[9fans] Twente '9con -- some photos

[9fans] Twente '9con -- some photos

[boyd, rounin]

http://www.insultant.net/nl/2004/Twente9con
--
MGRS 31U DQ 52572 12604

Re: [9fans] Twente '9con -- some photos

[Joseph Stewart]

Thanks for the photos... I was wondering; in the photo DSC00582.JPG,
is the device the gentleman has his coffee cup on, is that some new
hardware Plan9 has been ported to? I'd sure like to hear some detail
on this!

Happy Holidays!

-joe


On Fri, 24 Dec 2004 18:40:50 +0100, boyd, rounin <boyd@insultant.net> wrote:
> http://www.insultant.net/nl/2004/Twente9con
> --
> MGRS 31U DQ 52572 12604
> 
> 


-- 
Person who say it cannot be done should not interrupt person doing it.
 -- Old Scottish Proverb

Re: [9fans] Twente '9con -- some photos

[boyd, rounin]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 1445 bytes --]

first if using umbilical 
   cords so they won?t be tough). 
Place a slice of ham and cheese on each, along with some minced onion 
   then fold in half, trimming neatly. 
Dredge in flour, eggwash, then seasoned breadcrumbs; 
   allow to sit for a few minutes. 
Sauté in butter and olive oil until golden brown, 
   about 6 minutes on each side.



Shish Kababes

As old as the hills, this technique has employed seafood, beef, pork, lamb, 
poultry, and vegetables; just about anything can be grilled, and young humans 
are no exception!

High quality marinade (Teriyaki and garlic perhaps)
1 inch cubes of tender meat, preferably from the nursery
Onions
bell peppers
Wooden or metal skewers

Marinate the meat overnight. 
Get the grill good and hot while placing meat, vegetables, and 
   fruit such as pineapples or cherries on the skewers. 
Don?t be afraid to use a variety of meats. 
Grill to medium rare, 
   serve with garlic cous-cous and sautéed asparagus. 
Coffee and sherbet for desert then walnuts, cheese, and port. 
Cigars for the gentlemen (and ladies if they so desire)!



Crock-Pot Crack Baby

When the quivering, hopelessly addicted crack baby succumbs to death, 
get him immediately butchered and into the crock-pot, so that any 
remaining toxins will not be fatal. But don?t cook it too long, 
because like Blowfish, there is a perfect medium between the poisonous 
and the sti

Re: [9fans] Twente '9con -- some photos

[boyd, rounin]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
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Place in a large bowl and cool. 
Add seasoned breadcrumbs and a little of the tomato gravy, 
   enough to make the mixture pliable.
Divide the stuffing among the cabbage leaves then roll. 
Place seam down in a baking pan. 
Ladle tomato gravy on top, 
   and bake at 325° for 30 - 45 minutes.



Umbilical Cordon Bleu

Nothing is so beautiful as the bond between mother and child, 
so why not consume it? 
Children or chicken breasts will work wonderfully also.

4 whole umbilical chords (or baby breasts, or chicken breasts)
4 thin slices of smoked ham, and Gruyere cheese
Flour
eggwash (milk and eggs)
seasoned bread crumbs
1 onion
minced
salt
pepper
butter
olive oil

Pound the breasts flat (parboil first if using umbilical 
   cords so they won?t be tough). 
Place a slice of ham and cheese on each, along with some minced onion 
   then fold in half, trimming neatly. 
Dredge in flour, eggwash, then seasoned breadcrumbs; 
   allow to sit for a few minutes. 
Sauté in butter and olive oil until golden brown, 
   about 6 minutes on each side.



Shish Kababes

As old as the hills, this technique has employed seafood, beef, pork, lamb, 
poultry, and vegetables; just about anything can be grilled, and young humans 
are no exception!

High quality marinade (Teriyaki and garlic perhaps)
1 inch cubes of tender meat, preferably from the nursery
Onions
bell peppers
Wooden or metal skewers

Marinate the meat overnight. 
Get the grill good and hot while placing meat, vegetables, and 
   fruit such as pineap

Re: [9fans] Twente '9con -- some photos

[Axel Belinfante]

> http://www.insultant.net/nl/2004/Twente9con

some more:
http://www.cs.utwente.nl/~belinfan/Twente9con2004/

Re: [9fans] Twente '9con -- some photos

[Axel Belinfante]

I added a few more to
http://www.cs.utwente.nl/~belinfan/Twente9con2004/

Re: [9fans] Twente '9con -- some photos

[Dan Cross]

Joseph Stewart <joseph.stewart@gmail.com> writes:
> 
> Thanks for the photos... I was wondering; in the photo DSC00582.JPG,
> is the device the gentleman has his coffee cup on, is that some new
> hardware Plan9 has been ported to? I'd sure like to hear some detail
> on this!

