Requirements:
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* Linux 2.6.x
* GHC 6.5
* libaio --- the Linux Asynchonrous I/O Library.
* libipq --- the iptables development library (iptables-dev in Debian)

  If you wish to try the web server, make sure that the HTML files are
  on one of these file systems: ext2, ext3, jfs, xfs.  Otherwise, AIO
  may not work.

Files and directories:
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IOLib/      : Low-level asynchronous I/O library
    Chunk.hs     : A type-safe representation of memory buffers
    AIO.hs       : FFI wrappers for the Linux AIO library
    Epoll.hs     : FFI wrappers for the Linux epoll interface
    NBIO.hs      : FFI wrappers for some non-blocking socket primitives
    PacketIO.hs  : FFI wrappers for sending/receiving IP packets.
    TCP.hs       : A proof-of-concept, purely functional TCP stack.

ThreadLib/  : The application-level thread library
    Thread.hs    : CPS Monad and system calls.
    Workers.hs   : Some standard and reusable event loops for constructing 
                   application-level schedulers.
                   A default scheduler implementation is also provided.
    FileIO.hs    : Synchronous disk library, implemented using Linux AIO
    SockIO.hs    : Synchronous socket library, implemented using standard 
                   non-blocking sockets with epoll.
    TCPSockIO.hs : Synchronous socket library, implemented using the
                   user-level, customized TCP stack.
    Mutex.hs     : A simple mutex library.


WebClient/  : An HTTP load generator application

WebServer/  : A web server application.  It can be linked with 
              either SockIO or TCPSockIO.

Compile and run:
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First, make sure that libaio is installed on your system and you are
using a development snapshot GHC 6.5.  Then, run the shell script
"rebuild.sh" to compile all the sources.  This should create three
executable files:

	WebServer/Server.bin
	WebServer/Server_tcp.bin
	WebClient/LoadGen.bin

Run them.  They are self-documented.  To use Server_tcp.bin, you should
first run "make setup" in the WebServer/ directory to setup iptables.
Read the Makefile for more information.

Programming with threads
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Just use Server.hs and LoadGen.hs as templates to start.

Programming with events
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The scheduler is part of your application.  You can use some standard
event loops predefined in Workers.hs, or you can write your own.


FAQ:
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Q: How to use another event source like *poll/*IO/kqueue/whatever?

A: First, wrap up the C function calls using FFI.  AIO.hs and
mod_aio.c is a good demo to start with.  Then, add system calls and
write your own event loops :-)

Q: How to add system calls?

A: The current setup is not quite modular yet---you will have to add a
line in Thread.hs for each system call you would like to add.  In the
future, it is possible to make the Trace interface user-pluggable by
adding an extra level of indirection.

Q: How to write my own event loops?

A: As a demo, LoadGen.hs has a customized event loop.  It does not do
anything fancy, though.

Q: How is the TCP stack?

A: The current implementation is purely functional and it is quite
   slow.  It is roughly 3x-8x slower than the linux kernel TCP stack.
   It only implemented server sockets---active TCP connections are
   not implemented yet.