Re: [9fans] got a new feature: learning of resources and switching among them

Re: [9fans] got a new feature: learning of resources and switching among them

[Keith Nash]

1.
Are redirfs, badsrv, intended to do the same thing as "Plan B"?

2.
> > Did anyone (anywhere) ever implement the Resource Location Protocol?
> >
> >    ftp://ftp.rfc-editor.org/in-notes/rfc887.txt
>
> I'm not certain, but it's functionally similar to a half-dozen other
> protocols, such as Service Location Protocol (
> http://www.faqs.org/rfcs/rfc2165.html ) which I think only Sun and Apple
> ever put into use, and then Apple abandoned for multicast DNS (
> http://www.multicastdns.org/ ) and DNS Service Discovery (
> http://www.dns-sd.org/ ).

Apple's latest use of this technology is Rendezvous, which is part of OSX, and is open-source:

Open source project page and download: http://developer.apple.com/darwin/projects/rendezvous/

OSX glossy page: http://www.apple.com/macosx/jaguar/rendezvous.html

press release: http://www.apple.com/pr/library/2002/sep/25rendezvous.html

3.
>
>       We are all interested in the future for that is where you and I
>       are going to spend the rest of our lives.
>
>                               Criswell, "Plan 9 from Outer Space"

The film that our favourite OS is named after is SO, SO, BAD, that if you start to watch it, the only ways to avoid being bored to death are: (a) to switch it off immediately; (b) to gnaw off your own left leg.  Anyone who remembers dialogue, or the names of characters, must obviously have chosen the latter route.

Re: [9fans] got a new feature: learning of resources and switching among them

[Russ Cox]

I sure wish other OSes would get around to implement this rendezvous:

http://plan9.bell-labs.com/magic/man2html/2/rendezvous

> The film that our favourite OS is named after is SO, SO, BAD, that if
> you start to watch it, the only ways to avoid being bored to death
> are: (a) to switch it off immediately; (b) to gnaw off your own left
> leg.  Anyone who remembers dialogue, or the names of characters, must
> obviously have chosen the latter route.

You must have watched a different film than I did.
I certainly wasn't bored to death, and I've watched it
three or four times now.

Russ

Re: [9fans] got a new feature: learning of resources and switching among them

[David Presotto]

> The film that our favourite OS is named after is SO, SO, BAD,

I was forced to watch, or at least ignore it, something like 50 times
in a few days.  Seanq, dmr, and manned a plan 9 booth at a trade show
many years back where it was showing continuously on a number of screens.

To make it even more surreal, the booth across from ours was putting on live
David Letterman like talk shows over and over and over again.

Amazingly enough, programming in the Microsoft world for the last month
or so gives me an odd feeling of deja vu.

Re: [9fans] got a new feature: learning of resources and switching among them

[Fco.J.Ballesteros]

> Are redirfs, badsrv, intended to do the same thing as "Plan B"?

After using Plan B and getting convinced that I wanted most of it
to be happy, I got back to my Plan A which was just to use Plan 9.
Yes, we make lots of plans here.

both programs give you

- lack of binding or connections to files. You keep them open, but
  that only goes down to redirfs. From there on, the file could be
  reopen. (Unless you ask for it, files open in write mode are not
  redirected, to avoid surprises).

- some adaptation to changes in your environment. Your programs
  can start using different devices when they show up, depending
  on your preferences (as said in the configuration file).

Re: [9fans] got a new feature: learning of resources and switching among them

[Scott Schwartz]

On a related topic, it sounds like if you combined this with Ken Birman's
old Isis stuff (which implemented causal group multicast) we could have
build highly available 9p services.  (I guess that sort of thing was
more popular in the days when NFS servers crashed frequently.)

Re: [9fans] got a new feature: learning of resources and switching among them

[Fco.J.Ballesteros]

> On a related topic, it sounds like if you combined this with Ken Birman's
> old Isis stuff (which implemented causal group multicast) we could have
> build highly available 9p services.  (I guess that sort of thing was
> more popular in the days when NFS servers crashed frequently.)

I think that'd be an overkill. Replica works fine for me (although
I'd like to add a new replica program to propagate changes as they're
made).

Re: [9fans] got a new feature: learning of resources and switching among them

[Andrew Simmons]

> Amazingly enough, programming in the Microsoft world for the last month
> or so gives me an odd feeling of deja vu.

Could you expand on this? Is there perhaps a movie called "Abort, retry,
fail, from Redmond" that I should see?

