Programming Languages on OpenVMS

Looking at OpenVMS administration, and investigating the possible languages to use on OpenVMS, there are many options – some supported by HP and some community open source options.

One of the first options is Perl; apparently Perl was originally designed as a way to write scripts that worked under UNIX and VMS both. Bernd Ulmann wrote an article for OpenVMS Technical Journal 13 about Perl on OpenVMS and gave a presentation on it in the spring of 2009 at an HP Connect OpenVMS Meeting (English translation) in Germany.

The HP version of Perl appears to be tied to the Secure Web Server (SWS) but it can stand alone.

Another language that is growing on OpenVMS is Java. Jean-Yves Bourles and Thierry Uso wrote on Java and OpenVMS in OpenVMS Technical Journal 10. Netbeans is available from HP to facilitate Java development on OpenVMS.

With Java available, that opens up the possibility of perhaps using a language that runs on the Java JVM as well. That brings to mind JRuby, Jython, Groovy, Scala, and Clojure. Information on most of these is rather scarce unfortunately; only Scala and JRuby have ports (both by the aforementioned Thierry Uso). Personally, these two are the most interesting to me; Scala has unmatched integration with Java itself as well.

Python is also available. Python seems to be the new administration tool of choice; at least, Red Hat seems to think that way.

As part of the Secure Web Server (SWS), you also get HP’s version of PHP. However, this does not seem to be a separate product as Perl is, and there is no description of using PHP as a scripting language (which you can do by running PHP against a file from the command line).

Lua is graciously made available for OpenVMS by our friends over at Hoffman Labs. Lua is a fantastic scripting language that doesn’t get the cover that it deserves.

Lastly, Tcl/Tk is available as well.

So which do I recommend? Well, Perl, PHP, and Java are all HP supported products, so one could start there. With Java, I see Scala and JRuby being fantastic languages as well, although they are not supported by HP. Lua is also a favorite of mine; an OpenVMS version is wonderful; however, Lua is not as widely available for other platforms as is Perl and Java.

I should mention that PL/I is still active on OpenVMS; it is commercially sold and supported by Kednos. PL/I was an interesting language, but it doesn’t have modern capabilities.

At the German openvms.org site there is also a big list of OpenVMS ports (including languages).

Are you ready for programming on OpenVMS? I am!

Writing Portable Administration Scripts

Writing portable scripts for UNIX and Linux is fairly easy – Korn shell is everywhere, and ksh scripts work the same and have the same basic tools available (sed, awk, pipes, etc.).

What about writing portable scripts to work on UNIX, Linux, and OpenVMS? UNIX and Linux are similar enough that things will work across the different platforms – the same holds for the BSD platforms and for Windows with the Cygwin utilities.  But radically different platforms such as OpenVMS require a different approach.

The first thing I did in looking at OpenVMS was to search out the languages and utilities that were available.  HP offers a number of open source tools, and has Freeware CDROMs available as well. SAIC has a large OpenVMS archive, including the contents of the HP Freeware CDROMs.

Under OpenVMS, I found these languages available:

• Java (built-in)
• GNU awk
• Perl
• Perl/tk
• tcl/tk
• Python

I doubt that Java would be used for scripting purposes, but it is becoming ubiquitous and if it is well-known by the scripter, it is possible that it could be used.

However, the other (add-on) alternatives seem to be much more likely.  Perl, Python, GNU awk, and tcl have extensive capabilities, and with tk visual displays are possible.  My main choice would probably be Perl.

The next step is to make sure that any coding that is done is truly portable.  Perl, with its extensive documentation, includes documentation specifically for portability and for OpenVMS as well.

The Perl portability documentation goes into complete detail about the various points that may trip a programmer up; in short, several of the main points cover:

• Data representation (high-endian order? low-endian order? line terminator?)
• File path representation
• Character sets and encoding (including order)
• Time and date representation

The best thing to do is to following the guidelines in the Perl portability document (even if using other languages) and to then test the portable code on all systems affected. Only in extreme circumstances should code be written specifically to the target system and selected based on target OS type.  Better to make it portable at its core.