When is this RT Linux orgasim going to end?

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Kevin Stallard

When is this RT Linux orgasim going to end?

Post by Kevin Stallard » Wed Oct 30, 2002 3:10 am

This is your brain.

This is your brain on RT linux.

I didn't use pictures because they would be too graphic.

The number of people thinking about using RT linux in their next projects is
much higher than I would have expected. The problems with it are so obvious
that it is a wonder why people aren't running from it.

The people who use RT linux successfully must be really good engineers, my
hat is off to them...but why use it? I don't get it....

This link was on OS news as of today (Tuesday October 29th, 2002)

http://www.windowsfordevices.com./artic ... 35685.html


Kevin

Kevin Stallard

Re: When is this RT Linux orgasim going to end?

Post by Kevin Stallard » Wed Oct 30, 2002 3:33 am

Hmmm...how did I miss that....they are talking about embedded linux, nothing
about real-time there....

I have talked to some engineers and they are _so_ ready to try RT linux. I
mean it's like salvation to them. You should see their eyes when they talk
about it. It's kind of spooky ;)

Kevin

"Kevin Stallard" <kevin@ffflyingrobots.com> wrote in message
news:apni88$q9i$1@inn.qnx.com...
This is your brain.

This is your brain on RT linux.

I didn't use pictures because they would be too graphic.

The number of people thinking about using RT linux in their next projects
is
much higher than I would have expected. The problems with it are so
obvious
that it is a wonder why people aren't running from it.

The people who use RT linux successfully must be really good engineers, my
hat is off to them...but why use it? I don't get it....

This link was on OS news as of today (Tuesday October 29th, 2002)

http://www.windowsfordevices.com./artic ... 35685.html


Kevin



ed1k

Re: When is this RT Linux orgasim going to end?

Post by ed1k » Wed Oct 30, 2002 5:46 am

"Kevin Stallard" <kevin@ffflyingrobots.com> wrote in message
news:apnjiq$rir$1@inn.qnx.com...
Hmmm...how did I miss that....they are talking about embedded linux,
nothing
about real-time there....
Thanks Kevin. Very interesting picture. Funny to compare next/current ratio
for different OSes... FreeBSD is a leader and QNX isn't last one :) And
real-time... what's real-time now? nobody care of real-time because there
are lots of cheap and fast CPU now... but embedded it's still something...

Cheers,
Eduard.

Rennie Allen

Re: When is this RT Linux orgasim going to end?

Post by Rennie Allen » Wed Oct 30, 2002 7:44 am

Kevin Stallard wrote:
Realtime doesn't mean "real-fast" and it can apply to a lot more than just
device control. Douglas Jensen has some interesting things to say on the
subject. See http://www.real-time.org/preview/introduction.htm
Exactly. Our payroll system is actually the real-time
system that matters most to me personally, even though
we make industrial controllers :-) It hasn't missed a
deadline yet, even though it doesn't run on a real-time
O/S.

In a very tangential way, I am trying to make the point
that speed *does* matter in practice. The payroll
systems constraints are so weak, that it can run
successfully, even though there are no guarantees in
the software design with regards to time. In theory
the payroll system is not real-time because I can
not prove that it will deliver my check every two
weeks (since the software offers no temporal
guarantees); yet in the real world it does deliver my
check deterministically, due mostly to the fact that
it has such a small amount of work to do in such a
very large time (computationally, our whole companies
payroll is probably no more challenging than what the
QNX scheduler does every time it gets called on a
moderately loaded system).

OTOH, the idea that because chips are so fast, that
deterministic scheduling doesn't matter is also a
fallacy (at least if you intend to produce a system
where there isn't an immense divergence between
temporal constraints, and the amount of work to be
performed within those constraints).

Rennie Allen

Re: When is this RT Linux orgasim going to end?

Post by Rennie Allen » Wed Oct 30, 2002 7:52 am

Kris Warkentin wrote:
Just because they SAY they're going to do their next project with some OS,
doesn't mean that they will. Many of them will not have done enough
in-depth evaluation to really know if it's doable or they'll just try
anyway, fail, and then go off crying to the nearest RTOS vendor.
The scary thing about Linux calling itself an RTOS is that
when people fail (and they will), some portion of them will
not go running off crying to an RTOS vendor, but will instead
conclude that commercial RTOS's are a boondoggle, concede to
the EE's, and write to the metal (I have seen this happen).

ps: no offense intended toward EE's, but you know the type
to which I refer (the hardware engineer that views
software as some sort of infection that his hardware
develops after he releases it into the wild).

Dmitri Ivanov

Re: When is this RT Linux orgasim going to end?

