Stem Version 0.11
=================
Fri Dec  1 03:50:58 EST 2006


* The Stem event loop is layered and can easily wrap other event
  loops. Supported event loops include Event.pm, perl/tk and wxperl and
  a pure Perl event Loop. See Stem::Event.pm and Stem::Event::EventPM.pm
  for more.  Other event loops that need wrapping include POE, Gtk and Qt.

* There is a pure Perl event Loop so Stem now runs on windows or on any
  system where Event.pm isn't installed. 

* Full support for SSL on all socket related objects and cells.
  Converting from a plain socket to an SSL socket just requires adding
  the SSL arguments to the Stem::Socket contruction. All Stem modules
  that use sockets use Stem::Socket which in turn uses IO::Socket::SSL
  (and that needs openssl). If that module is not installed, its test
  will be skipped.

* There is a Stem::UDPMsg cell that provides a UDP socket client and/or
  server.

* The new Stem::Cell::Flow module provides a way for Stem cells to
  handle a mix of sync/async (local/remote) method calls. You can create
  a logic flow with if/else/while command in a simple mini-language.
  This allows a cell to do complex operations such as accessing a DB
  (via Stem::DBI) or fetching web pages and mix that with local method
  calls that crunch the data. Normally this would entail a complex state
  machine or having each method know the next one to call but
  Stem::Cell::Flow allows you to convert that to a much simpler logic
  flow. See the test script t/cell/flow.t and the lib/Stem/Test/Flow.pm
  module for more on this. It requires Parse::RecDescent to be installed
  (the test will be skipped if it is not found).

* A bunch of new tests were added:

	Event loops
	Sockets (both with and without SSL)
	Stem::Cell::Flow

* There is a brand new install based on Module::Build. A Makefile.PL is
  provided but it is a wrapper around the Module::Build installer. Stem
  can now be installed with CPAN.pm

* There is more pod (and more is needed). All contructor attributes are
  now automatically updated to pod by the stem2pod utility. That script
  also inserts pod templates for all methods. This will make it easier
  to add pod and keep it up to date.

* Cleaned up the INSTALL, README and other top level documents.

* Many more changes than I have room to write in this file.

Stem Version 0.10
=================
Nov-11-2002

* The version number has been bumped to 0.10 because of the large number
  of changes and the major improvements in reliability and speed.

* Renamed Stem::TtyMsg to Stem::Console. Now it doesn't need any
  arguments to be initialized. A Stem envioronment variable can be set
  which will disable it. All the configuration files and demo scripts
  have been updated to use it. The old TtyMsg module has been deleted.

* Added Stem::Test::Echo.pm and Stem::Load::Driver.pm. They support
  benchmarking of basic message passing in multiple modes.

* Stem::Msg now only accepts the string format of message
  addresses. This speeds up message creation and simplifies message
  handling and delivery.

* Stem::Class now supports attribute type checking and
  conversion. Supported types include boolean, list, hash, LoL (and
  friends), object and handle.

* Stem::Conf has better error reporting. The Cell name and class are now
  printed with the error.

* Added the reply_type field to messages. This is used to make simple
  state machines with messages (used in the work sequencing system).

* Stem::Portal has been improved and now use the Stem::Packet module to
  handle its buffering.

* Added Stem::Packet and Stem::Codec::*. These modules support
  serializing (marshalling) Stem data for use in pipes and files. The
  codec to be used can be selected in the configuration file. This is
  now used in Stem::Portal and all worker mode operations. Current codec
  include Perl (Data::Dumper/eval), YAML, and Storable.

* Split Log.pm into Log.pm and Log/Entry.pm. Moved Stem::LogTail.pm to 
  Stem::Log::Tail.pm. Added Stem::Log::File which handles physical log
  files including rotation and archiving.

* Added Stem::Trace.pm which gives modules a simple way to inject log
  entries during program execution. It allows for creation of customized
  Trace functions which can have defaults and different calling styles.

* Split Stem::Cell.pm into multiple files to make it easier to
  maintain. These include Stem::Cell::Sequence.pm, Stem::Cell::Clone.pm,
  Stem::Cell::Pipe.pm and Stem::Cell::Work.pm 

* Added the Stem::DBI module which is a Stem message based front end to
  DBI. This Cell can be configured with the all the SQL needed for your
  application which is shared by all the Cells that use it. It can be
  run in its own Stem Hub (process) thereby providing non-blocking
  access to the DB from other Hubs. A farm of these proxies can be
  created and managed by a WorkQueue Cell which will support parallel DB
  access from one or more Hubs.

* Added work sequencing support in Stem::Cell. This allows any Cell to
  call local or remote methods and to manage their flow control. This is
  an interim version that will be superseded by a new mini-language that
  will be easier to code and will support more complex flow
  (e.g. if/else/while). This is a very powerful feature that simplifies
  complex state operations to simple flow control statements.

* Added the Stem::WorkQueue module which allows a set of work request
  messages to be distributed to a set of worker Cells. Modified
  Stem::Cell to support a cell to request a new work message.

* Created worker mode where an object (or data structure) gets
  sent to a Cell via a message. The Cell can then write the object to a
  socket or process or crunch it. The Cell then gets back the object
  (presumably modified) and sends it back to the originator of the work
  request. This is done in Stem::Cell and used in Stem::Proc,
  Stem::Sock::Msg and Stem::DBI. 

* Created worker ready mode where a Cell can send out a message stating
  it can receive a work message. Typically this will go to a WorkQueue
  Cell. This message is sent out when the Cell starts up or after it
  completes a previous work request.

* Added Stem::Boot.pm which will run a set of external programs and
  monitor them. Their output can be logged and they can be
  restarted. Other options (for each program) include setting the
  initial directory and which host to run it on (via ssh if desired).
  The set of programs and options are loaded via a configuration file
  specific to this module.

* Added Stem::Inject.pm which has one method which will connect to
  a Stem Hub and send it a single message. Then it will read back a
  single message and return its data. This is meant to be used in Perl
  programs that are not Stem driven and want to communicate with Stem
  cells.

* Updated the Stem Cell cookbook with more examples. It now shows how to
  create class and object cells and also how to create cloneable Cells.

Stem Version 0.06
=================
Feb-26-2002

* Stem is now released under the GPL. If you want to use Stem in a
  product that will be sold, contact us about acquiring a commercial
  license.
	
* A simple and easy to use installation script is now included.  The
  installation script allows you to have a Stem environment up and
  running in a matter of minutes. Read the INSTALL document to learn how
  to run this script.

* There is a new set of cookbook documents with examples.  These show
  you how to develop new Stem Cells.

* Complete documentation is now included for all demonstration
  scripts included with Stem.

* Stem Message Addresses can now be in a string form as well as the hash
  form. This simplifies creating addresses in Stem configurations. All
  the installed configurations now use this format. See the Address
  design notes for more on this.

* The Stem::Cell module has been added. It supports generic functionality for
  Stem Cells, including cloning, asynchronous I/O, and pipes. It
  currently is used by the Stem::Proc and Stem::SockMsg modules. All
  future Cells that need those services can use this module.

* The modules Stem::Proc and Stem::SockMsg have been rewritten to use
  Stem::Cell.  They are much shorter and simpler now that the common
  Cell functions are handled by Stem::Cell.

* A new module, Stem::Gather, has been added. It allows you to
  synchronize multiple asynchronous events. It triggers a callback when
  all of its required tokens have been 'gathered'.

* Bug fixes and general system improvements.
