Tcl Distributed Programming (Tcl-DP) (Version 4.0a2; March 3, 1997) Brian C. Smith, Mike Perham, Tibor Janosi Department of Computer Science Cornell University This directory contains a freely distributable extension to Tcl/Tk called Tcl Distributed Programming (Tcl-DP). Tcl-DP adds TCP, UDP, and IP-multicast connection management, remote procedure call (RPC), and distributed object protocols to Tcl/Tk. A C interface to the RPC primitives is also provided. Background ---------- Tcl stands for the Tool Command Language, a freely distributable, embeddable scripting language package. Tk is an freely distributable window interface toolkit and widget library implemented by a collection of new commands added to Tcl. Information about Tcl/Tk is available from http://www.sunlabs.com/research/tcl. Tcl-DP was originally developed for Tcl 6.5 and Tk 3.0. Tcl-DP 4.0a2 is compatible with Tcl 7.6 and Tk 4.2. This distribution contains a loadable module for Tcl 7.6. HTML pages that describe the commands, and several examples that illustrate how to use Tcl-DP to build simple distributed applications. This file, and Tcl-DP source code, is available from http://www.cs.cornell.edu/Info/Projects/zeno/Projects/Tcl-DP.html Both source and binary releases are available from this location. In the examples subdirectory, several sample applications are supplied that use Tcl-DP. As you can see from the examples, the distributed programming mechanisms of Tcl-DP are very simple. A dp_RPC command, for example, sends a Tcl command to a remote process, which evaluates the command in the destination Tcl interpreter and returns the result as the value of the dp_RPC command. New Features in 4.0 ------------------- Tcl-DP 4.0 represents the first major rewrite of the code base since its beginning. This version is distributed as a loadable module for Tcl 7.6 that adds RPC and several communication protocols (TCP, UDP, IP-multicast, email, and serial lines) to Tcl. Tcl-DP 4.0 uses the Tcl channel abstraction for all I/O. DP's RPC layer has been rewritten to work with any DP registered channel, allowing RPCs to be performed across a normal TCP network, over a serial link or even via e-mail! DP 4.0 also introduces plug-in filters that that allow a programmatic filter to be inserted into any network layer, allowing experimental or secure protocols to be built easily. Summary of new features: * RPC over ANY read/writable non-blocking channel. * Tcl_Channel drivers for TCP, UDP and IP Multicast protocols. * Tcl_Channel drivers for serial ports and e-mail (via sendmail). * Plugin Filter API that can attach to a Channel and manipulate the incoming/outgoing data (i.e. uuencode/uudecode for email, sequencing for UDP, etc.) * Designed from the ground up to be portable and easily extensible (simple to add your own Channels or filters). How to compile the Tcl-DP 4.0 source ------------------------------------ On SunOS 4.1, Solaris 2.5, Linux 2.0, HP/UX 9.0: 1) Download the Tcl 7.6 source and unarchive it into a directory 2) Download the Tcl-DP 4.0 source and unarchive it into the same directory At this point, Tcl7.6 and Tcl-DP 4.0 should be sibling directories. 3) Make Tcl 7.6. See the Tcl docs on how to do this. 4) Change directory to tcl-dp/unix and type './configure' 5) Type 'make' 6) Assuming all went well, you can test the binary by typing 'make tests' This step is optional. 7) Please see "How to Install the Tcl-DP 4.0 Binaries" below. Windows: NOTE: You must have Microsoft Visual C++! 1) Download the Tcl 7.6 source and unarchive it into a dir. 2) Download Tcl-DP 4.0 source and unarchive it into the same dir. At this point, Tcl7.6 and Tcl-DP 4.0 should be sibling directories. 3) Make Tcl 7.6. See the Tcl docs on how to do this. 4) Change directory to tcl-dp/win and type 'nmake'. 6) Assuming all went well, you cam test the binary by typing 'nmake tests'. This step is optional. 7) Please see "How to Install the Tcl-DP 4.0 Binaries" below. How to install the Tcl-DP 4.0 Binaries -------------------------------------- Tcl-DP uses a homegrown tool to install itself: SPAM. SPAM is a Tk application that can manage Tcl packages and automatically install or uninstall them. To install the Tcl-DP binaries, simply run spam.tcl in wish and select 'File | Install'. Select dp.spm and SPAM should install DP into your Tcl/Tk installation. NOTE: we assume that wish has been installed correctly on your system. To use Tcl-DP ------------- Using Tcl-DP requires nothing more than wish or tclsh. All DP scripts should have "package require dp" as their first line which will automatically load the DP module if it has not been loaded already. NOTE: Due to the tclsh architecture, one must be careful with RPCs. tclsh does not run an asynchronous event loop and so one must poll for RPCs using update or vwait. Wish does not have this problem and we recommended it for writing and testing DP scripts. Documentation ------------- Documentation for the new DP 4.0 API and library functions is available in the doc subdirectory in standard HTML format. You can use any WWW browser to read the files. Bug Reports ----------- Send mail to tcl-dp@cs.cornell.edu. Credits ------- Tcl-DP 4.0 exists due to the following people: Brian Smith, Mike Perham, Tibor Janosi, Ioi Lam We extend our thanks to everyone who helped to create, debug, and distribute this software. Although there are too many people to mention at this point, the following people deserve special attention: John Ousterhout, creator of Tcl/Tk; Pekka Nikander, creator of tcpConnect; Tim MacKenzie, creator of tclRawTCP; Larry Rowe, co-creator of the original Tcl-DP; Lou Salkind, ported Tcl-DP to Tcl 7.0/Tk 3.3 R Lindsay Todd, developed security mechanism Peter Liu, developed extended name server code Ulla Bartsich, integrated many changes into Tcl-DP 3.3 Mike Grafton, wrote extensive test suites for Tcl-DP 3.x Jon Knight, wrote IP-multicast extensions to Tcl-DP 3.x Gordon Chaffee, ported Tcl-DP 3 to Windows-NT