Post by Dmitri Ivanov » Wed Oct 30, 2002 1:33 pm

Thanks Kevin. Very interesting picture. Funny to compare next/current
ratio
for different OSes... FreeBSD is a leader and QNX isn't last one :) And
real-time... what's real-time now? nobody care of real-time because there
are lots of cheap and fast CPU now... but embedded it's still something...
What's embedded then? Memories are chip, flash disks has IDE interface,
CPUs are fast - why not put Windows NT inside your stereo? ;)

Kevin Stallard

Re: When is this RT Linux orgasim going to end?

Post by Kevin Stallard » Wed Oct 30, 2002 1:46 pm

Realtime doesn't mean "real-fast" and it can apply to a lot more than just
device control. Douglas Jensen has some interesting things to say on the
subject. See http://www.real-time.org/preview/introduction.htm

Kevin

"ed1k" <ed1k@nobody.fools.ca> wrote in message
news:apnrhg$691$1@inn.qnx.com...
"Kevin Stallard" <kevin@ffflyingrobots.com> wrote in message
news:apnjiq$rir$1@inn.qnx.com...
Hmmm...how did I miss that....they are talking about embedded linux,
nothing
about real-time there....

Thanks Kevin. Very interesting picture. Funny to compare next/current
ratio
for different OSes... FreeBSD is a leader and QNX isn't last one :) And
real-time... what's real-time now? nobody care of real-time because there
are lots of cheap and fast CPU now... but embedded it's still something...

Cheers,
Eduard.


Kris Warkentin

Re: When is this RT Linux orgasim going to end?

Post by Kris Warkentin » Wed Oct 30, 2002 2:32 pm

Just because they SAY they're going to do their next project with some OS,
doesn't mean that they will. Many of them will not have done enough
in-depth evaluation to really know if it's doable or they'll just try
anyway, fail, and then go off crying to the nearest RTOS vendor.

cheers,

Kris

"Kevin Stallard" <kevin@ffflyingrobots.com> wrote in message
news:apni88$q9i$1@inn.qnx.com...
This is your brain.

This is your brain on RT linux.

I didn't use pictures because they would be too graphic.

The number of people thinking about using RT linux in their next projects
is
much higher than I would have expected. The problems with it are so
obvious
that it is a wonder why people aren't running from it.

The people who use RT linux successfully must be really good engineers, my
hat is off to them...but why use it? I don't get it....

This link was on OS news as of today (Tuesday October 29th, 2002)

http://www.windowsfordevices.com./artic ... 35685.html


Kevin



Kris Warkentin

Re: When is this RT Linux orgasim going to end?

Post by Kris Warkentin » Wed Oct 30, 2002 3:03 pm

I read recently somewhere that software is a tool to find defects in
hardware and that hardware is a device to expose weaknesses in software.

;-)

Kris

"Rennie Allen" <rallen@csical.com> wrote in message
news:3DBF8FA6.3040401@csical.com...
Kris Warkentin wrote:
Just because they SAY they're going to do their next project with some
OS,
doesn't mean that they will. Many of them will not have done enough
in-depth evaluation to really know if it's doable or they'll just try
anyway, fail, and then go off crying to the nearest RTOS vendor.

The scary thing about Linux calling itself an RTOS is that
when people fail (and they will), some portion of them will
not go running off crying to an RTOS vendor, but will instead
conclude that commercial RTOS's are a boondoggle, concede to
the EE's, and write to the metal (I have seen this happen).

ps: no offense intended toward EE's, but you know the type
to which I refer (the hardware engineer that views
software as some sort of infection that his hardware
develops after he releases it into the wild).

Kris Warkentin

Re: When is this RT Linux orgasim going to end?

Post by Kris Warkentin » Wed Oct 30, 2002 3:06 pm

Ah...found it. Someone posted a humorous list internally that included this
section:

HARDWARE/SOFTWARE PARADIGM:
A program is a device to show up hardware faults; hardware is the
equipment used to show up software faults.
A bad workman blames his tools; a Systems Analyst chooses from: the
hardware, the software, the manual, the operating system, the interface,
the peripherals, the ambient temperature, the night shift, the day
shift, operators, programmers, BT, Mercury, the customer's
specification, fluctuations in the power supply, those Taiwan chips,
that last pint with the supplier's sales engineer

cheers,

Kris

"Kris Warkentin" <kewarken@qnx.com> wrote in message
news:apos8a$2vt$1@nntp.qnx.com...
I read recently somewhere that software is a tool to find defects in
hardware and that hardware is a device to expose weaknesses in software.

;-)

Kris

"Rennie Allen" <rallen@csical.com> wrote in message
news:3DBF8FA6.3040401@csical.com...
Kris Warkentin wrote:
Just because they SAY they're going to do their next project with some
OS,
doesn't mean that they will. Many of them will not have done enough
in-depth evaluation to really know if it's doable or they'll just try
anyway, fail, and then go off crying to the nearest RTOS vendor.