Re: [9fans] got a new feature: learning of resources and switching among them

[Andrew Simmons]

>>  it richly deserves the title of the "Worst Film Ever Made"

>You have to see every movie ever made before you can bestow that title

No you don't. You just have to watch "The Garden of the Finzi-Continis"
once.

Re: [9fans] got a new feature: learning of resources and switching among them

[Keith Nash]

> It is one of the most entertaining I've ever seen.

OK, I give in: I'll attempt to watch it again next time it's on TV.  How many layers of ironic detachment do I need to insert, in order to be entertained?

Re: [9fans] got a new feature: learning of resources and switching among them

[Keith Nash]

> You must have watched a different film than I did.
> I certainly wasn't bored to death, and I've watched it three or four times now.

Hmm.  I switched the film off after 5 minutes, having concluded that it richly deserves the title of the "Worst Film Ever Made".  Perhaps it gets better later on...

BTW, how many limbs have you got left?

Re: [9fans] got a new feature: learning of resources and switching among them

[rob pike, esq.]

>  it richly deserves the title of the "Worst Film Ever Made"

You have to see every movie ever made before you can bestow that title,
let alone "richly".

It is one of the most entertaining I've ever seen.

-rob

Re: [9fans] got a new feature: learning of resources and switching among them

[Dan Cross]

The inimitable Rob Pike writes:
>  It is one of the most entertaining I've ever seen.

Let's see; alien invaders use reanimated zombies to try and take over
the earth.  *Right*.  You just find it entertaining because....

``You're stupid!  Stupid! Stupid! Stupid!''

Sorry, I couldn't resist.

	- Dan C.

Re: [9fans] got a new feature: learning of resources and switching among them

[Russ Cox]

The quote is ``You see? You see? Your stupid minds... stupid! Stupid!!''

Re: [9fans] got a new feature: learning of resources and switching among them

[Dan Cross]

In article <de0dc7af7473498de1097a86e6cc729f@plan9.bell-labs.com> you write:
>The quote is ``You see? You see? Your stupid minds... stupid! Stupid!!''

Ehh, close enough for engineering work.

Interestingly, the weapon the aliens were so afraid of us (humans)
discovering was, if I recall correctly, called the Solamite.  That name
is pretty close to one of the greatest moviess to come out of the late
1960's, early 1970's era: Dolemite.

Coincidence?  I think not.

	- Dan C.

Re: [9fans] got a new feature: learning of resources and switching among them

[okamoto]

>The aim of badsrv/redirfs is to
> do that in a more automated way.

Yeah, I got it.
I love such automatic way, because we have to give our
students (not computer science, but geology :-) lots of infos
other than computer etc.  We have only limited time as we 
know though.

Kenji

Re: [9fans] got a new feature: learning of resources and switching among them

[okamoto]

Can we see it as a simple mechanism for inport/export command?
I have some problem when we must use more than, say, four CDROMs
for students, however, we have only one for it.   Then, I put the CDROM
on a mechine, and all the other students share the one CDROM by a
simple command of redirfs and badsrv?

If so, I think it's very very useful for us.

Kenji

Re: [9fans] got a new feature: learning of resources and switching among them

[Fco.J.Ballesteros]

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It can be used that way. Although if your setting is always the
same you can use just import. The aim of badsrv/redirfs is to
do that in a more automated way.

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From: okamoto@granite.cias.osakafu-u.ac.jp
To: 9fans@cse.psu.edu
Subject: Re: [9fans] got a new feature: learning of resources and switching among them
Date: Mon, 27 Jan 2003 10:31:11 +0900
Message-ID: <92abb95b592714150f61866f25b41648@granite.cias.osakafu-u.ac.jp>

Can we see it as a simple mechanism for inport/export command?
I have some problem when we must use more than, say, four CDROMs
for students, however, we have only one for it.   Then, I put the CDROM
on a mechine, and all the other students share the one CDROM by a
simple command of redirfs and badsrv?

If so, I think it's very very useful for us.

Kenji

Re: [9fans] got a new feature: learning of resources and switching among them

[Boyd Roberts]

Did anyone (anywhere) ever implement the Resource Location Protocol?

    ftp://ftp.rfc-editor.org/in-notes/rfc887.txt

Re: [9fans] got a new feature: learning of resources and switching among them

[Fco.J.Ballesteros]

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There are several (if not many) projects doing resource
discovery. One that I like has been implemented at uiuc.edu
by the srg group. The protocol badsrv is using is very
naive and will be replaced. The code used now is just enough
to get everything else working.

