Plan 9: why no compelling successor to Unix has got off the ground
It's a chapter from Eric Raymond's The Art of Unix Programming. His take is that Plan 9 wasnt enough of an advance over Unix to make a compelling switch. I think that, except for times when the market is in a state of flux, a new entrant with a modest improvement doesn't stand a chance. I remember reading a while back that a newcomer won't blow away an entrenched incumbent unless there is a 5 to one price performance advantage. This was the world of atoms, but something like that probably holds in software. Linux won because free trumps $500 per cpu, and it was really the same thing as Unix.
I used Plan9 for a while, I had a project going with some other people that involved a lot of distributed access, and Plan9 was pitched as solving a lot of our problems from the start, that we would have to hack around if we used anything else. (I describe the project down below, for the curious.)
The title, "Plan9: why no compelling successor to Unix has gotten of the ground" presumes that Plan9 is better than Unix. Plan9 sucks, and is a waste of your time.
The thesis of this article is that Plan9 was better than Linux, but Linux was good enough no one had a big enough reason to switch to go to the trouble; this fails to take into account that Plan9 was dead before Linux ever got out the door.
One reason for that was the license. For a while it was under some Bell Labs license that no one was sure was "open source" or not. As the Lucent took over the labs, and then had troubles itself, there was a lot of uncertainty about it. At some point the license was changed or clarified or something, and the new license could possibly be interpreted as allowing you to re-license it under the GPL, and there were rumours and hints that Rob Pike or some other iconic figure had told someone the goal of the license was to allow that, but it was obfuscated to get it past corporate lawyers. That didn't inspire confidence.
At one point in my life, I am embarassed to say, my goal was to spend the next year sitting down and reading every single source file in Plan9, putting a GPL or LGPL license on it, and then re-distribute "Plan9-GPL". I was convinced the license allowed it, and I figured that if I did it and was the obvious target for a law suit from Lucent and I was not sued, then Plan9 would take off. One good thing about Plan9 is that the total number of lines of code is low, one person could do that. However, like other powerful computer systems, sometimes there is a lot packed in few lines.
The user interface is worse than TWM. It's main editor basically requires that you constantly have one hand on the mouse and hunt and peck keys with the other hand, as if it was designed by one of those old computer illiterate people who can't type and clutch the mouse in a death grip the entire time they are in front of the computer. Certain people in the Plan9 "community" talk about rio like it is something better than Windows 2.0 or Commodore 64 GEM, and make a lot of jwz-like snarky comments about X, but it isn't.
I suspect the reason for this is that no one actually uses Plan9 on a daily basis. The headers of emails on the 9fans mailing list indicate that everyone except for a few holdouts uses Outlook. I think they edit their files in windows, and copy them to Plan9 via ftp or samba.
I wanted to document how to set up a "node" for our project in painstaking detail. As a result, I repeatedly wipped a disk using dd if=/dev/zero from tom's root boot floppy, and re-installed again. A few weeks into my experimenting, they updated Plan9 and it lost the ability to write the MBR, so I had to fdisk from a linux each time. This remained a bug for nearly two years, causing me to realize that in all probability, no one in the Plan9 developer community was installing any new computers.
That was a shock to me, as I had invested a lot of money in hardware that would run Plan9 (specific video cards and wireless cards, mostly) and a HUGE amount of time. When I saw some poor dude post on the 9fans mailing list 18 months later or whatever wondering why Plan 9 wouldn't boot after a clean disk install, I knew it was dead and that all that time was wasted.
I believe that most instances of Plan9 are currently run in VMWare on Windows desktops. If you are doing operating system research, and operating systems are the interface between application code and hardware, and you need a two layers of closed source between you and the hardware just to get started, you have failed.
It may have once been a framework for some cutting edge experiments in operating systems, and maybe still is. The C compiler it has is fast and nice, at least compared to gcc of the 2002 era or so. If I had some reason to write a C compiler, I would dig up the 9c code and take a look at it, and possibly start there.
I liked a lot of Plan9's ideas, but the whole experience made me appreciate linux a lot more. I don't think that Linux needs to take the best ideas from Plan9, Plan9 needs to steal the mediocre ideas from Linux -- like command completion, how about porting emacs or vi or nano, the basic stuff that allows you to get to working on the cool stuff.
The people involved with Plan9 seem very interested in the interface between application code and the operating system, and less interested in the operating system -- that's why they run Plan9 in Xen on a Linux computer. However, for people interested in that, they don't seem write much code that uses that interaction.
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P.S.: The project was to make this giant tit-for-tat resources trading system - we were starting with wireless access, so that if a person put up a wireless access point, you could use it only if you had a wireless access point at your house that was also open to the first person to use; next we were going to do offsite storage, so you would make a few gigs available to the system, and get a quota of a few back, but your stuff would be distributed and replicated accross many other people's drives thus resistent to disasters; and then a cpu trading thing similar to folding@home type systems; and so on. There was no business plan, our goal was to change the world not get rich (the participants came out of Austin's Cypherpunks group). We had a lot of excitement and hype going on, and it died due to interpersonal fighting (if you know the Cypherpunks from that time period you know what I'm talking about).
I'd forgotten that text doesn't show up with a link submission. Here's what I posted originally: Not new, obviously, but an interesting story for those of us who don't know it, and some generally applicable lessons. "In 2003 it looks like Plan 9 failed simply because it fell short of being a compelling enough improvement on Unix to displace its ancestor. Compared to Plan 9, Unix creaks and clanks and has obvious rust spots, but it gets the job done well enough to hold its position. There is a lesson here for ambitious system architects: the most dangerous enemy of a better solution is an existing codebase that is just good enough."
My long-held theory is it failed for lack of a blurb. When you visited the site, it was hard to figure out what Plan 9 was exactly. Digging into the documentation produced a link to a gzipped .ps file, and after installing Ghostscript, then Ghostview, then some fonts, then uncompressing the file and viewing it, one could read an academic paper describing in arcane language some problems of interest to file systems theoreticians. This state of affairs continued for years. Not surprising at all that it failed to get much traction.
A simple question: Rather than waiting for Linux to slowly absorb Plan 9's ideas, would there be some way to take all of Linux's drivers, scheduling, and other such excellent-but-non-OS-specific code, and code a new Plan 9 on top of that?
For anyone who wants to play with it, there appears to be a live CD:
FTP mounting as a filesystem was the big thing? Wowzers.