If you have MacOS 10.3 or 10.4 and you would like to use Python
scripts such as @command{convert-ly} and @command{lilypond-book}, see
-@ref{Setup for MacOS X}.
+@ref{Setup for MacOS X,,,lilypond-program,Application Usage}.
@node Compiling from source
@knownissues
-@code{-j} command-line option of @command{make} is unsupported for
-building the documentation. As the most time consuming task is
-running LilyPond to build images of music, the makefile variable
-@code{CPU_COUNT} may be set in @file{local.make} or on the command line
-to the number of @code{.ly} files that LilyPond should process
-simultaneously, e.g. on a bi-processor or dual core machine
+The most time consuming task for building the documentation is running
+LilyPond to build images of music, and there cannot be several
+simultaneously running @command{lilypond-book} instances, so @code{-j}
+@command{make} option does not significantly speed up the build process.
+To help speed it up, the makefile variable @var{CPU_COUNT} may be set
+in @file{local.make} or on the command line to the number of
+@code{.ly} files that LilyPond should process simultaneously, e.g. on
+a bi-processor or dual core machine
@example
-make CPU_COUNT=2 web
+make -j3 CPU_COUNT=3 web
@end example
+@noindent
+The recommended value of @var{CPU_COUNT} is one plus the number of
+cores or processors, but it is advisable to set it to a smaller value
+if your system has not enough RAM to run that many simultaneous
+LilyPond instances.
+
If source files have changed since last documentation build, output
files that need to be rebuilt are normally rebuilt, even if you do not
run @code{make web-clean} first. However, building dependencies in the