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From: Boyd Roberts <boyd@strakt.com>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] got a new feature: learning of resources and switching among them
Date: Mon, 27 Jan 2003 12:47:02 +0100
Message-ID: <3E351C36.8090305@strakt.com>

Did anyone (anywhere) ever implement the Resource Location Protocol?

    ftp://ftp.rfc-editor.org/in-notes/rfc887.txt

Re: [9fans] got a new feature: learning of resources and switching among them

[Jack Johnson]

Boyd Roberts wrote:
> Did anyone (anywhere) ever implement the Resource Location Protocol?
> 
>    ftp://ftp.rfc-editor.org/in-notes/rfc887.txt

I'm not certain, but it's functionally similar to a half-dozen other 
protocols, such as Service Location Protocol ( 
http://www.faqs.org/rfcs/rfc2165.html ) which I think only Sun and Apple 
ever put into use, and then Apple abandoned for multicast DNS ( 
http://www.multicastdns.org/ ) and DNS Service Discovery ( 
http://www.dns-sd.org/ ).

Are you thinking RLP would be a particularly good marriage with Plan 9, 
or just curious?

-J

Re: [9fans] got a new feature: learning of resources and switching among them

[Boyd Roberts]

Jack Johnson wrote:

> Are you thinking RLP would be a particularly good marriage with Plan 
> 9, or just curious? 

I just thought I'd throw it in.  I nearly used it 10 years back, but didn't.

[9fans] got a new feature: learning of resources and switching among them

[Fco.J.Ballesteros]

Hi,

	I'm happy enough with the behaviour of this thing and would
love to know what you think of it and any suggestion you may have.  I'll
put the code in sources soon (once that it has been exercised for
some more time).

It's a couple of programs, badsrv and redirfs.  The first one runs a
kind of discovery protocol using constraints/properties to determine
which resources are of interest for you and which ones are not.  The
second one is a file server that permits the user to switch at run
time between different file trees.  It can be instructed by means of the
first program to learn for alternate file trees for a resource.

I have been using this to redirect audio output from one machine to
another without even stopping the player, and also to switch to an
alternate home directory if the current one is no longer available
(without restarting acme).

I'm sorry about the size of the mail, but here are the manual pages
for the programs.

Anyone would want to use such thing?
Other comments? 

thanks a lot

     NAME
          redirfs - File server to redirect fids from one tree to
          another

     SYNOPSIS
          redirfs [ -abcdiCD ] [ -s srv ] [ -m mnt ] dir

     DESCRIPTION
          Redirfs is a  server that mounts itself between an existing
          directory and the user.  It learns of alternate trees for
          that directory and permits the user to change the one used.
          It can be used to dinamically redirect audio, failover from
          one file server to another, choose a cdrom depending on the
          ones available, and similar tasks.

          Redirfs works in combination with badsrv(8) because that
          program can learn by itself which resources are available
          and instruct redirfs about alternate trees.  The user relies
          on the commands file serviced by redirfs to select the pre-
          ferred tree. It is suggested to use different redirfs
          instances for different resources because the current imple-
          mentation is not multithreaded and admits only a request at
          a time.

     EXAMPLE
          This exports the local audio device and discovers new audio
          devices of interest (as dictated by the configuration file
          of badsrv):

               redirfs  -s audio '#A'
               badsrv &

          Once started, this permits the selection of a different
          audio device serviced by atlantis:

               con -C /srv/audio.cmd
               % Set audio!atlantis
               %

     SEE ALSO
          badsrv(8)

     SOURCE
          /sys/src/cmd/redirfs.c

     BUGS
          This is still experimental. This page does not show the
          options available nor the commands available in the console.

     NAME
          badsrv - Broadcast based advertising service for resources

     SYNOPSIS
          badsrv [ -v ] [ -c cfg ] [ -s srv ]

     DESCRIPTION
          Badsrv is a  server that runs a broadcast based resource
          discovery protocol to inform redirfs(4) as resources come
          and go in the network.

          The protocol is very naive, but enough for a network of mod-
          erated size: It send a broadcast to announce local resources
          every few seconds. All servers receiving a broadcast reply
          to the sender to announce their own ones. If a resource
          announce is not seen in three rounds, it is garbage col-
          lected and declared as gone.

          For each resource that is either new or collected, an appro-
          priate message is sent to the control file of the redirfs in
          charge for the resource. The convention is that the same
          resource uses the same name both in redirfs and in badsrv.

          Option -v shows debug information.

          Option -c instructs badsrv to use cfg as its configuration
          file. By default the configuration is at file
          badconf.sysname.

          Option -s posts a file at srv(3) where more configuration
          commands can be sent at run time.