I don't know, but I'm pretty sure it's called a `table.'  I don't think
it'll run Plan 9.  :-)

	- Dan C.

Re: [9fans] Twente '9con -- some photos

[Fco. J. Ballesteros]

That's right. We don't have many drivers.
But someone might write one in the future :-)

happy new year.

Re: [9fans] All out of GMail invites...

[John DeGood]

In case there are any stragglers, I have 6 invites: *<jdegood@gmail.com>*

Re: [9fans] Twente '9con -- some photos

[Devon H. O'Dell]

Dan Cross wrote:
> Joseph Stewart <joseph.stewart@gmail.com> writes:
> 
>>Thanks for the photos... I was wondering; in the photo DSC00582.JPG,
>>is the device the gentleman has his coffee cup on, is that some new
>>hardware Plan9 has been ported to? I'd sure like to hear some detail
>>on this!
> 
> 
> I don't know, but I'm pretty sure it's called a `table.'  I don't think
> it'll run Plan 9.  :-)
> 
> 	- Dan C.

I'm pretty sure it was a refrigerator, actually... ;)

--Devon

Re: [9fans] Twente '9con -- some photos

[Joseph Stewart]

I'll bet cooling isn't a problem on this device, then... ;-)


On Mon, 03 Jan 2005 09:46:41 +0100, Devon H. O'Dell
<dodell@sitetronics.com> wrote:
> Dan Cross wrote:
> > Joseph Stewart <joseph.stewart@gmail.com> writes:
> >
> >>Thanks for the photos... I was wondering; in the photo DSC00582.JPG,
> >>is the device the gentleman has his coffee cup on, is that some new
> >>hardware Plan9 has been ported to? I'd sure like to hear some detail
> >>on this!
> >
> >
> > I don't know, but I'm pretty sure it's called a `table.'  I don't think
> > it'll run Plan 9.  :-)
> >
> >       - Dan C.
> 
> I'm pretty sure it was a refrigerator, actually... ;)
> 
> --Devon
> 


-- 
Person who say it cannot be done should not interrupt person doing it.
 -- Old Scottish Proverb

Re: [9fans] Twente '9con -- some photos

[Axel Belinfante]

> I'll bet cooling isn't a problem on this device, then... ;-)

right. :-)

on the device under discussion there is another device:
a grey box hidden behind the oven -- you can only see the
cables leading to it on e.g.
http://www.insultant.net/nl/2004/Twente9con/DSC00582.jpg.
The grey box is linked to the plan 9 system via a parellel port.

The grey box houses a webcam (currently not connected,
 it was used until we switched to non-transparent coffee pots)
and some electronics that has the parallel port connection.

The big photo behind the sofa under the world map, e.g. in
http://www.insultant.net/nl/2004/Twente9con/DSC00585.JPG
http://www.cs.utwente.nl/~belinfan/Twente9con2004/Large0/0020.jpg
shows the insides of the grey box, and some of the people
responsible for its existence (student doing the work, supervisors).

A coffee maker receives its power via this grey box.
The electronics can measure the power consumption
of the coffee maker in some rough steps:
 - 0 watt (machine off)
 - 100 watt (keep coffee warm)
 - 2000 watt (prepare coffee)
This info is made available over the parallel port.
The electronics can also cut the power to the coffee maker
if the right command is send to the parallel port.
(to switch the coffee maker off if it has been on too long)

There is a daemon on the plan 9 machine that looks at
the parallel port and polls for the coffee maker status,
and makes it available in a small fs.

The red bar at the bottom of the screen in
http://www.insultant.net/nl/2004/Twente9con/DSC00581.JPG
is based on stats(1), it shows when coffee was being prepared.
It uses the parellport watching fs.

