[9fans] What makes Plan 9 unique?

[9fans] What makes Plan 9 unique?

[Matt Senecal]

I've been looking into Plan 9 for a while and may be asked to give a
presentation on it for some people at work. This newsgroup has been a big
help in getting my Plan 9 system (built 100% from donated & scrounged junk
parts) up and running, so I thought I'd ask this question here:

What makes Plan 9 truly unique? What about it makes it better than Solaris,
or other UNIX systems?

Imagine you're going to be giving the presentation to a bunch of long-time
computer users whose main attitude going into the meeting is going to be:
"Nice lines, but so what? Why should I consider Plan 9?"

I understand that I'm going to be learning a lot of this on my own in the
coming weeks, but I wanted to make sure that there wasn't some cool feature
that I missed. There's only so much you can learn on a standalone system
(although I may be networking with an old donated '486 if I can find some
NICs).

Re: [9fans] What makes Plan 9 unique?

[Lucio De Re]

On Thu, Oct 25, 2001 at 09:00:24AM +0000, Matt Senecal wrote:
> 
> What makes Plan 9 truly unique? What about it makes it better than Solaris,
> or other UNIX systems?
> 
I've been toying with lib9p over the past week and a lot of what
seemed an extremely handy but very remote paradigm (from the
developer's perspective, as a user I accepted it as a given) suddenly
took on a very concrete mantle.

If that doesn't do it, I also tried remote debugging of a Limbo
program on Inferno with mixed results (not being much of a debugger
freak).  The equivalent operation with acid over a network ought to
impress developers.  Even if done in two distinct rio windows.

> Imagine you're going to be giving the presentation to a bunch of long-time
> computer users whose main attitude going into the meeting is going to be:
> "Nice lines, but so what? Why should I consider Plan 9?"
> 
I wouldn't try that approach.  Perhaps "what can I learn from Plan 9?"
I was thrilled when I read the very old papers, without a clue about
the system itself.

> I understand that I'm going to be learning a lot of this on my own in the
> coming weeks, but I wanted to make sure that there wasn't some cool feature
> that I missed. There's only so much you can learn on a standalone system
> (although I may be networking with an old donated '486 if I can find some
> NICs).

Most of my Plan 9 network is '486s with NE2000s.  Not great, but
workable.  And very stable.  I was getting fileserver freezes which
were resolved (I don't know why) when I took the SCSI disk out and
reconnected all its cabling.  In all other respects, it seems totally
maintenance free.  Note that this is a hybrid of Second and Third
edition Plan 9, not yet up to date as regards releases.

++L

Re: [9fans] What makes Plan 9 unique?

[Douglas A. Gwyn]

Lucio De Re wrote:
> > "Nice lines, but so what? Why should I consider Plan 9?"
> I wouldn't try that approach.  Perhaps "what can I learn from Plan 9?"

I agree.  The idea that everybody would be better served by a sudden
switch to Plan 9 is utterly wrong.  There are a lot of factors
involved in choosing a computing platform.

Re: [9fans] What makes Plan 9 unique?

[Matt Senecal]

> I agree.  The idea that everybody would be better served by a sudden
> switch to Plan 9 is utterly wrong.

I understand that. The people I work for often don't. They live in a world
of budgets and let's-stick-to-what-worked-in-the-past. The attitude I
originally expressed was the correct one: that's the way *they* are going to
be thinking. It doesn't matter what I think -- I've got to pitch it to them
from their perspective.

Re: [9fans] What makes Plan 9 unique?

[Borja Marcos]

On Thursday 25 October 2001 11:00, you wrote:
> What makes Plan 9 truly unique? What about it makes it better than
> Solaris, or other UNIX systems?

	I don't think Plan 9 can or should be compared to Unix systems. Plan 9 is 
a distributed system, and Unix is not.

	One of the things that impressed me the most the first time I read a 
description (some years ago, long before AT&T decided to sell research 
licenses), was its capability to work in *heterogeneous* networks. It is
perhaps the most significant feature in Plan 9.

	Another distributed operating system, Amoeba, converts a whole network 
into a sort of huge multiprocessor computer (from the user's point of 
view), but it does not take into account the differences between networks, 
so Amoeba may be good for organizations with a high speed local network.

