Lions' Commentary on Unix

Rating:
Summary: The Way
Review: Any comments made on a superlative commentary on superb code would be largely superfluous. This gem should be part of any Operating Systems course. The greatest of the pleasures offered by the book is the opportunity to read the source code, version 6 of the UNIX Operating System. It is a unique opportunity to see the real masters at work!

Highly recommended, with Maurice J Bach's "The Design of the Unix Operating System" as a supplement.

Rating:
Summary: Awesome book
Review: I had always wanted to lay my hands on this manual. Its fantastic. Admitted that the PDP is outdated and all but the core concepts for the OS still remain the same. Also I got to look at some really tight code from the Masters themselves. The book is worth every penny. I would definitely recommend it to someone who has a *healthy* curiosity to look under the hood to see how UNIX actually looks like.

Rating:
Summary: Amazing and insightful historical perspective
Review: I learned about the existence of this manuscript 16 years ago, yet could never find a full version, until the book came. I have read most of it and it is beatiful. Many of the tradeoffs the early UNIX versions had are there. Context switching is done via coroutine jumps, the callout table is used only for the teletype, the very origins of the scheduler and swapper are neatly explained among many other things. PDP11 architecture is simple enough to make this book still a jewel for those interested in learning OS concepts and evolution and specifically UNIX.

Rating:
Summary: The book for Unix kernel geeks
Review: The Lions Book was illegally pirated for many years after its publication, with fifth-generation photocopies being the most prized possessions of many Unix kernel hackers.

It was republished shortly after the author died when the politics of the ownership of the Unix sources settled down.

So what's so special about the book?

The first reason is that John Lions believed strongly that just as in literature, where being able to read and analyse great works is more likely to lead to being able to write comparable works, software designers should learn to read and criticise working code. He chose Unix, 6th edition, running on the PDP-11. His book is a subset of the kernel sources, with commentary.

The second reason is that the code itself is, in general, pretty fine stuff. It includes the legendary comment /* you are not expected to understand this */. It's amazing that so much of modern Unix functionality already existed in the mid-70s and ran in only 32kbytes of RAM.

And thirdly, it's a historical document that describes a real operating system, that's come to effect the development of most subsequent system software.

It's a great read, if you're a geek, and you suspect that good code, like good literature should be read and enjoyed.

Rating:
Summary: Greatest OS Introduction
Review: This book is a true computer science classic and will never go out of print. It is the greatest introduction to operating systems there is. I lived for years with a 5th generation photocopy and i am very glad to own a new, clear copy.

Buy it, study it, learn... give it to your children.

Rating:
Summary: Beautiful
Review: This is prably the best source/commentary book. Though some of the stuff is outdated, the core still is quite valid and gives useful insight into the implementation of the kernel.

I have gone through about 10-15% of the book, like filesystems and os initialization, and fouud it extremely helpful.

santy

Rating:
Summary: Elegant and Inspiring
Review: This is the kind of computer book which makes me wish all my friends were programmers so I could share it with everyone I know.

Although the version of Unix it documents is wildly out of date and the C code would make a K&R compiler laugh in disbelief, the underlying elegance of the code shines through. The commentary is brilliant -- Lions pushes the reader to understand for him or herself, all the while providing clear guidance through the most complicated pieces.

Having programmed for years, I've never fully understood such deep mysteries as how process switching works, or how the OS bootstraps itself. Although I am sure that things are much more complex today, having read and pored over this old text and having achieved that elusive feeling of enlightenment, I now feel that it all makes sense.

My only complaint is that they should have printed it as two volumes as it was originally produced. Constantly flipping back and forth was frustrating. But other than that, a total pleasure.