The info used to be made available via the web
and via some client programs on the users' desktops
but is currently not completely operational.
Older info is at http://wwwhome.cs.utwente.nl/~slurp/


The system was developed under linux. When the system (disk)
broke, a while ago, I set it up again, and moved it to plan 9 -
it was a good pretext to get a plan 9 machine up and running
as 'hobby project'. By the time I was ready to tackle (port to plan 9)
the simple image processing software that took the webcam
picture and looked in it for evidence of 100%, 75%, 50%, 25%,
10% of coffee, or no coffee, or no pot, the coffee maker was
replaced by one that uses non-transparent coffee pots
(and no longer has the small heater to keep coffee warm).
A bit later I upgraded the hardware, and the 'new' machine
no longer has the two parallel ports needed to connect
both quickcam and power consumption measuring hardware,
so the quickcam is not used currently.


Axel.

> On Mon, 03 Jan 2005 09:46:41 +0100, Devon H. O'Dell
> <dodell@sitetronics.com> wrote:
> > Dan Cross wrote:
> > > Joseph Stewart <joseph.stewart@gmail.com> writes:
> > >
> > >>Thanks for the photos... I was wondering; in the photo DSC00582.JPG,
> > >>is the device the gentleman has his coffee cup on, is that some new
> > >>hardware Plan9 has been ported to? I'd sure like to hear some detail
> > >>on this!
> > >
> > >
> > > I don't know, but I'm pretty sure it's called a `table.'  I don't think
> > > it'll run Plan 9.  :-)
> > >
> > >       - Dan C.
> > 
> > I'm pretty sure it was a refrigerator, actually... ;)

Re: [9fans] Twente '9con -- some photos

[Joseph Stewart]

How cool... and to think I was just being a smart a$$... :P


On Mon, 03 Jan 2005 16:18:22 +0100, Axel Belinfante
<Axel.Belinfante@cs.utwente.nl> wrote:
> > I'll bet cooling isn't a problem on this device, then... ;-)
> 
> right. :-)
> 
> on the device under discussion there is another device:
> a grey box hidden behind the oven -- you can only see the
> cables leading to it on e.g.
> http://www.insultant.net/nl/2004/Twente9con/DSC00582.jpg.
> The grey box is linked to the plan 9 system via a parellel port.
> 
> The grey box houses a webcam (currently not connected,
>  it was used until we switched to non-transparent coffee pots)
> and some electronics that has the parallel port connection.
> 
> The big photo behind the sofa under the world map, e.g. in
> http://www.insultant.net/nl/2004/Twente9con/DSC00585.JPG
> http://www.cs.utwente.nl/~belinfan/Twente9con2004/Large0/0020.jpg
> shows the insides of the grey box, and some of the people
> responsible for its existence (student doing the work, supervisors).
> 
> A coffee maker receives its power via this grey box.
> The electronics can measure the power consumption
> of the coffee maker in some rough steps:
>  - 0 watt (machine off)
>  - 100 watt (keep coffee warm)
>  - 2000 watt (prepare coffee)
> This info is made available over the parallel port.
> The electronics can also cut the power to the coffee maker
> if the right command is send to the parallel port.
> (to switch the coffee maker off if it has been on too long)
> 
> There is a daemon on the plan 9 machine that looks at
> the parallel port and polls for the coffee maker status,
> and makes it available in a small fs.
> 
> The red bar at the bottom of the screen in
> http://www.insultant.net/nl/2004/Twente9con/DSC00581.JPG
> is based on stats(1), it shows when coffee was being prepared.
> It uses the parellport watching fs.
> 
> The info used to be made available via the web
> and via some client programs on the users' desktops
> but is currently not completely operational.
> Older info is at http://wwwhome.cs.utwente.nl/~slurp/
> 
> The system was developed under linux. When the system (disk)
> broke, a while ago, I set it up again, and moved it to plan 9 -
> it was a good pretext to get a plan 9 machine up and running
> as 'hobby project'. By the time I was ready to tackle (port to plan 9)
> the simple image processing software that took the webcam
> picture and looked in it for evidence of 100%, 75%, 50%, 25%,
> 10% of coffee, or no coffee, or no pot, the coffee maker was
> replaced by one that uses non-transparent coffee pots
> (and no longer has the small heater to keep coffee warm).
> A bit later I upgraded the hardware, and the 'new' machine
> no longer has the two parallel ports needed to connect
> both quickcam and power consumption measuring hardware,
> so the quickcam is not used currently.
> 
> 
> Axel.
> 
> > On Mon, 03 Jan 2005 09:46:41 +0100, Devon H. O'Dell
> > <dodell@sitetronics.com> wrote:
> > > Dan Cross wrote:
> > > > Joseph Stewart <joseph.stewart@gmail.com> writes:
> > > >
> > > >>Thanks for the photos... I was wondering; in the photo DSC00582.JPG,
> > > >>is the device the gentleman has his coffee cup on, is that some new
> > > >>hardware Plan9 has been ported to? I'd sure like to hear some detail
> > > >>on this!
> > > >
> > > >
> > > > I don't know, but I'm pretty sure it's called a `table.'  I don't think
> > > > it'll run Plan 9.  :-)
> > > >
> > > >       - Dan C.
> > >
> > > I'm pretty sure it was a refrigerator, actually... ;)
> 


