A major addition to the tools is a <em>race detector</em>, a way to find
bugs in programs caused by problems like concurrent changes to the same variable.
This new facility is built into the <code>go</code> tool.
+For now, it is only available on Linux, Mac OS X, and Windows systems with
+64-bit x86 processors.
To enable it, set the <code>-race</code> flag when building or testing your program
(for instance, <code>go test -race</code>).
The race detector is documented in <a href="/doc/articles/race_detector.html">a separate article</a>.