Product Description

Computers are incredible. They are one of the most important inventions of the 20th century, dramatically and irrevocably changing the way we live. That is the good news. The bad news is that there are still major limitations to computers, serious problems that not even the most powerful computers can solve. The consequences of such limitations can be serious. Too often these limits get overlooked, in the quest for bigger, better, and more powerful computers. In Computers Ltd., David Harel, best-selling author of Algorithmics, explains and illustrates one of the most fundamental, yet under-exposed facets of computers - their inherent limitations. Looking at the bad news that is proven, lasting and robust, discussing limitations that no amounts of hardware, software, talents or resources can overcome, the book presents a disturbing and provocative view of computing at the start of the 21st century. Along the way he shows just how far from perfect computers are, while shattering some of the many claims made for these machines. Though we may strive for bigger and better things in computing, we need to be realistic: computers are not omnipotent - far from it. Moreover, the problem is real and here to stay.

Product Details

• Amazon Sales Rank: #405550 in Books
• Published on: 2003-09-25
• Original language: English
• Number of items: 1
• Binding: Paperback
• 240 pages

About the Author
David Harel is the Dean of the Faculty of Mathematics and Computer Science at the Weizmann Institute of Science in Israel, and is incumbent of the William Sussman Professional Chair. He is a highly respected computer scientist who has carried out research in many areas of computer science. He has received a number of awards, including ACM's Karlstrom Outstanding Educator Award in 1992, and the 1997 Israeli Prime Minister's Award for Software. His book, Algorithmics: The Spirit of
Computing (Addison-Wesley, 1987, 2nd. edn. 1992) was the Spring 1988 Main Selection of the Macmillan Library of Science. He is a Fellow of the AMC and of the IEEE.

Customer Reviews

A limited introduction to the limits of Computation
This another nice book from David Harel, the author of the delightful
'Algorithmics : the spirit of Computer Science', which introduces the
general reader to the limits of computation (and hence the limits of
what computers can do).

Harel, who's a renowned figure in the field of Theoretical Computer Science,
has the ability to write and explain in a way that makes things seem
wonderfully clear, and indeed it is only such authors who can write good
books for the general reader.

This small (240 pages) book is quite ambitious in its coverage of topics -
starting off with the notion of an algorithm, it goes on to discuss
Efficiency and correctness, Turing machines, Finite state machines,
Decidability, Computability, Complexity, NP-completeness, Recursion,
Parallel algorithms, Probabilistic algorithms, and even touches upon
Quantum Computing and Artificial Intelligence !!

All this is done with almost no mathematics, at least hardly any beyond
high-school level. The reader is gently introduced to some of the most
celebrated problems of Computer Science, and he/she can get a feel of
the nature of this exciting and interesting field.

Throughout the book, the author keeps underscoring the fact that no matter
how far technology progresses, there'll always be problems that we can't
solve cheaply, or can't solve at all, or can't ever know whether they
can be solved or not (!!), ie he stresses that there are problems that
are 'beyond computers', which cannot be tamed by more and more processing
power or any other technological advancements.

This book covers pretty much the same range of topics as Harel's earlier
book, 'Algorithmics : the spirit of Computer Science', but in only half
the number of pages, and with a heavy emphasis on the 'limitations' of
computers, which actually are limitations of our knowledge rather than
of the machines themselves.

How does it compare with the eariler book ? Well, it's more uptodate,
since it was published in 2000, whereas the other one was in 1992 -
so here you find buzzwords like 'Java', 'Dotcom', 'Quantum Computing',
etc, which you wouldn't find in the earlier book, but on the whole
i prefer the earlier one, since it had a little more detail, made you
think a little more, and even had exercises for those who were interested
in probing further.

So all in all, if you want a light, breezy introduction to the basic ideas
of Theoretical Computer Science which doesn't demand too much concentration,
this is a good choice, but if you're willing to put in some time & effort
& enjoy puzzles & logical thinking, then you'll find Harel's other book,
'Algorithmics : the spirit of Computer Science' much more rewarding.

Does the author have a vendetta against computers?
Does the author have a vendetta against computers or something? The first few chapters slag off computers a great deal saying they can't do this, or they can't do that. Just because you can't work out the answer for something yourself (albeit a human) doesn't mean you can pass it off as being a computer problem/ error, but put more precisely something 'They really can't do' (as the title states). Some of the points made in the book will never be solved by a human let alone a computer.

But the book does make you think, and opens your mind to various other topics that you would never really bring into consideration when thinking about computers.

Interesting but repetitive
Harel presented an interesting case against computers, but he just seemed to be driving one or two points home too much. Yes, we KNOW computers are serial and that some tasks take ages. Yet it the current paradigm of computing is rapidly shifting (parallel, quantum, molecular...) and while he does briefly address these, I don't think enough emphasis is given to quite how important non-computable issues are. At the moment, cryptography is non-computable (well, not true - but very hard) and quantum computing will theoritically destroy that...etc.

I don't mean to dismiss this book - it does have some very interesting points, thoughts and ideas and the title of the books obviously suggests that it should look at the BAD points of computers as opposed to the good, but a more open approach could have been taken.