When is this RT Linux orgasim going to end?

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./articles/AT7814535685.html


Kevin

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 :wink:

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./articles/AT7814535685.html


Kevin
\

“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 :slight_smile: 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.

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 :slight_smile: 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).

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).

Thanks Kevin. Very interesting picture. Funny to compare next/current
ratio
for different OSes… FreeBSD is a leader and QNX isn’t last one > :slight_smile: > 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? :wink:

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 > :slight_smile: > 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.

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./articles/AT7814535685.html


Kevin
\

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.

:wink:

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).

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.

:wink:

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).

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./articles/AT7814535685.html


Kevin
\

“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? > :wink:

You don’t have NT in your stereo?

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

“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.

“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 :wink:

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./articles/AT7814535685.html


Kevin


\

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 > :wink:

“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

Thanks Kevin for the yet another interesting link. I never heard name
Douglas Jensen, but I agree with his point. Also I’ve read some articles
about real-time at QSSL website. I remember one of them was really
scientific like… and probably real-time for me it’s something what’s
called hard real-time. Ok. Where I said “real-fast”? For example, take a
look at Dedicated System’s report QNX vs WinCE… and, for example, at such
important parameter as interrupt latency. What do you see? WinCE sometimes
in ten times slower than QNX. So, you’re yelloing it’s not real-time, it’s
not predictable… It’s true for equal boards. Then take the board ten times
faster with WinCE. What do you see? It’s mainly faster then you need, but
worst case is good for you. In many cases, you have limited time to do a
task, but you don’t care if task is calculated faster. Mostly important for
real-time is the maximal time which you need to spend for calculation in
order to not be flooded by input data stream. And second important parameter
for real-time is the delay between input data and well calculated output
data, because the data might be not actual (expired data). So, real-time is
not “real-fast”. It’s “real-predictable_fast”… IMHO.
Also, I know about excellent system architecture of QNX, about lots of
problems concerning all another OS… It’s not a start of such discussion, I
hope.

Thanks everybody,
Eduard.

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 > :slight_smile: > 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.

\

“Dmitri Ivanov” <ivdal@yahoo.com> wrote in message
news:apomn4$5jl$1@inn.qnx.com

Thanks Kevin. Very interesting picture. Funny to compare next/current
ratio
for different OSes… FreeBSD is a leader and QNX isn’t last one > :slight_smile: > 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?

I guess it’s some tools like mkifs… maybe, some support of specific
hardware… eh… something like touch-screen… Or in other words, something
like LEGO.

Memories are chip, flash disks has IDE interface,
CPUs are fast - why not put Windows NT inside your stereo? > :wink:

Right now I have no computer… I have no even stereo… But good idea!
Excellent! I will try to put NT inside of my old “Zenit” camera :slight_smile:

Eduard.


No dark sarcasm in the class-room (c)

It doesn’t matter that CE is ten times slow…as long as it is (as you say)
predictable.

There are definitely other considerations as well…but as you say, I don’t
want to get involved with such a discussion either. The point I was making
was that some will attempt to crank up the CPU so they will meet their
deadlines using bad scheduling algorithms or because of some other weakness
in the OS they are using…and I thought that was what you meant.

Somehow…I find myself, once again, having incorrectly assumed :wink:

Best Regards,
Kevin



Regards,
Kevin
“ed1k” <ed1k@nobody.fools.ca> wrote in message
news:appg8g$4r7$1@inn.qnx.com

“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

Thanks Kevin for the yet another interesting link. I never heard name
Douglas Jensen, but I agree with his point. Also I’ve read some articles
about real-time at QSSL website. I remember one of them was really
scientific like… and probably real-time for me it’s something what’s
called hard real-time. Ok. Where I said “real-fast”? For example, take a
look at Dedicated System’s report QNX vs WinCE… and, for example, at
such
important parameter as interrupt latency. What do you see? WinCE
sometimes
in ten times slower than QNX. So, you’re yelloing it’s not real-time, it’s
not predictable… It’s true for equal boards. Then take the board ten
times
faster with WinCE. What do you see? It’s mainly faster then you need, but
worst case is good for you. In many cases, you have limited time to do a
task, but you don’t care if task is calculated faster. Mostly important
for
real-time is the maximal time which you need to spend for calculation in
order to not be flooded by input data stream. And second important
parameter
for real-time is the delay between input data and well calculated output
data, because the data might be not actual (expired data). So, real-time
is
not “real-fast”. It’s “real-predictable_fast”… IMHO.
Also, I know about excellent system architecture of QNX, about lots of
problems concerning all another OS… It’s not a start of such discussion,
I
hope.

Thanks everybody,
Eduard.


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 > :slight_smile:
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.



\

“Kevin Stallard” <kevin@ffflyingrobots.com> wrote in message
news:appi1p$6sa$1@inn.qnx.com

It doesn’t matter that CE is ten times slow…as long as it is (as you
say)
predictable.

There are definitely other considerations as well…but as you say, I
don’t
want to get involved with such a discussion either. The point I was
making
was that some will attempt to crank up the CPU so they will meet their
deadlines using bad scheduling algorithms or because of some other
weakness
in the OS they are using…and I thought that was what you meant.

Yes, you’re right. Just now I’m looking for a job in Toronto and it’s very
funny nobody know QNX here. Maybe, I visited wrong places… I got feeling
the QNX is more popular in Ukraine LOL! They’re telling/writting here about
mission critical, real-time and Linux… best case I heard VxWorks :slight_smile:

Cheers,
Eduard.


JAZZ has a sense of Humor (c)

Somehow…I find myself, once again, having incorrectly assumed > :wink:

Best Regards,
Kevin

“Bill Caroselli (Q-TPS)” <QTPS@EarthLink.net> wrote in message
news:appa9f$rp7$1@inn.qnx.com

Does “these” include QNX. We used QNX4 very successfully.

Yes “these” includes QNX. The fact that you use it doesn’t change that I
wouldn’t :wink:

  • Mario