1 files changed, 21 insertions, 0 deletions
diff --git a/Lib/asyncore.py b/Lib/asyncore.py
index 07b9fc3..8e11d76 100644
--- a/Lib/asyncore.py
+++ b/Lib/asyncore.py
@@ -25,6 +25,27 @@
 # CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 # ======================================================================
 
+"""Basic infrastructure for asynchronous socket service clients and servers.
+
+There are only two ways to have a program on a single processor do "more
+than one thing at a time".  Multi-threaded programming is the simplest and 
+most popular way to do it, but there is another very different technique,
+that lets you have nearly all the advantages of multi-threading, without
+actually using multiple threads. it's really only practical if your program
+is largely I/O bound. If your program is CPU bound, then pre-emptive
+scheduled threads are probably what you really need. Network servers are
+rarely CPU-bound, however. 
+
+If your operating system supports the select() system call in its I/O 
+library (and nearly all do), then you can use it to juggle multiple
+communication channels at once; doing other work while your I/O is taking
+place in the "background."  Although this strategy can seem strange and
+complex, especially at first, it is in many ways easier to understand and
+control than multi-threaded programming. The module documented here solves
+many of the difficult problems for you, making the task of building
+sophisticated high-performance network servers and clients a snap. 
+"""
+
 import select
 import socket
 import string