The scary thing about Linux calling itself an RTOS is that
when people fail (and they will), some portion of them will
not go running off crying to an RTOS vendor, but will instead
conclude that commercial RTOS's are a boondoggle, concede to
the EE's, and write to the metal (I have seen this happen).

ps: no offense intended toward EE's, but you know the type
to which I refer (the hardware engineer that views
software as some sort of infection that his hardware
develops after he releases it into the wild).


Bill Caroselli (Q-TPS)

Re: When is this RT Linux orgasim going to end?

Post by Bill Caroselli (Q-TPS) » Wed Oct 30, 2002 6:02 pm

I worked for a company in gaming that switched to RT Linux (against my
advice). They spent 2 to 3 man years just trying to develop features that
are free out of the box with QNX, like a reliable timer.

They finally got their product to market, but Linux still plagues them. I'm
glad I left them.

"Kevin Stallard" <kevin@ffflyingrobots.com> wrote in message
news:apni88$q9i$1@inn.qnx.com...
This is your brain.

This is your brain on RT linux.

I didn't use pictures because they would be too graphic.

The number of people thinking about using RT linux in their next projects
is
much higher than I would have expected. The problems with it are so
obvious
that it is a wonder why people aren't running from it.

The people who use RT linux successfully must be really good engineers, my
hat is off to them...but why use it? I don't get it....

This link was on OS news as of today (Tuesday October 29th, 2002)

http://www.windowsfordevices.com./artic ... 35685.html


Kevin



Bill Caroselli (Q-TPS)

Re: When is this RT Linux orgasim going to end?

Post by Bill Caroselli (Q-TPS) » Wed Oct 30, 2002 6:06 pm

"Dmitri Ivanov" <ivdal@yahoo.com> wrote in message
news:apomn4$5jl$1@inn.qnx.com...
What's embedded then? Memories are chip, flash disks has IDE interface,
CPUs are fast - why not put Windows NT inside your stereo? ;)
You don't have NT in your stereo?

Mine crashes every time I play "In A Godda Da Vida", baby.

Bill Caroselli (Q-TPS)

Re: When is this RT Linux orgasim going to end?

Post by Bill Caroselli (Q-TPS) » Wed Oct 30, 2002 6:09 pm

"Kevin Stallard" <kevin@ffflyingrobots.com> wrote in message
news:apong7$6dc$1@inn.qnx.com...
Realtime doesn't mean "real-fast" and it can apply to a lot more than just
device control. Douglas Jensen has some interesting things to say on the
subject. See http://www.real-time.org/preview/introduction.htm
Real-time is a crappy term. Deterministic is better.

If I can't reliably count the number of machine cycles (no matter how big
the number may be) between an event and the reaction to the event, then it
ain't real-time or deterministic.

Mario Charest

Re: When is this RT Linux orgasim going to end?

Post by Mario Charest » Wed Oct 30, 2002 6:41 pm

"Bill Caroselli (Q-TPS)" <QTPS@EarthLink.net> wrote in message
news:app64p$msk$1@inn.qnx.com...
I worked for a company in gaming that switched to RT Linux (against my
advice). They spent 2 to 3 man years just trying to develop features that
are free out of the box with QNX, like a reliable timer.
i wouldn't use any of these OS for gaming machines ;-)
They finally got their product to market, but Linux still plagues them.
I'm
glad I left them.

"Kevin Stallard" <kevin@ffflyingrobots.com> wrote in message
news:apni88$q9i$1@inn.qnx.com...
This is your brain.

This is your brain on RT linux.

I didn't use pictures because they would be too graphic.

The number of people thinking about using RT linux in their next
projects
is
much higher than I would have expected. The problems with it are so
obvious
that it is a wonder why people aren't running from it.

The people who use RT linux successfully must be really good engineers,
my
hat is off to them...but why use it? I don't get it....

This link was on OS news as of today (Tuesday October 29th, 2002)

http://www.windowsfordevices.com./artic ... 35685.html


Kevin





Bill Caroselli (Q-TPS)

Re: When is this RT Linux orgasim going to end?

Post by Bill Caroselli (Q-TPS) » Wed Oct 30, 2002 7:12 pm

Does "these" include QNX. We used QNX4 very successfully.

"Mario Charest" <postmaster@127.0.0.1> wrote in message
news:app8p9$pl0$1@inn.qnx.com...
"Bill Caroselli (Q-TPS)" <QTPS@EarthLink.net> wrote in message
news:app64p$msk$1@inn.qnx.com...
I worked for a company in gaming that switched to RT Linux (against my
advice). They spent 2 to 3 man years just trying to develop features
that
are free out of the box with QNX, like a reliable timer.

i wouldn't use any of these OS for gaming machines ;-)

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