	Plan 9 does not have automatic process migration like Amoeba, but, for 
the designer of a distributed application, Plan 9 offers the ability to 
decide how to use the network depending on the available resources. The 
figure 1 in the original Plan 9 paper shows an example; CPU and file 
servers linked by a high-speed optic network, and remote terminals working 
from a phone line. The speeds can range from a 9600 bps line to a gigabit 
network.

	Plan 9 offers a per-process namespace that can be configured to make the 
network topology completely invisible to the user or the application 
program. Moreover, it has taken the "everything is a file" idea to the 
extreme. The network services, for example, are seen as files. To open a 
connection you only copy one "master" file, and the new file obtained will 
be the new connection.

	Together with this, Plan 9 offers a very clean network filesystem. It can 
export *anything*. One of my favourite examples is a machine "mounting" 
the TCP/IP stack of another through a network, or a process in one machine 
being debugged by a debugger in another. Classic network filesystems don't 
allow this flexibility.

	The window system makes a heavy use of the "everything is a file" notion, 
and it is extremely flexible and simple. It does not have a specialized 
protocol for network operations such as X11. Offering a file interface, it 
uses 9P. In fact, as the screen itself is a file, you can run one window 
system inside a window.

	This is what I liked most about Plan 9. There are obviously more things. 
The user interface is not the typical interface you see in the rest of 
environments, it shows new ideas. 

	I even love the documentation; a set of two books in the old Unix 
fashion. A set of very well written papers describing the different 
components and tools, and the manpages.

	Summarizing, in a time when you don't see anything new from commercial 
operating system vendors, and when everything is either Unix (note that I 
am a heavy FreeBSD user) or (argghhh) Windows, an operating system with a 
truly innovative design is fresh air ;-)




	Borja.

Re: [9fans] What makes Plan 9 unique?

[Russ Cox]

> [Being forced into a limousine.]
> The Dude: Hey, careful, man, there's a beverage here!

This is not 'Nam.  This is bowling.  There are rules.

I could easily see you as Walter.

Re: [9fans] What makes Plan 9 unique?

[Boyd Roberts]

> Dude, wake up!

[Being forced into a limousine.]
The Dude: Hey, careful, man, there's a beverage here!

Re: [9fans] What makes Plan 9 unique?

[David Gordon Hogan]

> [...]
> these are flaws in Windows.  A web page edit box that doesn't do the
> right thing, that's a flaw in the editor in question.

I believe that the editor in question is called
"C:\WINDOWS\SYSTEM\USER.EXE".

Though it might actually be in some other shared library.

I'm editting this message in rio, in case you wanted to
know.  Ya won't find that out by looking in some UserAgent
header...

Re: [9fans] What makes Plan 9 unique?

[William Josephson]

On Tue, Nov 06, 2001 at 05:53:20PM +0000, Thomas Bushnell, BSG wrote:
> rsc@plan9.bell-labs.com (Russ Cox) writes:
> > Dude, wake up!  He wasn't editing a web page.  He was
> > entering data into a form on a web page.  If you have your
> > web browser configured to let you use emacs to enter your
> > google searches, that's really impressive.
>
> If your web browser is emacs, it's not so impressive. ;)

No, that is even more impressive. :-/

  -WJ

Re: [9fans] What makes Plan 9 unique?

[Thomas Bushnell, BSG]

rsc@plan9.bell-labs.com (Russ Cox) writes:

> Dude, wake up!  He wasn't editing a web page.  He was
> entering data into a form on a web page.  If you have your
> web browser configured to let you use emacs to enter your
> google searches, that's really impressive.

If you web browser is emacs, it's not so impressive. ;)

Re: [9fans] What makes Plan 9 unique?

[anothy]

// And Microsoft Internet Explorer is very much a part of
// Windows proper, especially in the newer versions.

indeed, isn't that what much of the current fuss is about?
ア

Re: [9fans] What makes Plan 9 unique?

[Russ Cox]

> laid at its feet.  There are perfectly good editors available for
> Windows; you don't have to use the ones that come with.  A flaw in a
> "web page edit box" in Windows does not constitute a flaw in Windows.

Dude, wake up!  He wasn't editing a web page.  He was
entering data into a form on a web page.  If you have your
web browser configured to let you use emacs to enter your
google searches, that's really impressive.

And Microsoft Internet Explorer is very much a part of
Windows proper, especially in the newer versions.

> Jonadab, avid multibooter looking for a new OS to try out.