-- 
Person who say it cannot be done should not interrupt person doing it.
 -- Old Scottish Proverb

Re: [9fans] Twente '9con -- some photos

[Axel Belinfante]

well, if this thread had not moved (degenerated? :-)
in this direction I probably would never have posted this whole story
(could be I mentioned some of it earlier on 9fans, I don't remember) -
so thanks to all who contributed to it! :-)

Axel.

> How cool... and to think I was just being a smart a$$... :P
> 
> 
> On Mon, 03 Jan 2005 16:18:22 +0100, Axel Belinfante
> <Axel.Belinfante@cs.utwente.nl> wrote:
> > > I'll bet cooling isn't a problem on this device, then... ;-)
> > 
> > right. :-)
> > 
> > on the device under discussion there is another device:
> > a grey box hidden behind the oven -- you can only see the
> > cables leading to it on e.g.
> > http://www.insultant.net/nl/2004/Twente9con/DSC00582.jpg.
> > The grey box is linked to the plan 9 system via a parellel port.
> > 
> > The grey box houses a webcam (currently not connected,
> >  it was used until we switched to non-transparent coffee pots)
> > and some electronics that has the parallel port connection.
> > 
> > The big photo behind the sofa under the world map, e.g. in
> > http://www.insultant.net/nl/2004/Twente9con/DSC00585.JPG
> > http://www.cs.utwente.nl/~belinfan/Twente9con2004/Large0/0020.jpg
> > shows the insides of the grey box, and some of the people
> > responsible for its existence (student doing the work, supervisors).
> > 
> > A coffee maker receives its power via this grey box.
> > The electronics can measure the power consumption
> > of the coffee maker in some rough steps:
> >  - 0 watt (machine off)
> >  - 100 watt (keep coffee warm)
> >  - 2000 watt (prepare coffee)
> > This info is made available over the parallel port.
> > The electronics can also cut the power to the coffee maker
> > if the right command is send to the parallel port.
> > (to switch the coffee maker off if it has been on too long)
> > 
> > There is a daemon on the plan 9 machine that looks at
> > the parallel port and polls for the coffee maker status,
> > and makes it available in a small fs.
> > 
> > The red bar at the bottom of the screen in
> > http://www.insultant.net/nl/2004/Twente9con/DSC00581.JPG
> > is based on stats(1), it shows when coffee was being prepared.
> > It uses the parellport watching fs.
> > 
> > The info used to be made available via the web
> > and via some client programs on the users' desktops
> > but is currently not completely operational.
> > Older info is at http://wwwhome.cs.utwente.nl/~slurp/
> > 
> > The system was developed under linux. When the system (disk)
> > broke, a while ago, I set it up again, and moved it to plan 9 -
> > it was a good pretext to get a plan 9 machine up and running
> > as 'hobby project'. By the time I was ready to tackle (port to plan 9)
> > the simple image processing software that took the webcam
> > picture and looked in it for evidence of 100%, 75%, 50%, 25%,
> > 10% of coffee, or no coffee, or no pot, the coffee maker was
> > replaced by one that uses non-transparent coffee pots
> > (and no longer has the small heater to keep coffee warm).
> > A bit later I upgraded the hardware, and the 'new' machine
> > no longer has the two parallel ports needed to connect
> > both quickcam and power consumption measuring hardware,
> > so the quickcam is not used currently.
> > 
> > 
> > Axel.
> > 
> > > On Mon, 03 Jan 2005 09:46:41 +0100, Devon H. O'Dell
> > > <dodell@sitetronics.com> wrote:
> > > > Dan Cross wrote:
> > > > > Joseph Stewart <joseph.stewart@gmail.com> writes:
> > > > >
> > > > >>Thanks for the photos... I was wondering; in the photo DSC00582.JPG,
> > > > >>is the device the gentleman has his coffee cup on, is that some new
> > > > >>hardware Plan9 has been ported to? I'd sure like to hear some detail
> > > > >>on this!
> > > > >
> > > > >
> > > > > I don't know, but I'm pretty sure it's called a `table.'  I don't thi
> nk
> > > > > it'll run Plan 9.  :-)
> > > > >
> > > > >       - Dan C.
> > > >
> > > > I'm pretty sure it was a refrigerator, actually... ;)
> > 
> 
> 
> -- 
> Person who say it cannot be done should not interrupt person doing it.
>  -- Old Scottish Proverb

