Why Plan-9?

[Jim Choate]

On Sun, 21 Oct 2001, Karsten M. Self wrote:

> This says nothing about current development.  Word I've heard (from
> someone tangentially involved with the project) was that the release was
> something of a desperation move.  As someone who watches free software
> licences closely, the Plan 9 license is one of the more twisted bits of
> corporate-authored licenses.  Not necessarially bad, but it reeks of
> compromise clauses speaking to internal battles.  Rumor was that a
> codebase that had been stable for a couple of years saw a slew of
> commits in the weeks leading to the public release.

??? Plan 9 was released Open Source in 2000. Prior to that it had a weird
'no commercial use' clauses. It apparently was intended as a internal use
only project. Forces both internal and external began fighting for the
release of the Rev. 2 code (which turns out can't be done) so instead Pike
and the others created a Rev. 3. They are now working on what is called
the "2000 Release". Haven't had a chance to try it yet.

> How about its external use track record?

None, see commentary above. I've been an avid follower of Plan 9 since '86
when the first papers started to appear. It's current state with respect
to apps is about where Linux was in '92. With respect to the code, it
works and works well. The fathers of Unix did as good a job here as well.

> The license is *not* OSI certified, nor is it considered Free Software
> by the FSF.

<shrug> Ask me if I care.

Read Lessigs "Code".

> >  - Fully distributed in both process and file space
> 
> Meaning...?

Meaning that through your I/O server you see an effective pool of many
processors on which you can then use to execute your programs. It means
that the filesystem components that appear 'local' may actually not be. It
means that things like backups and such can be left to the filesystem to
take care of 'under the covers' so to speak.

> >  - Filesystem is fully transitive, everything is treated like a file.
> >    This creates some unique opportunities to make publicly shared but
> >    privately maintaned resource pools. Hangar 18 is an attempt to do
> >    just this.
> 
> What does this mean?  How does this compare with,

Transitive means that A mounts B, C mounts A and gets B free. Plan 9 does
this, managed by a set of authorization layers for fine control, native.
This means that when Hangar 18 goes online you can mount /hangar18 into
your filespace (via Plan 9 or Linux NFS services) and you will get all the
resources that Hangar 18 mounts through that point. ftp is a good example.
In Plan 9 you 'mount' the ftp server to your file system. If you ever go
out and walk that part of the file space tree and request a file it only
then goes and gets it. You can control its lifetime (to manage disk space
for example) via local cache controls. A 'lazy update' mechanism, very
efficient of network and local resources.

> say, GNU/Linux and /proc?

Irrelvant comparison.

> >  - The filesystem is structured and featured in such a way that RDBMS
> >    sorts of solutions are moot. These functions are built into the
> >    filesystem itself (though not through SQL compliance).
> 
> How does this compare with, say, journaled filesystems?  I'm not
> challenging, I don't understand the statement above and am not familiar
> with the technology.

You can build a journaled filesystem layer onto Plan 9 through scripts
that define how the various servers are supposed to journal the
individual compnents.

> 
> >  - Encryption (currently DES, needs fixing) built right in.
> 
> Built into what?

The network layer. The traffic between any two Plan 9 boxes is encrypted
with keys dependent upon the individual boxes (or larger classes if you
desire) if the system is so configured. You can also use this to encrypt
branches of your filesystem. Plan 9 provides SSH.

> >  - Doesn't use passwords, Instead it uses tickets (ie certificates).
> 
> ...which are granted via...?

However the resource owner choses. I'm using 'small worlds network' models
for my 'web of trust'...

> Passwords, perhaps?

But the passwords don't go across the network, therefore they're not
'used' in the conventional sense.

> >  - Has a wickedly new GUI.
> 
> Oh, now *that's* compelling....

It should be, X Windows sucks.

> >  - Supports Inferno (run-time included) so that you can access one of the
> >    leading 'Internet Appliance' work environments. Plan 9 isn't real-time,
> >    but Inferno is. (It makes my Lego Mindstorm look like a directory tree, 
> >    makes programming real-time hardware operations rather easy)
> 
> What's Inferno?

Another OS, intended for real-time control of "Internet Appliances". You
run it along side Plan 9.


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