Well then try it out.

Russ

Re: [9fans] What makes Plan 9 unique?

[geoff]

emacs doesn't just replace half a dozen applications, it potentially
replaces all of them; you're limited only by the amount of emacs lisp
you can write before you get carpal tunnel syndrome.  i was somewhat
surprised that the gnu people actually bothered implementing a new
OS (the hurd); i assumed they'd just port emacs to the bare hardware,
or perhaps mach, to minimise porting effort.

i suppose if i said that sam or acme does all editing better than emacs,
emacs fans wouldn't take me seriously.  it's still true, though.
you can even read mail or netnews with acme, and with no lisp involved.

Re: [9fans] What makes Plan 9 unique?

[Jonadab the Unsightly One]

dhog@plan9.bell-labs.com (David Gordon Hogan) writes:

> The ``editor'' I was using was the Internet Explorer edit box widget.

As a Windows use, I just have to say that I can't fathom the
motivation for using MSIE as an HTML editor.  Might about as well use
MS Word for email.

Re: [9fans] What makes Plan 9 unique?

[Jonadab the Unsightly One]

Someone writes:
> Jonadab the Unsightly One <jonadab@bright.net> writes:
> > dhog@plan9.bell-labs.com (David Gordon Hogan) writes:
> > > Like when I go to edit a mistyped word in a web page edit box,
> > > and as soon as I've moused over the first character, the
> > > selection expands to the entire word.  The neighbours must
> > > wonder why I'm swearing so much.
> >
> > Clearly you are using an inferior editor.  Do not lay this at the
> > feet of the operating system.  You could download and install a
> > perfectly good editor, and then you would not have this problem.
> >
> > Windows has its _own_ problems.  It does not need to have the
> > flaws of other software attributed to it as well.
>
> Woah!  High flame alert on all counts; asbestos underwear: engaged.

No, it's true:  Windows has some inherent problems.  I say this as a
Windows user.  It does not need the flaws of inferior text editors
laid at its feet.  There are perfectly good editors available for
Windows; you don't have to use the ones that come with.  A flaw in a
"web page edit box" in Windows does not constitute a flaw in Windows.

Problems with the "Neighborhood" implementation of smb, bizarre
behavior when there are non-FAT logical partitons, a dynamic library
implementation that breeds version conflicts, lack of any protection
against wild pointers in one process scribbling over another process,
these are flaws in Windows.  A web page edit box that doesn't do the
right thing, that's a flaw in the editor in question.

> Really, you're not going to make friends posting
> pro-emacs stuff to 9fans.

Really?  What editor do y'all use?  What are its strengths?  What does
it do better than, for example, Emacs?  (Apart from taking less disk
space and less RAM, of course.)  I always like to check out
alternatives...

But the OP was talking about a Windows system, so an editor specific
to plan9 wouldn't be an option in that case, unless there's a Windows
port.  But there are lots of different editors freely available, so
there's no sense using one you don't like.  I don't.  I deleted
Notepad from my Windows system years ago, because I need an editor
with the power to do pretty much anything.  (Yes, I know it's bloated.
But since it substitutes adequately for at least half a dozen
applications, that's somewhat justified.)

--
Jonadab, avid multibooter looking for a new OS to try out.

Re: [9fans] What makes Plan 9 unique?

[David Gordon Hogan]

> > Like when I go to edit a mistyped word in a web page edit box, and
> > as soon as I've moused over the first character, the selection
> > expands to the entire word.  The neighbours must wonder why I'm
> > swearing so much.
>
> Clearly you are using an inferior editor.  Do not lay this at the feet
> of the operating system.  You could download and install a perfectly
> good editor[1], and then you would not have this problem.

The ``editor'' I was using was the Internet Explorer edit box widget.

> Windows has its _own_ problems.  It does not need to have the flaws of
> other software attributed to it as well.

That ``other software'' in this case _is_ Windows.

> [1]  Hint:  see UserAgent header.

``Clearly you are using an inferior editor''.

Re: [9fans] What makes Plan 9 unique?

[Jonadab the Unsightly One]

dhog@plan9.bell-labs.com (David Gordon Hogan) writes:

> Windoze _annoys_ me constantly (that is when I'm foolish
> or masochistic enough to bother using it).
>
> Like when I go to edit a mistyped word in a web page edit box, and
> as soon as I've moused over the first character, the selection
> expands to the entire word.  The neighbours must wonder why I'm
> swearing so much.

