improve wording

Author: vladak

synchro.tex

@@ -93,8 +93,8 @@
 \end{enumerate}
 \item Note that synchronization problems may surface only after the program is
 run on multiprocessor(core) machine or on more processors than what is used when
-development.  However, given that nowadays you have a few CPUs even on a
-low-level laptop, it is easier to test such scenarios than in the past.
+development.  Given that nowadays even a low-level laptop has multiple CPU
+cores, it is easier to test such scenarios than in the past.
 \end{itemize}
 
 %%%%%
@@ -252,7 +252,7 @@
 Peterson solution, e.g. on Wikipedia.
 \item We are not going to deal with theoretical algorithms or compare hardware
 mechanisms used by the kernel. Instead we are going to focus on the use of
-file level locking (which use the atomicity of some file operations)
+file level locking (which builds on the atomicity of some file operations)
 and special synchronization primitives offered by the kernel.
 \item note that ``signalling'' here has nothing to do with Unix signals.  It's
 confusing though.