Re: [9fans] Twente '9con -- some photos

[boyd, rounin]

> I'm pretty sure it was a refrigerator, actually... ;)

it is.  but there's another cup -- hand held ;)

[9fans] What is...

[Vladimir Los]

What is Plan B?

Re: [9fans] What is...

[Fco. J. Ballesteros]

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The OS we are building (and using). In its
present form it's a modified Plan 9. You can
think of it as a Plan 9 that adapts to changes
in the environment and assumes that there're many
machines per user.

Feel free to ask for info, source, or whatever.
BTW, the license is the lucent one, because 90%
of the system is taken verbatim from plan 9.

http://lsub.org has more info.

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From: Vladimir Los <wlad@mipk.kharkiv.edu>
To: 9fans@cse.psu.edu
Subject: [9fans] What is...
Date: Mon, 03 Jan 2005 19:05:54 +0200
Message-ID: <41D97B72.2070403@mipk.kharkiv.edu>

What is Plan B?

Re: [9fans] What is...

[Fco. J. Ballesteros]

Hmm. Of course it could be
any other thing as well. Most people have a Plan B. :-)

Re: [9fans] What is...

[Vladimir Los]

> The OS we are building (and using). In its
> present form it's a modified Plan 9. You can
> think of it as a Plan 9 that adapts to changes
> in the environment and assumes that there're many
> machines per user.
> 
> Feel free to ask for info, source, or whatever.
> BTW, the license is the lucent one, because 90%
> of the system is taken verbatim from plan 9.

Do you coordinate your enforcements with Plan 9 team?
Is it parallel branch?
I do not understand clearly from this discussion list: Plan 9 is alive 
or is develpoped only by enthusiastic persons?

Where can I view full list of developers who create theirs new programms 
specially for Plan9?

Re: [9fans] What is...

[Fco. J. Ballesteros]

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We create patches for plan 9 when we
think that would help, and also send user programs
that we think might be of help in plan 9 as well.
But it's a parallel branch.

IMHO, Plan 9 is alive because it has users.
The difference wrt, say, Linux, is that most plan 9
users are willing to update the system software
when they feel the need for it. Also, if I'm not
mistaken, most source does not carry out the name
of the person who wrote it.  There's a list in the
papers with the names of the authors. But as of
today, other 9fans have contributed.

A search on the list archives may probably answer
think kind of question.

hth

[-- Attachment #2: Type: message/rfc822, Size: 3270 bytes --]

From: Vladimir Los <wlad@mipk.kharkiv.edu>
To: Fans of the OS Plan 9 from Bell Labs <9fans@cse.psu.edu>
Subject: Re: [9fans] What is...
Date: Mon, 03 Jan 2005 19:23:21 +0200
Message-ID: <41D97F89.3080701@mipk.kharkiv.edu>

> The OS we are building (and using). In its
> present form it's a modified Plan 9. You can
> think of it as a Plan 9 that adapts to changes
> in the environment and assumes that there're many
> machines per user.
> 
> Feel free to ask for info, source, or whatever.
> BTW, the license is the lucent one, because 90%
> of the system is taken verbatim from plan 9.

Do you coordinate your enforcements with Plan 9 team?
Is it parallel branch?
I do not understand clearly from this discussion list: Plan 9 is alive 
or is develpoped only by enthusiastic persons?

Where can I view full list of developers who create theirs new programms 
specially for Plan9?

[9fans] hello to 9fans :)

[Justin Stressman]

just joined the list. I've been following the comp.os.plan9 group for a 
week or two now... decided it was time to join the "actual" list. ;)

anyway... I have 2 Plan 9 systems running here... I'm still learning, 
setting up venti and fossil etc. looking forward to getting more 
proficient with the systems and actually being able to better understand 
and use them.