Clearly you are using an inferior editor.  Do not lay this at the feet
of the operating system.  You could download and install a perfectly
good editor[1], and then you would not have this problem.

Windows has its _own_ problems.  It does not need to have the flaws of
other software attributed to it as well.

-- jonadab

[1]  Hint:  see UserAgent header.

Re: [9fans] What makes Plan 9 unique?

[Dan Cross]

In article <vi4elnnpm9u.fsf@blue.cs.yorku.ca> you write:
>[i worry that if not the actors, certainly the overall direction is
>beginning to look more like that of the memorable movie it was
>named after... :-]

Really?  I didn't know that Bell Labs invented the Solamite, too....

	- Dan C.

(ps- having seen the movie, I have to disagree with your assertion.
Well, maybe I could see Boyd or Rob stomping about yelling, ``you're
stupid!  stupid!  stupid!  stupid!!''  [note that there might very
well be a ``, cross!'' after that.  Hi guys.])

Re: [9fans] What makes Plan 9 unique?

[David Gordon Hogan]

> whereas Windows
> still surprises me once in a while (though, to its credit, not as much
> as older versions did).

Windoze _annoys_ me constantly (that is when I'm foolish
or masochistic enough to bother using it).

Like when I go to edit a mistyped word in a web page edit box,
and as soon as I've moused over the first character, the selection
expands to the entire word.  The neighbours must wonder why
I'm swearing so much.

Windows: Throw it in the trash, it's worthless.

XP: (Chi-Rho): Heaven help us!

Re: [9fans] What makes Plan 9 unique?

[Skip Tavakkolian]

I suspect that a lot of poeple are incubating ideas. Many of the nuances
are missed unless you start writing and experimenting with your own
filesystem, or services, etc.  The ease of developing distributed
(geographically and functionally) systems is the Plan9 revelation.  I sense
that the critical mass is forming.  Also there is collateral effect that
Plan9 is having on other OSes.

The problem for a lot of us is that we have very little time to dedicate to
our causes; Plan9 is one of them. I suspect that most of us work on Plan9
on our own time and equipment. Given precious little time, should the
priority be on developing Plan9-workalike tools for environments that would
never support them the way Plan9 can, or should we develop tools like those
being suggested?

[How the movie ends is entirely up to us.]

At 10:16 AM 10/29/2001 GMT, Ozan Yigit wrote:
>presotto@closedmind.org writes:
>
>
>> Perhaps because noone in the community that writes code has it as
>> a very high priority?
>
>this is not the first time people made attributions to the community
>priorities, and i always wonder what those may be. here is an interesting
>platform that should be used for some important computational needs, but
>does it? i know a lot of people care, but what is being done with it?
>
>[i worry that if not the actors, certainly the overall direction is
>beginning to look more like that of the memorable movie it was
>named after... :-]
>
>oz 
>---
>www.cs.yorku.ca/~oz	 | if you couldn't find any weirdness, maybe
>york u. computer science | we'll just have to make some!   -- hobbes
>
>

Re: [9fans] What makes Plan 9 unique?

[David Gordon Hogan]

> Also there is collateral effect that
> Plan9 is having on other OSes.

Yep, it's a lot like what Jello Biafra referred to
as ``The Green Wedge'':

Microsoft ~ Republicans
Linux ~ Democrats
Plan 9 ~ Green Party

;-)

Re: [9fans] What makes Plan 9 unique?

[presotto]

[-- Attachment #1: Type: text/plain, Size: 147 bytes --]

So does this mean that you both care and are willing to write the code
or only that you think there is such a person?  If the former, thank you.

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From: Ozan Yigit <oz@blue.cs.yorku.ca>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] What makes Plan 9 unique?
Date: Mon, 29 Oct 2001 10:16:58 GMT
Message-ID: <vi4elnnpm9u.fsf@blue.cs.yorku.ca>

presotto@closedmind.org writes:


> Perhaps because noone in the community that writes code has it as
> a very high priority?

this is not the first time people made attributions to the community
priorities, and i always wonder what those may be. here is an interesting
platform that should be used for some important computational needs, but
does it? i know a lot of people care, but what is being done with it?