          The configuration file includes commands, one per line, that
          determine a resource to be announced or a resource wanted.
          Announces for unwanted resources are ignored. Each command
          has arguments using tab as a delimiter. For example,

               ad   atlantis  cdrom     L126 #S/sdC1

          announces a resource cdrom serviced by atlantis whose loca-
          tion is room 126. The file at atlantis for the cdrom is
          #S/sdC1.

               want -    audio     L126

          tells the server to pay attention to any announce for the
          resource audio if its location is at room 126.

          The constraint (eg. L126) can be more complex like in
          Tcd!Dgsyc!L126. It is made of members separated by "!",
          where the first character refers to a property (type,
          domain, location, etc.) and the following ones identify the
          value for the property. The user can define any desired
          property/value pairs. If the properties wanted do not match
          the ones offered, the announce is ignored.

     SEE ALSO
          redirfs(4)

     SOURCE
          /sys/src/cmd/badsrv

     BUGS
          This is still experimental. User interface is missing.

Re: [9fans] got a new feature: learning of resources and switching among them

[Axel Belinfante]

> Anyone would want to use such thing?

I would like to play with it! :-)
(and see if I can even further confuse my colleagues :-)

It would be fun to see it redirect audio output from our
``coffee room plan 9 music server'' to the bitsy, and maybe
even to the sun on my desk where I use plan 9 via drawterm(*).

Hmm... could the same/something similar also be
used for a (e.g.) sound broadcasting service?
(like: send sound bytes not to one (either this or that)
 device, but to both, or all of them, or...)

(*) Via some crockery I send sound bytes from the cpu
server via drawterm to the audio device of the sun.)

Axel.

Re: [9fans] got a new feature: learning of resources and switching among them

[FJ Ballesteros]

> (and see if I can even further confuse my colleagues :-)


I implemented it because I think Plan 9 is just too simple and
wanted to get it complex.(*)


> Hmm... could the same/something similar also be
> used for a (e.g.) sound broadcasting service?
> (like: send sound bytes not to one (either this or that)
>  device, but to both, or all of them, or...)


It's more a point to point thing, since the common protocol is
9p. ads and redirections just let you plug the things together.


> (*) Via some crockery I send sound bytes from the cpu
> server via drawterm to the audio device of the sun.)
> 


The plan is actually to write some drivers in Linux and change u9fs
to let Linux export resources for us an also make it think that some
of our little trees are /dev things. But don't hold your breath :-)


---
(*) Kidding here, even if you did not think so.

Re: [9fans] got a new feature: learning of resources and switching among them

[Axel Belinfante]

> > (*) Via some crockery I send sound bytes from the cpu
> > server via drawterm to the audio device of the sun.)
> 
> The plan is actually to write some drivers in Linux and change u9fs
> to let Linux export resources for us an also make it think that some
> of our little trees are /dev things. But don't hold your breath :-)

Currently, I'm using drawterm under solaris.
In solaris I just have two named pipes /tmp/dev/^(audio volume)
that in drawterm are visible as /mnt/term/tmp/dev/^(audio volume) .
In drawterm I then just ``bind -a /mnt/term/tmp/dev /dev''.
Under solaris I run two programs, one to copy sound bytes from
/tmp/dev/audio to /dev/audio, and another to interpret lines read
from /tmp/dev/volume to update the master volume via /dev/audioctl
(currently, I also need/use sox to put in the solaris audio header,
 because I somehow cannot get the copying program to do that right).
Of course, this only works in one direction
(audio output from plan9 to solaris).

I think I would prefer to see such functionality somehow integrated
in (or connected to) drawterm, in the same way as drawterm makes
other devices available to plan 9, over something that uses u9fs --
but maybe I'm overlooking something.
I assume, a problem of audio will be that a ``host driver''
probably will be pretty machine (o.s.) dependent.
Just some thoughts.

Axel.

Re: [9fans] got a new feature: learning of resources and switching among them

[Russ Cox]

It's worth pointing out that the Windows drawterm
at one point provided a /dev/audio, though that 
version never made it into the distribution.

I want to build a more modular drawterm eventually.

Russ

Re: [9fans] got a new feature: learning of resources and switching among them

[Axel Belinfante]

> I want to build a more modular drawterm eventually.

Cool.

Please don't read my previous post as criticism on current drawterm --
I think it's pretty neat that it allows the simple named pipe trick
(crock or not) to work, and that it gets me as far as it does!

Axel.

Re: [9fans] got a new feature: learning of resources and switching among them

[Skip Tavakkolian]

> I want to build a more modular drawterm eventually.

