Plan 9 from Bell Labs (1995)
plan9.bell-labs.com
plan9.bell-labs.com
I've done quite a bit of poking around in Plan 9, but of course I don't know all of it. I've hacked in the kernel and worked on the 64-bit version as well, I've fooled with the compilers, and I've hacked on the window manager.
If anyone wants to ask questions about some aspect of Plan 9, I'll do my best to answer--and if I can't, I bet others can jump in and take over. It would be great to clear up some of the misconceptions, myths, and FUD!
However, I would guess that had it been freely available when it was released in the early 90's then it actually would have more of a presence vis-a-vis Linux today.
1. As others pointed out, Plan 9 was not initially free. If you go back and look at the very oldest messages from the 9fans mailing list (http://9fans.net/archive/, starts in 1993) you'll see lots of messages from people just trying to figure out how to get a license. At the same time, you could get Linux for free or very cheap.
2. Plan 9 is unfamiliar for new users. Face it: most people define "intuitive", "powerful", and "useful" as "that thing I'm already used to". Programming in Plan 9 is pretty similar to programming Unix, and the shell feels much the same, but you still need to learn new concepts and people don't like that.
3. Plan 9 is not Unix. People have, from the beginning, wanted to reshape Plan 9 in the image of the Unix/Linux environments they are familiar with, even when it doesn't make sense. They want Emacs or Vim, without having even tried Acme or sam. They want bash, ssh, X11, Firefox, and GNOME. Some of this software, like ssh, X11, and even Vim, have been ported or re-implemented because they're useful for interoperability with Unix or simply because somebody wanted it bad enough to do the port (Vim).
Those aren't the only reasons, but they're pretty substantial.
As for what the next kernel/OS should do, I'd say it's not enough to just exist and be good. You have to be used widely and have enough developers become familiar with it. If, for instance, some engineer at Facebook comes up with a nifty kernel and convinces them to start using it on all their servers, that kernel will probably be successful outside because there's suddenly a massive deployment of it.
Alternately, if you can get into a market that's less entrenched than the desktop, you may have a chance. We saw this to some extent with netbooks (some of the earliest ones shipped with Linux by default), we've definitely seen it with smartphones, and I have a feeling that we may see it in tablets. The problem with the desktop frequently comes down to: "Why can't it run Firefox and open my Word documents?"
The command language is powerful enough to do what I want day-to-day. It's easy to apply an editor command across every open buffer, if you need to refactor for instance. Like emacs, you can write applications which run in Acme; we have a mail client, news reader, CD player, and IRC client (among others).
When it comes time to compile, I can execute a "mk" command from within Acme by simply typing "mk" anywhere and executing it with the middle mouse button--this isn't just for mk, you can do that with any command. It'll put the output in a new buffer, and if there are compilation errors, you just right-click on the filename:line-number (foo.c:42) and Acme instantly jumps you to that line of the file.
There are more cool things about Acme, but I can't sit here and type all day! It's basically what you get when you take the Unix concept "It's all just text" and make an editor out of it: text is content, text acts as commands, text is for searching.
As as example:
Edit X/.* / ,s,loginAdmin,loginIdiAmin,g
I edit this text (in a guide file for the current directory) to suit my current need; highlight it by dragging while the left mouse button is down; and then middle-click anywhere on the highlight to run it. After I run it, every open buffer that was changed gets a dirty-bit marker, and I can either middle-click the word Putall (usually in the top row) to save all the files' changes, or Undo (in any buffer's tag) to undo all of the changes across all buffers.
Edit is a separate executable which Acme runs. It talks behind the scenes to all the control files Acme publishes for the files it edits, just like any program you could write yourself. So the editing features are not built into the Acme executable, and are independently changeable. This outsourcing of even core (to other editors) functionality inverts the emacs approach, which brings everything into a big global elisp space.
X/.* / says to address every open buffer, since .* matches any pattern. There should not usually be a space after the asterisk, but HN's formatdoc makes the following text italic and removes the asterisk if I don't put a space there. (In Inferno Acme this particular case appears to work anyway, probably because of the space after the filename in buffer tags.)
