The Physics of Information Technology (Hardcover)

by Neil Gershenfeld (Author) "Why does computation require energy?..." (more)
Key Phrases: ray matrices, ray matrix, fundamental physical limits, New York, Central Limit Theorem, Ohm's Law (more...)

Editorial Reviews

Review
"...throughout the text, Gershenfeld retains much of the conversational tone and spontaneity of a lecture. At its best, this makes for enjoyable reading, with interesting tidbits and asides that enliven the discussions....Gershenfeld's book will be valuable for physical scientists looking for an enjoyable introduction to the information sciences. And anyone wishing to learn more about diverse areas of physics related to information technology will find it of interest." Science, Nov. 01

"Gershenfeld's book will be valuable for physical scientists looking for an enjoyable introduction to the information sciences. And anyone wishing to learn more about diverse areas of physics related to information technology will find it of interest. Science Nov 2001

Product Description
The Physics of Information Technology explores the familiar devices that we use to collect, transform, transmit, and interact with electronic information. Many such devices operate surprisingly close to very many fundamental physical limits. Understanding how such devices work, and how they can (and cannot) be improved, requires deep insight into the character of physical law as well as engineering practice. The book starts with an introduction to units, forces, and the probabilistic foundations of noise and signaling, then progresses through the electromagnetics of wired and wireless communications, and the quantum mechanics of electronic, optical, and magnetic materials, to discussions of mechanisms for computation, storage, sensing, and display. This self-contained volume will help both physical scientists and computer scientists see beyond the conventional division between hardware and software to understand the implications of physical theory for information manipulation.

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Product Details

• Hardcover: 370 pages
• Publisher: Cambridge University Press; 1 edition (January 15, 2000)
• Language: English
• ISBN-10: 0521580447
• ISBN-13: 978-0521580441
• Product Dimensions: 9.8 x 6.9 x 1 inches
• Shipping Weight: 1.9 pounds (View shipping rates and policies)
• Average Customer Review: 4.2 out of 5 stars See all reviews (5 customer reviews)
• Amazon.com Sales Rank: #861,435 in Books (See Bestsellers in Books)

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Customer Reviews

Most Helpful Customer Reviews

46 of 53 people found the following review helpful:

2.0 out of 5 stars Great idea but marred by many, many errors, May 31, 2001

By	"engphys" (Yorktown Heights, NY) - See all my reviews

When I first saw this book advertised, I thought it would be a painless way to fill in the gaps in my knowledge, e.g. in quantum computing and information theory. It indeed has a very wide sweep, an engaging style that is very clear and moves the reader along, an attractive design, and many other good points. I haven't checked all the math, but Gershenfeld seems most at home with theory.

The problem is that when he touches on something I really am expert in, he falls on his face much too often. I don't mean just that he oversimplifies and leaves things out--how could he not--but that the book is full of genuine factual misinformation. Some representative examples: In 3.1.2, he confuses deterministic and stochastic processes completely, a confusion that persists throughout the extended discussion of noise; in 3.3.1, he says that shot noise dominates only for small arrival rates, whereas in reality it is dominant only in the limit of large rates; in 10.3, he's wrong about how bipolar transistors work, and wrongly says that their base current is why they aren't widely used in logic anymore; in the preamble to Chapter 12, he says that hard disk drives use "basically rust" to store information, whereas they've used plated metal for years, and that recording heads fly at 1 micron, whereas it's 50-100 times closer than that (120-200 angstroms). His discussion of modems wrongly says that 50kb/s+ modems rely on data compression for their speed, whereas the discrepancy is his underestimation of the S/N ratio of a good phone line.

And (most embarrassing of all for a theoretician) in his discussion of special relativity, he goes through a long derivation of the kinetic energy of motion, but makes an elementary integration error in the last line in order to (wrongly) display the famous mc**2.

Gershenfeld is clearly a very able guy who knows a lot about the physics of information technology--but I'd trust the book a lot more if I didn't keep tripping over these sorts of things. Let's hope the second edition is more carefully done.

16 of 18 people found the following review helpful:

5.0 out of 5 stars Setting things straight, September 15, 2004

By	A reader (Berkeley, CA) - See all my reviews

I read this book shortly after it was published and continue to refer to it often, particularly for its insight discussion about noise. I was shocked to see the overwhelming percentage of helpful votes for the June 1, 2001 review and feel compelled to set things straight:

The author's derivation of E = mc**2, in which he includes the factor of \gamma, is absolutely correct. The previous reviewer has apparently confused rest energy and total energy.

The author never claims that the fly height of modern hard disk heads is one micron; he only points out that, because the bit spacing is on the order of a micron, the head must fly at least that close to the disk. Neither does the author say that modern hard disks actually use rust to store information.

You get the picture. This is an excellent text which covers a wide range of topics clearly and accurately, although it can be challenging for those without a good undergraduate background in physics or engineering.

7 of 8 people found the following review helpful:

5.0 out of 5 stars Great book, but not a *light* read, November 20, 2004

By	D. Levy "student of the world" - See all my reviews (REAL NAME)

This book is cram packed with information, However at a cost. There are some thing that are assumed that you already know. If you are rusty, you may have to look at other sources. Example p is a variable for momentum = m*v ( kinda simple, but missing, p is used with no definition in ch 2). Also the book is not error free, but I've only found 1 error so far( in the proof of the Equipartition theorem with B = kT instead of B = (kT)^-1) which drove me crazy for 1 hour untill I looked at other source.( and how many technical books are error free?), but a findable errata would be nice. On the whole, if you have a clue and really want to see all the considerations, it's a great book