan ( Princeton University Press, 256pp, $49.99)
It’s not a bad endorsement to have Google chairman Eric Schmidt say of your book “Everyone on Earth needs to read it.” I certainly needed to. Brian Kernighan, a professor of computer science at Princeton University in the US, has produced an elegant, authoritative and surprisingly witty guide to the modern landscape of computers and the internet, and the attendant issues of privacy, cryptography and security.
Understanding the Digital World
The joy is he assumes no prior knowledge and so delivers succinct explanations of all the basics you – okay, I – have pretended to know about but never quite understood. The book’s three sections – hardware, software and communications – are based on a course Kernighan has taught non-technical students at Princeton for almost 20 years.
The hardware section looks at what’s inside a computer, how it’s built, how it works, how it stores information. What are bits and bytes, and how are they turned into music and pictures? There are clear descriptions of CPU, RAM, logic gates, integrated circuits, transistors, and all the other magic that allows us to manufacture chips with wiring as small as 14 millionths of a millimetre thick.
The chapters on software and programming are compelling, despite Kernighan’s cheerful declaration that “you don’t need to follow all the details or the occasional formulas” as he leads the reader into some technical forests. Just as the concepts of quantum physics excite the imagination of many who couldn’t solve the simplest of that discipline’s equations, so too the mind-boggling complexity of creating algorithms, in a language that can tolerate no mistakes, intrigues someone who has trouble setting his alarm clock.
Kernighan begins with linear algorithms, covers sorting, then moves on to “hard problems”, all the while explaining them with real-world analogies and a lightness of touch – some complex areas are, he says, “so esoteric that only specialists could care about them”. He looks at operating systems and file systems and where information goes when you delete it. Answer: nowhere. It stays on your computer until the blocks of memory that host it are overwritten, and even then it might be accessible to military-grade file extraction. It’s best to physically destroy your hard disk, Kernighan says, adding ominously that even that might not be enough if your work is being backed up to a network system or to the cloud.
If that sounds faintly paranoid, the section on communications gives good reason to wonder whether there is still any such thing as privacy. From the original Marathon runner, Pheidippides, through pony express riders and France’s optical telegraph system – which could relay visual signals made by giant mechanical arms from tower to tower (Paris to Lille, 230km, in 10 minutes) – to the modern cellphone, people have always sought to transmit information quickly over long distances. And other people have always sought to know what those messages said.
As Kernighan examines the various networks that connect us, amid the challenges of bandwidth and delay, “lossless” and “lossy” compression, error detection and correction, he reveals the weak spots for security. Wireless, as he points out, is a broadcast medium, which means that anyone in range can listen in. Suffice to say no one who reads this book will do their internet banking in a big-brand coffee shop again.
The internet, of course, through its most visible face, the World Wide Web, is where most of us bump up against the digital world. The history of this “packet network” is short but fascinating. Kernighan tracks the bursts of development that have given us IP and TCP, DNS and NAT, SMTP and HTTP, and now the Internet of Things. From nothing in 1990, the Web has become an essential part of modern life.
But alongside its benefits are problems and risks, says Kernighan, “because it enables action at a distance – we are visible and vulnerable to faraway people we have never met”.
Some of those people are benign; some, including governments, less so. Kernighan traces in alarming detail the “arms race between attackers and defenders”: the fraud, the “phishing”, the identity theft, and the more sinister aggregation of personal information through various points of leakage and infiltration. He also, happily, gives a masterclass in how to protect your data from those attackers. “If you care about your personal privacy and online security,” says Kernighan, “it’s imperative to be more tech-savvy than most people are.”
The joy is he assumes no prior knowledge and so delivers succinct explanations of all the basics you – okay, I – have pretended to know about but never quite understood. The book’s three sections – hardware, software and communications – are based on a course Kernighan has taught non-technical students at Princeton for almost 20 years.
The hardware section looks at what’s inside a computer, how it’s built, how it works, how it stores information. What are bits and bytes, and how are they turned into music and pictures? There are clear descriptions of CPU, RAM, logic gates, integrated circuits, transistors, and all the other magic that allows us to manufacture chips with wiring as small as 14 millionths of a millimetre thick.
The chapters on software and programming are compelling, despite Kernighan’s cheerful declaration that “you don’t need to follow all the details or the occasional formulas” as he leads the reader into some technical forests. Just as the concepts of quantum physics excite the imagination of many who couldn’t solve the simplest of that discipline’s equations, so too the mind-boggling complexity of creating algorithms, in a language that can tolerate no mistakes, intrigues someone who has trouble setting his alarm clock.
Kernighan begins with linear algorithms, covers sorting, then moves on to “hard problems”, all the while explaining them with real-world analogies and a lightness of touch – some complex areas are, he says, “so esoteric that only specialists could care about them”. He looks at operating systems and file systems and where information goes when you delete it. Answer: nowhere. It stays on your computer until the blocks of memory that host it are overwritten, and even then it might be accessible to military-grade file extraction. It’s best to physically destroy your hard disk, Kernighan says, adding ominously that even that might not be enough if your work is being backed up to a network system or to the cloud.
If that sounds faintly paranoid, the section on communications gives good reason to wonder whether there is still any such thing as privacy. From the original Marathon runner, Pheidippides, through pony express riders and France’s optical telegraph system – which could relay visual signals made by giant mechanical arms from tower to tower (Paris to Lille, 230km, in 10 minutes) – to the modern cellphone, people have always sought to transmit information quickly over long distances. And other people have always sought to know what those messages said.
As Kernighan examines the various networks that connect us, amid the challenges of bandwidth and delay, “lossless” and “lossy” compression, error detection and correction, he reveals the weak spots for security. Wireless, as he points out, is a broadcast medium, which means that anyone in range can listen in. Suffice to say no one who reads this book will do their internet banking in a big-brand coffee shop again.
The internet, of course, through its most visible face, the World Wide Web, is where most of us bump up against the digital world. The history of this “packet network” is short but fascinating. Kernighan tracks the bursts of development that have given us IP and TCP, DNS and NAT, SMTP and HTTP, and now the Internet of Things. From nothing in 1990, the Web has become an essential part of modern life.
But alongside its benefits are problems and risks, says Kernighan, “because it enables action at a distance – we are visible and vulnerable to faraway people we have never met”.
Some of those people are benign; some, including governments, less so. Kernighan traces in alarming detail the “arms race between attackers and defenders”: the fraud, the “phishing”, the identity theft, and the more sinister aggregation of personal information through various points of leakage and infiltration. He also, happily, gives a masterclass in how to protect your data from those attackers. “If you care about your personal privacy and online security,” says Kernighan, “it’s imperative to be more tech-savvy than most people are.”
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