I think once I get through reading the wiki and getting more comfortable 
with the system, I'm going to try recompiling the kernel to support a 
newer radeon7000 card I picked up, so I can try some higher resolutions 
etc. In the past, I had an r3(I think?) edition install on a better box, 
with a geforce3 and it ran great, but I was in over my head at the time 
and preoccupied with other things.

anyway, I'm back and making good progress this time! just wanted to say 
"hi" :P

"Reality is that which, when you stop believing in it, doesn't go away".
                 -- Philip K. Dick

Re: [9fans] What is...

[Kenji Okamoto]

> Hmm. Of course it could be
> any other thing as well. Most people have a Plan B. :-)

I saw a phrase of "association with Plan B" in a movie in this
holiday season!   I was surprised at first, nemo is contributing
Troy?   Nemo <--> Troy,  hmm, it may be true.☺

A happy New year all 9fans.

Kenji -- just have read over 900 mails!

[9fans] RT fields applications

[Vladimir Los]

Dear plan9fans!

I have two questions.

1. How does Plan9 AND Inferno fight against processes priority inversions?

2. What are the value of "minimum system clock ticks" in Plan9 and Inferno?

Thanks.

Wlad

Re: [9fans] RT fields applications

[Bruce Ellis]

neither "fight".  the scheduler(s) are not subseptible to hype.
algorithms that work just work.

brucee

On Thu, 06 Jan 2005 11:15:17 +0200, Vladimir Los <wlad@mipk.kharkiv.edu> wrote:
> Dear plan9fans!
> 
> I have two questions.
> 
> 1. How does Plan9 AND Inferno fight against processes priority inversions?
> 
> 2. What are the value of "minimum system clock ticks" in Plan9 and Inferno?
> 
> Thanks.
> 
> Wlad
> 
>

Re: [9fans] RT fields applications

[David Tolpin]

On 06.01.2005, at 14:51, Bruce Ellis wrote:

> neither "fight".  the scheduler(s) are not subseptible to hype.
> algorithms that work just work.
>


I believe this is a language barrier, Vladimir meant 'how does Plan9 
deal with ...'

>> 1. How does Plan9 AND Inferno fight against processes priority 
>> inversions?

Re: [9fans] RT fields applications

[Vladimir Los]

Bruce Ellis wrote:

> neither "fight".  the scheduler(s) are not subseptible to hype.
> algorithms that work just work.

OK
Can you give links to the description of the scheduler of Plan9 and 
Inferno (and principles of their project decisions)? Do not even try to 
write "see sources"! :o)
Thanks.

Wlad

Re: [9fans] RT fields applications

[Vladimir Los]

David Tolpin wrote:

>>> 1. How does Plan9 AND Inferno fight against processes priority 
>>> inversions?
> I believe this is a language barrier, Vladimir meant 'how does Plan9 
> deal with ...'

Yes and No. :o)

It's from our projects. We faced situations when a low priority process 
could suspend a process having higher priority.

The only OS we know about which "deal with" such a trap is QNX.
But there are some reasons for us to pay attention to (to look at) other 
OSs for our projects. The most "whole-hearted" OSes at this moment for 
our task are Plan9 and Inferno (with special Linux and FreeBSD, 
DragonflyBSD - other members of our community (http://qnxclub.net) 
research these OSes). Yet one think does remain: "realtimity"... :o) I 
mean real time features not in mean of "market notation" but in solving 
problems I asked about...

Thank you.

Wlad

Re: [9fans] RT fields applications

[Bruce Ellis]

well no, and no.

i understood the question.  the scheduler is careful not to do
any dumb things that lead to priority inversion.  (there were
some early bugs, at least in inferno, that have been fixed.)

if the user implements some buggy scheme of managing
processes that isn't right he gets a correct result, a buggy
program, not something that is patched by a kernel hack.

how about EDF if you aren't stuck in the 80s?

brucee

Re: [9fans] RT fields applications

[Vladimir Los]

Bruce Ellis wrote:

> well no, and no.
> 
> i understood the question.  the scheduler is careful not to do
> any dumb things that lead to priority inversion.  (there were
> some early bugs, at least in inferno, that have been fixed.)
> 
> if the user implements some buggy scheme of managing
> processes that isn't right he gets a correct result, a buggy
> program, not something that is patched by a kernel hack.

This is not case of creating "buggy" schemes.

> how about EDF if you aren't stuck in the 80s?
No we are stuck in the 50s and programming with toggle switches loading 
programms bit by bit into the core bocks...
What is EDF?

