"Working with Unix Processes" Review (By Jesse Storimer)

23 Jul 2012 The last thing I want to do is dealing with low-level operating system things. That's one of the reasons why I like Ruby, because it keeps me from having to deal with all that. So why the hell would I read "Working with Unix Processes"? Well, first, it was the book of choice for the (fantastic) Ruby Rogues podcast, episode 058. And second: It was a really amazing ride! Jesse managed to get down to the lowest level and still managed to explain everything in terms I actually understand! You can get the book on Amazon for around 17.00€ ($21.00). Side note: "Working with Unix Processes" was first self published by Jesse Storimer over at workingwithunixprocesses.com, but has now been picked up by The Pragmatic Programmers.

Content

Working with Unix Processes concentrates on the rarely used Ruby module Kernel#fork and its companions. Jesse Storimer starts out with a gentle introduction to processes, process IDs and everything else you didn't know you wanted to know about processes. Did you know, for example, that processes belong to a process group? And that a whole process group can be killed at the same time? And that that's basically how a terminal emulator works? No? Neither did I! After he explains everything about processes, he goes on and explains that processes can fork. This is actually a very important feature of all operating system. All processes are spawned from one process, which is created at boot. And so he introduces us to process parents, children, and orphaned processes, and what that means. After forking, the next important thing is joining processes together again (for example to enable multicore processing). Of course, now that we have multiple processes, another important aspect is communication between processes. This is done either through signals or interprocess communication. He then ends "Working with Unix Processes" with an extensive Appendix, where he digs deeper into the inner workings of such gems as Resque or Unicorn.

The good

One part I loved about the book is that each chapter has a short note on "Use in the real world". Here Jesse Storimer highlights projects that use the aforementioned technique. Another nice thing he did was include a Spyglass server. This is a heavily documented server in Ruby that he developed specifically for the book, to highlight how his techniques can be leveraged. Reading through it is pure joy! A very nice feature of the book is that it is a living book. Since Jesse released it (Dec 20, 2011) he released 14 new version (some just fix typos, but others added full new chapters or new and extended explanations for the things he explained.

The bad

For one, the name. It is called "Working with Unix Processes", but a better name would have been "Working with Unix Processes in Ruby". A lot of the advise he gives is very Ruby specific, and all examples are in Ruby. I'm not saying it isn't applicable if you use other languages, but this book focuses on Ruby. Of course, this was the audience he had in mind, but it is something that everyone should remember when buying this book. I am also not sure what the target audience for the book is. A system programmer (which doesn't know Ruby) doesn't need to be told how fork works, or what process IDs are. For a Ruby programmer that just tries to leverage some more programming near the system, the book was a bit too terse, and the examples were too abstract.

Conclusion

Besides its shortcoming, I found it a great book to read. You can read it in 3 hours (aka a rainy Sunday afternoon) and get through it pretty quickly. If you want to dive deeper, the source code to Spyglass and the other mentioned open source projects are right at your fingertips. I recommend this book to everyone who is interested in a more systems programming approach, and wants to know the basics so he can see when they could help. Ruby knowledge is required though, or else the book won't make that much sense. The topic sounds boring, mundane even, but I think if you are at least a bit curious you should give it a chance and read it. Sparked your interest? Then don' wait and get the book! If you liked this post, you should follow me on Twitter and signup for the RSS feed!