Would something like Inferno's '#C' device and 'os' command be useful
for drawterm?  Access to local devices could then be provided through
native helper programs.  I vaguely recall Forsyth mentioning this
approach several years ago to handle things like interfacing to
proprietary codecs.

~~~~~~~~~~~
Skip Tavakkolian -- Asistant Chief Associate VP for Title Planning
9Netics - Distributed Applications Platform
http://www.9netics.com

Re: [9fans] got a new feature: learning of resources and switching among them

[Fco.J.Ballesteros]

> I think I would prefer to see such functionality somehow integrated
> in (or connected to) drawterm, in the same way as drawterm makes
> other devices available to plan 9, over something that uses u9fs --
> but maybe I'm overlooking something.

If you do it that way, linux binaries can't use
a resource serviced by Plan 9. I'd like not just to use their resources,
but also to let them use ours.

Re: [9fans] got a new feature: learning of resources and switching among them

[Skip Tavakkolian]

>                redirfs  -s audio '#A'
>                badsrv &
> 
>           Once started, this permits the selection of a different
>           audio device serviced by atlantis:
> 
>                con -C /srv/audio.cmd
>                % Set audio!atlantis
>                %

So, it should work for mice too, like this:

redirfs -s mouse '#m'

and then

con -C /srv/mouse.cmd
% Set mouse!nemosterm	# mouse input comes from nemo's
% Set mouse!skipsterm	# later from skip's

right?

How easy would it be to add a fan-out feature, perhaps only honoring
the write requests?

~~~~~~~~~~~
Skip Tavakkolian  -- Chief cook and bottle washer
9Netics - Distributed Applications Platform
http://www.9netics.com

Re: [9fans] got a new feature: learning of resources and switching among them

[Jack Johnson]

Skip Tavakkolian wrote:
> redirfs -s mouse '#m'
> con -C /srv/mouse.cmd
> % Set mouse!nemosterm	# mouse input comes from nemo's
> % Set mouse!skipsterm	# later from skip's

Are you the April Fool's Day advance team?

I'm waiting for this to devolve into a script to ensure that 
This_Is_The_Song_That_Never_Ends.mp3 is always playing on someone's 
terminal.  Or migrating popup ads in the next Web browser iteration.

Actually, this is very, very cool stuff.  I can't wait to try it out 
this weekend.

-Jack

Re: [9fans] got a new feature: learning of resources and switching among them

[FJ Ballesteros]

I'd prefer to use it for at least one more week or so before publishing
it. But if you want to try it out I'll just push it into sources next
monday in its current 'alpha' state.

> Actually, this is very, very cool stuff.  I can't wait to try it out 
> this weekend.
> 
> -Jack

Re: [9fans] got a new feature: learning of resources and switching among them

[FJ Ballesteros]

Right.
In fact, the first device I tried with before getting
into the current design was the mouse. I used it to use a mouse
to control a remote rio and it worked mostly; there´s the issue
of the hardware cursor. This thing only works for stuff that is
exported as files and has no covert channels.
One of the to-do things, although far down in the
list, is to implement an alternate file tree for a window system, in
a way that would permit redirection.

Skip Tavakkolian wrote:

>>               redirfs  -s audio '#A'
>>               badsrv &
>>
>>          Once started, this permits the selection of a different
>>          audio device serviced by atlantis:
>>
>>               con -C /srv/audio.cmd
>>               % Set audio!atlantis
>>               %
>>
> 
> So, it should work for mice too, like this:
> 
> redirfs -s mouse '#m'
> 
> and then
> 
> con -C /srv/mouse.cmd
> % Set mouse!nemosterm	# mouse input comes from nemo's
> % Set mouse!skipsterm	# later from skip's
> 
> right?
> 
> How easy would it be to add a fan-out feature, perhaps only honoring
> the write requests?
> 
> ~~~~~~~~~~~
> Skip Tavakkolian  -- Chief cook and bottle washer
> 9Netics - Distributed Applications Platform
> http://www.9netics.com
> 
> 

Re: [9fans] how to avoid a memset() optimization

[Fco.J.Ballesteros]

If you are so in hurry for cycles, you'd better wait for
six months or so and buy the next generation processor.

IMHO, human time is the most expensive resource most of
the times; so, I'd optimize that instead.

Re: [9fans] how to avoid a memset() optimization

[Scott Schwartz]

| If you are so in hurry for cycles, you'd better wait for
| six months or so and buy the next generation processor.

You want me to wait six months because I'm in a hurry?  :-)

| IMHO, human time is the most expensive resource most of
| the times; so, I'd optimize that instead.

Yes, that's the argument for an optimizing compiler: so that the machine
can quicky do the correctness preserving mechanical improvements instead
of me doing them slowly and wrongly.