[i worry that if not the actors, certainly the overall direction is
beginning to look more like that of the memorable movie it was
named after... :-]

oz 
---
www.cs.yorku.ca/~oz	 | if you couldn't find any weirdness, maybe
york u. computer science | we'll just have to make some!   -- hobbes

Re: [9fans] What makes Plan 9 unique?

[bwc]

> i know a lot of people care, but what is being done with it?

Do you mean `done WITH it' or `done USING it'?  I've been developing
products USING plan9 since the second edition, and used the Unix
plan-9-like stuff before that.  We are not many but much greater than one.

  Brantley

Re: [9fans] What makes Plan 9 unique?

[Ozan Yigit]

presotto@closedmind.org writes:


> Perhaps because noone in the community that writes code has it as
> a very high priority?

this is not the first time people made attributions to the community
priorities, and i always wonder what those may be. here is an interesting
platform that should be used for some important computational needs, but
does it? i know a lot of people care, but what is being done with it?

[i worry that if not the actors, certainly the overall direction is
beginning to look more like that of the memorable movie it was
named after... :-]

oz 
---
www.cs.yorku.ca/~oz	 | if you couldn't find any weirdness, maybe
york u. computer science | we'll just have to make some!   -- hobbes

Re: [9fans] What makes Plan 9 unique?

[pac]

>> > There is a lot to be said for keeping system structures as modular
>> > as possible, to increase options for how things can be configured.
>> 
>> I think you just supported my point.
>> 
>> Russ
>> 
>> 

Nice to hear that!


--
Peter A Cejchan

Re: [9fans] What makes Plan 9 unique?

[okamoto]

>so Amoeba may be good for organizations with a high speed local network.

Amoeba looks terminal just as dumn terminal with graphics (==Xserver).
I felt this was a choice from the theoretical point of view, to make it clear
what is CPU POOLs in Amoeba.   However, yes, I prefer the 9 termianl style
more.  It also seems more fit to the recent powerful PCs.

Kenji

Re: [9fans] What makes Plan 9 unique?

[forsyth]

[-- Attachment #1: Type: text/plain, Size: 198 bytes --]

the implementation probably is fairly easy, and i suspect
that's all that russ referred to.  knowing what to implement
is another matter entirely, and that's probably why it hasn't
been done.


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To: 9fans@cse.psu.edu
Subject: Re: [9fans] What makes Plan 9 unique?
Date: Fri, 26 Oct 2001 16:48:50 GMT
Message-ID: <87adye1heb.fsf@becket.becket.net>

rsc@plan9.bell-labs.com (Russ Cox) writes:

> But since the interface is entirely separate, it would be easy to
> write interactive support for the terminal (a la screens), without
> shells and other programs needing to know.

"It would be easy to..." is always a weak argument.  Blind people are
here today, using GNU/Linux systems with alacrity.  Why is a suitable
Plan 9 interface not available, if it's so easy?  I suspect it would
actually take a bit of work.

Thomas

Re: [9fans] What makes Plan 9 unique?

[presotto]

[-- Attachment #1: Type: text/plain, Size: 90 bytes --]

Perhaps because noone in the community that writes code has it as
a very high priority?

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From: "Thomas Bushnell, BSG" <tb+usenet@becket.net>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] What makes Plan 9 unique?
Date: Fri, 26 Oct 2001 16:48:50 GMT
Message-ID: <87adye1heb.fsf@becket.becket.net>

rsc@plan9.bell-labs.com (Russ Cox) writes:

> But since the interface is entirely separate, it would be easy to
> write interactive support for the terminal (a la screens), without
> shells and other programs needing to know.

"It would be easy to..." is always a weak argument.  Blind people are
here today, using GNU/Linux systems with alacrity.  Why is a suitable
Plan 9 interface not available, if it's so easy?  I suspect it would
actually take a bit of work.

Thomas

Re: [9fans] What makes Plan 9 unique?

[Thomas Bushnell, BSG]

rsc@plan9.bell-labs.com (Russ Cox) writes:

> But since the interface is entirely separate, it would be easy to
> write interactive support for the terminal (a la screens), without
> shells and other programs needing to know.

"It would be easy to..." is always a weak argument.  Blind people are
here today, using GNU/Linux systems with alacrity.  Why is a suitable
Plan 9 interface not available, if it's so easy?  I suspect it would
actually take a bit of work.

Thomas

Re: [9fans] What makes Plan 9 unique?

