What's GNU

This month's column concludes the article on Plan 9 From Bell Labs, and those parts of it that have been re-implemented in freely available software.
Experiences

I have been using this environment for almost two years, and find it to be clean, elegant, and easy to use. Initially, I started by using rc, and then sam when it became available in early 1993. Shortly after that, I started beta-testing 9term, in particular getting it to work correctly under SunOS. In the fall of 1993, the GWM Blit code became available, and I switched to that, using it for almost a year. In the spring of 1994, I started beta-testing 9wm, which was finally released at the end of 1994. I switched to es in January of 1993 after reading about it and hearing the presentation at the winter Usenix.

The research group at Bell Labs is well known for applying the “small is beautiful” principle to software design. This was initially true of Unix, and has been re-applied to distributed systems, shells, and user interfaces with Plan 9.

The interface is simple, consistent, easy to use, and very clean. All the programs described in this column behave the same way, in terms of what the buttons do, which window is current, and how the menus remember the previous operation.

An important point that I have not emphasized so far, is that all the programs use pop-up menus. I find this to be an enormous convenience, particularly compared to systems like Windows or the Macintosh, where you must move the mouse to the menu bar to pull down a particular menu. Pop-up menus save an incredible amount of otherwise useless mouse motion, leading to a system that is much easier to use.

My first exposure to window systems was long ago, on a Blit terminal. The interface was simple, clean and elegant. Ever since then, I had been searching for an X windows environment that matched the Blit's elegance. Now, with the combination of sam, 9term, 9wm and rc or es, I feel that I have finally found that environment, and I'm very happy. What's even nicer is that all of these programs are fast, and I have the broad range of X applications available to me also (xoj, anyone?). This latter point is unfortunately not true of the only other alternative, mgr (which I used until 9term became available.

Using These Programs Under Linux

All the programs described here can be made to compile under Linux. I don't have a Linux system of my own (believe or not!), but for a while I borrowed one, and was able to bring up all of these programs. Unfortunately, the system was a laptop, with too small a screen to make using X worthwhile. sam comes up fine, using the Make.solaris makefile as a starting point. 9wm also compiled just fine. 9term took a little bit of work, but it did compile and run. After asking on the mailing lists, I learned that 9term does not (yet) work quite correctly under Linux. This may be fixed by the time you read this column, though. Two people to contact for information about porting 9term to Linux are Pete Fenelon (pete@minster.york.ac.uk), and Markus Friedl (msfriedl@faui01.informatik.uni-erlangen.de). rc and es, both compile and run under Linux, but with some work. For rc, you have to generate the sigmsgs.c file by hand, based on /usr/src/linux/include/sys/signal.h. There is one other bug, reported by Jeremy Fitzhardinge, which is that rc uses ints for the array of additional groups, while Linux uses gid_ts, which are shorts. es requires similar changes for the signal handling, but these are actually documented in the Makefile.

Summary

The combination of 9term and 9wm provides a very close emulation of the elegant Plan 9 user interface. sam is a powerful, easy to use editor. rc is a simple, clean shell, and es is a nifty shell with lots of promise. It is worth reading the papers describing each of these components. The complete combination proves once again that “small is beautiful.”

Acknowledgements

Thanks to Chris Siebenmann and Daniel Ehrlich, maintainers of the various mailing lists, for their help, as well as to the members of the lists who responded to my questions about Linux. Thanks to Bob Flandrena, Paul Haahr, and Miriam Robbins for their comments.

References
  • Rob Pike, Dave Presotto, Ken Thompson, and Howard Trickey, “Plan 9 from Bell Labs”, Proc. of the Summer 1990 UKUUG Conf., London, July, 1990, pp. 1-9.

  • Rob Pike, Dave Presotto, Ken Thompson, and Howard Trickey, “Plan 9, A Distributed System”, Proc. of the Spring 1991 EurOpen Conf., Troms, May, 1991, pp. 43-50.

  • Rob Pike, “The Text Editor sam”, Software—Practice and Experience, November 1987, Vol. 17, #11, pp. 133-153.

  • Rob Pike, “8½, the Plan 9 Window System”, Proc. of the Summer 1991 Usenix Conf., Nashville, June 1991, pp. 257-265.

  • Tom Duff, “Rc—A Shell for Plan 9 and UNIX Systems”, Proc. of the Summer 1990 UKUUG Conf., London, July, 1990, pp. 21-33.

These papers are all available in Postscript as part of the Plan 9 documentation.

  • Paul Haahr and Byron Rakitzis, “Es: A shell with higher-order functions”, Proceedings of the Winter 1993 Usenix Conf., January 1993, pp. 53-62.

This paper is available for ftp along with the es source code.

Arnold Robbins (arnold@gnu.ai.mit.edu) is a professional programmer and semi-professional author. He has been doing volunteer work for the GNU project since 1987 and working with Unix and Unix-like systems since 1981. Questions and/or comments about this column can be addressed to the author via postal mail c/o Linux Journal, or via e-mail.

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