--- a/doc/testing/background.texi	Sun Apr 11 16:32:13 2010 -0700
+++ b/doc/testing/background.texi	Mon Apr 12 16:33:17 2010 +0400
@@ -33,7 +33,7 @@
 
 There are also a number of different philosophical approaches to software 
 testing.  For example, some organizations advocate writing test programs
-before actually imlementing the desired software, yielding ``test-driven 
+before actually implementing the desired software, yielding ``test-driven 
 development.''  Some organizations advocate testing from a customer perspective
 as soon as possible, following a parallel with the agile development process:
 ``test early and test often.''  This is sometimes called ``agile testing.''  It
@@ -92,7 +92,7 @@
 
 Once this is done, one can develop an abstract model of the target system.  This
 is typically an exercise in managing the tradeoffs between complexity, resource
-requiremens and accuracy.  The process of developing an abstract model has been
+requirements and accuracy.  The process of developing an abstract model has been
 called @emph{model qualification} in the literature.  In the case of a TCP 
 protocol, this process results in a design for a collection of objects, 
 interactions and behaviors that will fully implement RFC 793 in @command{ns-3}.
@@ -140,7 +140,7 @@
 testing is called ``stress testing.''
 
 The system and its components may be exposed to so-called ``clean tests'' that
-demostrate a positive result -- that is that the system operates correctly in 
+demonstrate a positive result -- that is that the system operates correctly in 
 response to a large variation of expected configurations.  
 
 The system and its components may also be exposed to ``dirty tests'' which 
@@ -203,7 +203,7 @@
 in practice.
 
 A @emph{local regression} is one in which a change affects the changed component
-directy.  For example, if a component is modified to allocate and free memory
+directly.  For example, if a component is modified to allocate and free memory
 but stale pointers are used, the component itself fails.
 
 A @emph{remote regression} is one in which a change to one component breaks