,-before-s says to edit the entire content of the buffer, not just a highlighted section.
s,loginAdmin,loginIdiAmin, is a tasteless replacement command in Edit's dialect of sam (and in ed, sed, vi, and vim). These commas could be replaced by any character, as long as that character is not in the set of characters to be replaced, or in the replacement set.
g-after-, says to replace every instance of loginAdmin, not just the first.
* Do not be hostile to your potential users. (The community that formed around Plan 9 as it went open source were quite hostile, there's no need for public beatings just because someone suggests to port X11 to Plan 9 even if it's a bad idea).
I remember at FOSDEM a few years back, there was this Spanish dude and some of his friends, who were frothing-at-the-mouth fans of Plan 9, and, as they became progressively more inebriated in the place where a bunch of us were staying, he kept ranting louder and louder (and more by himself) about the perceived injustices and deficiencies of a world where Linux was more popular than something so beautiful, so elegant, as Plan 9.
It was ... a bit disturbing to watch. That kind of passion should be reserved for relationships with other people.
I think part of the problem with its diffusion was that it only became free software a decade after Linux, with no clear niche to attack (see: Crossing the Chasm) and make its own.
For what it's worth, I use wmii on Linux, which uses the Plan9 model for configuration. It makes it super-scriptable and really easy to use.
Plan 9 wasn't always free.
Also, its GUI sucks. That's sort of important for end users.
Another is that there are no "decent" editors. For many people, the definition of "decent" means the executable must be named "vim". As I've said elsewhere, Plan 9 actually has a port of Vim, but if you skip our excellent native editors to use Vim, it's like visiting a foreign country and eating only McDonalds because the local cuisine is unfamiliar.
In a related vein, I idly wonder if there's a project around intended to bring useful security to a practical Unix derivative. Nobody uses a big timesharing box any longer (for all reasonable definitions of nobody); and the protections mooted to keep "users" away from "wheel" are basically pointless and counterproductive in a world where attacks come from outside. Apple's code-signing is one reaction to this new reality; what's the current status of capability based systems?
Attacks may come from the outside, but they usually exploit code running on the target. IIRC, Apparmor is an implementation of what you seek - an easy way to limit what any given executable can do, in addition to what its process credentials can do.
I just think it is TRAGIC and a HUGE waste that such an elegant and beautifully-designed OS as Plan 9 continues to basically sit in a backwater, ignored and unused by almost everyone. And it is sitting there when I am convinced that a P.D. release would see its use rocket into the stratosphere.
What would be the harm in releasing it to the public domain? It is already open-source so it's not as if any revenue would be lost. It would be a good P.R. opportunity for Bell Labs too (and as I say, a nice way of honouring D.R.
Let's face it - if Unix itself had been released as P.D. in the first place, then there would have been no need to reinvent it (as with the BSDs and Linux). It could simply have been continually improved upon. That's where I'm "coming from", as it were.
SQLite shows what is possible with P.D. code. It is apparently used in darned-near every smartphone out there, so it's not as if companies won't use P.D. code if it is good enough. If it meets their needs, they will go for it.
Also Linux union mounts are clunky and not as useful as they are in Plan 9 because you can't have private namespaces if you are not root.
...which is why we're still using Unix.
It had a lot of promise. What did become of it I wonder?
Bell Labs still uses plan 9 internally and develops it.
9front is a community fork of Plan 9 with a bunch of interesting changes.
There's a small but interested community of die-hard plan 9'ers that care about it, and the principles it set forth. A lot of it came from some very good, very sane development with people who often spend more time thinking than coding (a virtue we could all benefit from I think)
Oh, and you can run Vim on Plan 9 now. But it's kind of like visiting a foreign country and eating only McDonalds.
But it is a really good editor, just not to my taste.
That was my major complaint about Plan 9 in general. As far as I could tell, it really wanted me to run with a one-handed keyboard and mouse.
...that plus the fact that Bell Labs invented "Not Invented Here" Syndrome.