[Russ Cox]

> > ... there is no tty driver in the kernel.  The window system
> > handles the nuances of terminal input.
> 
> Not for a terminal on a serial port, it doesn't.  Braille terminal
> users (for example) are ill-served by embedding interactive support
> in a windowing graphics interface.

But since the interface is entirely separate, it would be easy to
write interactive support for the terminal (a la screens), without
shells and other programs needing to know.

> There have been many "integrated" OSes; for example TI's 900-series
> (before the 990) came with an OS that integrated the terminal driver
> and consequently supported *only* specific TI video terminals with
> special high-speed cabling.  That design probably contributed to the
> lack of commercial success for those systems.

Buh?  As another example, all Unix clones come with an OS that
integrates the terminal driver.  So does Windows.  That design apparently
hasn't hurt the commercial success of those systems.

> There is a lot to be said for keeping system structures as modular
> as possible, to increase options for how things can be configured.

I think you just supported my point.

Russ

Re: [9fans] What makes Plan 9 unique?

[Douglas A. Gwyn]

Russ Cox wrote:
> ... there is no tty driver in the kernel.  The window system
> handles the nuances of terminal input.

Not for a terminal on a serial port, it doesn't.  Braille terminal
users (for example) are ill-served by embedding interactive support
in a windowing graphics interface.

There have been many "integrated" OSes; for example TI's 900-series
(before the 990) came with an OS that integrated the terminal driver
and consequently supported *only* specific TI video terminals with
special high-speed cabling.  That design probably contributed to the
lack of commercial success for those systems.

There is a lot to be said for keeping system structures as modular
as possible, to increase options for how things can be configured.

Re: [9fans] What makes Plan 9 unique?

[Russ Cox]

http://www.eecs.harvard.edu/~rsc/plan9.html

Why Plan 9?

Why Plan 9 indeed.  Isn't Plan 9 just another Unix clone?  Who cares?

First, Plan 9 presents a consistent and easy to use interface.  Once
you've settled in, there are very few surprises here, whereas Windows
still surprises me once in a while (though, to its credit, not as much
as older versions did).  After I switched to Linux from Windows 3.1, I
noticed all manner of inconsistent behavior in Windows 3.1 that Linux
did not have.  Switching to Plan 9 from Linux highlighted just as much
in Linux.

One reason Plan 9 can do this is that the Plan 9 group has had the
luxury of having an entire system, so problems can be fixed and
features added where they belong, rather than where they can be.  For
example, there is no tty driver in the kernel.  The window system
handles the nuances of terminal input.

If Plan 9 were just a really clean Unix clone, it might be worth
using, or it might not.  The neat things start happening with
user-level file servers and per-process namespace.  Recall that in
Unix, /dev/tty refers to the current window's output device, and means
different things to different processes.  This is a special hack
enabled by the kernel for a single file.  Plan 9 provides full-blown
per-process namespaces.  Thus, in Plan 9 /dev/cons also refers to the
current window's output device, and means different things to
different processes, but the window system (or telnet daemon, or ssh
daemon, or whoever) arranges this, and does the same for /dev/mouse,
/dev/text (the contents of the current window), etc.

Since pieces of file tree can be provided by user-level servers the
kernel need not know about things like DOS's FAT file system or
Linux's EXT2 file system or NFS, etc.  Instead, user-level servers
provide this functionality when desired.  In Plan 9, even FTP is
provided as a file server: you run ftpfs and the files on the server
appear in /n/ftp.

We need not stop at physical file systems, though.  Other file servers
synthesize files that represent other resources.  For example, upas/fs
presents your mail box as a file tree at /mail/fs/mbox.  This models
the recursive structure of MIME messages especially well.

As another example, cdfs presents an audio or data CD as a file
system, one file per track.  If it's a writable CD, copying new files
into the /mnt/cd/wa or /mnt/cd/wd directories creates new audio or
data tracks.  Want to fixate the CD as audio or data?  Remove one of
the directories.

Finally, Plan 9 fits well with a networked environment.  Since files
or directory trees can be imported from other machines, and all
resources are files or directory trees, it's easy to share resources.
Want to use a different machine's sound card?  Import its /dev/audio.
Want to debug processes that run on another machine?  Import its
/proc.  Want to use a network interface on another machine?  Import
its /net.  And so on.