Re: [9fans] RT fields applications

[Nigel Roles]

> It's from our projects. We faced situations when a low priority 
> process could suspend a process having higher priority.
>
> The only OS we know about which "deal with" such a trap is QNX.


Brucee is right. Priority inversion is a direct result of a higher 
priority process blocking
while trying to claim a resource held by a lower priority process, and 
therefore can
be considered to be a design issue. However, most COTS RTOSes implement 
priority
inheritance, where the process holding a resource has the priority of 
the highest
process blocked on the resource.

Plan 9 and Inferno do not; most processes run at the same priority.

The classical example of 'death by priority inversion' was the Mars 
PathFinder in
'97, which kept resetting while on Mars. It was running VxWorks,
which has priority inheritance, but the authors of the code had not turned
on the inheritance for the resource concerned.

Inheritance is not a universal panacea. If there is a one low priority 
process which is used
by many higher priority ones it can end up running at high priority most 
of time, making
a mockery of setting different priorities in the first place.

So, careful design is still necessary.

Re: [9fans] RT fields applications

[Bruce Ellis]

what is edf? man proc may help.

> So, careful design is still necessary.

you can bet your beer money on that.

Re: [9fans] RT fields applications

[Tiit Lankots]

> What is EDF?

Earliest Deadline First, an elegant - and in many cases effective -  
scheduling
algorithm. Oh, and there are tons of research papers on scheduling,  
including
on priority inversion and how to avoid it.

Re: [9fans] RT fields applications

[boyd, rounin]

> a couple of papers by sape et al.

yeah sape gave a great lecture at twente which
covered priority inversion and plan 9 kernel locks.

really cool.

Re: [9fans] RT fields applications

[Taj Khattra]

a couple of papers by sape et al.

http://purl.org/utwente/fid/1145
http://purl.org/utwente/fid/1149

Re: [9fans] RT fields applications

[Sape Mullender]

boyd@insultant.net:
> yeah sape gave a great lecture at twente which
> covered priority inversion and plan 9 kernel locks.
> 
> really cool.

Why, thank you very much.  Glad you liked it.  The students
got a kick out of my statement that programming is a craft, not
a science.  Just like in other crafts, like cabinet making, you learn
it by watching a master and trying it yourself.

	Sape

Re: [9fans] RT fields applications

[Bruce Ellis]

very crafty.  edf is a good tool .  and you'll certainly learn
more from a 10 minute chat with sape than a few years
of correspondence with the RT experts from purveyors of
20 year-old monoliths marketted by the big boys.
stretching the analogy a bit - you will hit yourself on the
thumb with a hammer a few times but you learn.

brucee

On Fri, 7 Jan 2005 14:25:11 -0500, Sape Mullender
<sape@plan9.bell-labs.com> wrote:
> boyd@insultant.net:
> > yeah sape gave a great lecture at twente which
> > covered priority inversion and plan 9 kernel locks.
> >
> > really cool.
> 
> Why, thank you very much.  Glad you liked it.  The students
> got a kick out of my statement that programming is a craft, not
> a science.  Just like in other crafts, like cabinet making, you learn
> it by watching a master and trying it yourself.
> 
>        Sape
> 
>

Re: [9fans] RT fields applications

[Tim Newsham]

> very crafty.  edf is a good tool .  and you'll certainly learn
> more from a 10 minute chat with sape than a few years

So are there any materials from the lecture (video, audio, notes,
slides, anything) for the rest of us?

Tim N.

Re: [9fans] RT fields applications

[Jason Gurtz]

On 1/7/2005 14:25, Sape Mullender wrote:

> Why, thank you very much.  Glad you liked it.  The students
> got a kick out of my statement that programming is a craft, not
> a science.  Just like in other crafts, like cabinet making, you learn
> it by watching a master and trying it yourself.

So true, all my classmates just don't seem to get it.  Wish I could have
seen that lecture.  It's hard to get good instruction these days; the java
folks seem to have taken over at the community college.

I'm excited now because I've convinced enough of my peers to sign up for
assembler this spring and the class won't get canceled as usual.

Cheers,

~Jason

-- 

Re: [9fans] RT fields applications

[Sape Mullender]

> So are there any materials from the lecture (video, audio, notes,
> slides, anything) for the rest of us?

Check out
	plan9.bell-labs.com/who/sape/gos
for the slides I used as well as the example application (now on sources)

	Sape