Merge pull request #133 from kbara/master

Added 'Practical File System Design: The Be File System' and a Smalltalk list.

free-programming-books.md

@@ -93,7 +93,7 @@
 * [TechBooksForFree.com](http://www.techbooksforfree.com/)
 * [Theassayer.org](http://theassayer.org/)
 * [Wikibooks: Programming](http://en.wikibooks.org/wiki/Category%3aComputer_programming)
-
+* [Free Smalltalk Books, collected by Stéphane Ducasse](http://stephane.ducasse.free.fr/FreeBooks.html)
 
 ###Graphics Programming
 
@@ -152,6 +152,7 @@
 * [The Art of Unix Programming](http://catb.org/esr/writings/taoup/html/)
 * [The Little Book of Semaphores](http://greenteapress.com/semaphores/) - Allen B. Downey
 * [Operating Systems and Middleware](https://gustavus.edu/mcs/max/os-book/) (PDF and LaTeX)
+* [Practical File System Design:The Be File System](http://www.nobius.org/~dbg/practical-file-system-design.pdf)(PDF) - Dominic Giampaolo
 
 ####Database
 * [Database Fundamentals](http://public.dhe.ibm.com/software/dw/db2/express-c/wiki/Database_fundamentals.pdf) (PDF)