The Little Book of Semaphores is a free (in both senses of the word) textbook that introduces the principles of synchronization for concurrent programming.
In most computer science curricula, synchronization is a module in an Operating Systems class. OS textbooks present a standard set of problems with a standard set of solutions, but most students don't get a good understanding of the material or the ability to solve similar problems.
The approach of this book is to identify patterns that are useful for a variety of synchronization problems and then show how they can be assembled into solutions. After each problem, the book offers a hint before showing a solution, giving students a better chance of discovering solutions on their own.
The book covers the classical problems, including "Readers-writers", "Producer-consumer", and "Dining Philosophers". In addition, it collects a number of not-so-classical problems, some written by the author and some by other teachers and textbook writers. Readers are invited to create and submit new problems.
Penrose is a java-based virtual directory server. Virtual directory enables federating (aggregating) identity data from multiple heterogeneous sources like directory, databases, flat files, and web services - real-time - and makes it available to identity consumers via LDAP.
Fog Creek Joel Spolsky has never been one to hide his opinions. Since 2000, he has developed a loyal following for his insightful, tell-it-like-it-is essays on software development and management on his popular Weblog "Joel on Software" (http://www.joelo