REXX

REXX is a programming language originally developed as a scripting language for IBM's VM/CMS operating system on mainframes.

In the intervening years (since early 1979) it has been deployed to nearly every operating system used on IBM computers, across the full range from mainframes down to desktop machines, under MVS, OS/400, AIX, OS/2, Linux, PC-DOS, and even Windows®.

It comes “free” from IBM for most of these, although they do make a charge for the Windows9x/NT version.

In addition, there are a number of freeware/shareware implementations for both these and other operating systems (including OpenVMS and the Amiga); about the only major omission is MacOS, sadly.

Object REXX (ORexx)

An extended version of Rexx exists for most platforms, and supports directly the precepts of object-oriented programming. Often a program written in ORexx will outperform an equivalent program written in “Classic Rexx”. Under OS/2 at least, it is easy to switch over to the use of ORexx, and most Classic Rexx programs will run unchanged.

If you're interested in getting yourself a copy of IBM's Object Rexx (for various platforms) then visit IBM Boulder

Use of Rexx by Dragonhill Systems

Due to its ease of use, especially for rapid prototyping, we at Dragonhill Systems often write programs in Rexx; the ready availability of support for TCP/IP Sockets programming has recently led us to write a number of Internet client and server programs in ORexx.

Most of these are still only fit for “in house” use, although some components are not too embarrassing to release in public, and at least one server daemon is now ready for beta testing

These are the programs currently under development:

• News Server (NNTPD) with related Unbatch and Expire programs
• Mail Server (SMTPD) for receiving incoming mail from the Internet and distributing to local mail boxes, and also for receiving outgoing mail from machines on a LAN and queuing it for later upload to the Internet
• Mail Client (SMTP) for uploading outgoing mail, either to an ISP's smart-host or direct to the designated MX relay hosts of the recipients
• POP3 Server Daemon (POP3D). This makes local mailboxes accessible to machines on the LAN, so that client software can access the mail that has been received by SMTPD. This is the only program that is (as yet) in a state suitable for beta testing: Download V0.25 (468kB). Please feel free to mail me with your critique of this program

In addition, a number of classes have been developed and used in one or more of these projects. One that I'm prepared to put on public display provides methods for a program to log messages through a syslog daemon; note that this does not implement the daemon itself (I use a public-domain implementation here under OS/2). This class is in the Syslog class. Once again, please feel free to send me your comments.

Links to REXX Information

The official home to Object Rexx is at IBM Hursley