John wrote:
> Are most modern RTOS message-based operating systems? For example,
> VxWorks, or embedded linux OS? I try to understand how tasks
> communicate with each other? My understanding is that tasks can
> communicate via messages, or mails? Any other approaches?
> 
> please advice. thanks...

Most modern micro kernel based operating systems are message passing based.

VxWorks and Linux are not micro kernel based ...Minix 3.0 and QNX are.

--Armin

> or you can consider it the senders role to make a copy to send if it
> needs to maintain an un modified version of the message.

In the case of DPS, it is indeed the sender which does the copying,
the copying code being part of the recipient PSCT, though. IOW, the
sender does a system call which will transfer the message, and the
system takes care of calling the respective code in the recipients
program module.
 Typically, I have two files I link for such purposes, std and qstd,
the latter does queue the incoming signals while the former does
not (it will time out if the recipient task has not processed the
last incoming message for some time; well, so will the qstd as
well, but after the queue has been filled up :-).
 But like I said earlier, this is only one way I use for intertask
communication in DPS. I also do a lot of "object specific" exchanges,
which are mostly using commonly accessed memory pieces
with atomic locks.

Dimiter

------------------------------------------------------
Dimiter Popoff               Transgalactic Instruments

http://www.tgi-sci.com
------------------------------------------------------

jacko wrote:
> Didi wrote:
> > > ....are kept in a Nucleus which use
> > > regular calling mechanisms and copyless message passing.
> >
> > Actually you do need both "copyless" and "copied" message passing.
> > The former obviously saves overhead, the latter comes handy when
> > the mesage is passed by a task which will get killed possibly prior
> > to its message has been processed by the recipient and (the message)
> > resides in memory which will be deallocated when the task is killed.
> >
> > Dimiter
> >
>
> or you can consider it the senders role to make a copy to send if it
> needs to maintain an un modified version of the message.

Didi wrote:
> > ....are kept in a Nucleus which use
> > regular calling mechanisms and copyless message passing.
>
> Actually you do need both "copyless" and "copied" message passing.
> The former obviously saves overhead, the latter comes handy when
> the mesage is passed by a task which will get killed possibly prior
> to its message has been processed by the recipient and (the message)
> resides in memory which will be deallocated when the task is killed.
>
> Dimiter
>

or you can consider it the senders role to make a copy to send if it
needs to maintain an un modified version of the message.

>> ... The software (well, the whole product, actually) was very much like a 
>> stinking pile of dog doo wrapped in a tasty candy shell ...

>SPOCWIACS

>(Stinking Pile Of Crap Wrapped In A Candy Shell)

>(I was considering using "Steaming" for the first
>word, but the Candy Shell probably wouldn't hold up)

>There must be some good ones out there with a similar
>theme, seeing how universally applicable the concept is:
>e.g. political platforms, company benefit packages, Microsoft
>operating systems, etc...


"you can shellac it and paint it colors, but if you poke at it, you'll 
find that it's still a turd."

(in fererence to a popular GUI OS)


-- 
	mac the na�f

> ....are kept in a Nucleus which use
> regular calling mechanisms and copyless message passing.

Actually you do need both "copyless" and "copied" message passing.
The former obviously saves overhead, the latter comes handy when
the mesage is passed by a task which will get killed possibly prior
to its message has been processed by the recipient and (the message)
resides in memory which will be deallocated when the task is killed.

Dimiter

------------------------------------------------------
Dimiter Popoff               Transgalactic Instruments

http://www.tgi-sci.com
------------------------------------------------------


dmctek.googlepages.com wrote:
> Most modern RTOS, especially those claiming to be Microkernel based
> will use some form of Message passing in the OS Kernel somewhere
> especially if they are the more sophisticated type offering services
> such as networking and filesystems. Whilst message passing provides
> good benefits such as maximum configurability and strong preemptivity
> the overhead in message passing is always noticeable so most of the
> core services in the microkernels are kept in a Nucleus which use
> regular calling mechanisms and copyless message passing. I have worked
> on full unix microkernelised O/S were after serverisation a routine
> syscall was 300% slower - in general I think that ever faster
> microprocessor clocking is supposed to soak this kind of impact up
> allowing for ever sophisticated software design?
>
> I have been working on a set of slides about embedded systems which
> includes this type of discussion and covers the various linux based
> approaches I would expect some small fee for them 40$ - if I get enough
> of a response I could finish them and send them out to requesters.
>
> Cheers.
> dmctek.googlepages.com
>
>
>
>
>
> John wrote:
>
> > Are most modern RTOS message-based operating systems? For example,
> > VxWorks, or embedded linux OS? I try to understand how tasks
> > communicate with each other? My understanding is that tasks can
> > communicate via messages, or mails? Any other approaches?
> > 
> > please advice. thanks...

Most modern RTOS, especially those claiming to be Microkernel based
will use some form of Message passing in the OS Kernel somewhere
especially if they are the more sophisticated type offering services
such as networking and filesystems. Whilst message passing provides
good benefits such as maximum configurability and strong preemptivity
the overhead in message passing is always noticeable so most of the
core services in the microkernels are kept in a Nucleus which use
regular calling mechanisms and copyless message passing. I have worked
on full unix microkernelised O/S were after serverisation a routine
syscall was 300% slower - in general I think that ever faster
microprocessor clocking is supposed to soak this kind of impact up
allowing for ever sophisticated software design?

I have been working on a set of slides about embedded systems which
includes this type of discussion and covers the various linux based
approaches I would expect some small fee for them 40$ - if I get enough
of a response I could finish them and send them out to requesters.

Cheers.
dmctek.googlepages.com





John wrote:

> Are most modern RTOS message-based operating systems? For example,
> VxWorks, or embedded linux OS? I try to understand how tasks
> communicate with each other? My understanding is that tasks can
> communicate via messages, or mails? Any other approaches?
> 
> please advice. thanks...

Most modern RTOS, especially those claiming to be Microkernel based
will use some form of Message passing in the OS Kernel somewhere
especially if they are the more sophisticated type offering services
such as networking and filesystems. Whilst message passing provides
good benefits such as maximum configurability and strong preemptivity
the overhead in message passing is always noticeable so most of the
core services in the microkernels are kept in a Nucleus which use
regular calling mechanisms and copyless message passing. I have worked
on full unix microkernelised O/S were after serverisation a routine
syscall was 300% slower - in general I think that ever faster
microprocessor clocking is supposed to soak this kind of impact up
allowing for ever sophisticated software design?

I have been working on a set of slides about embedded systems which
includes this type of discussion and covers the various linux based
approaches I would expect some small fee for them 40$ - if I get enough
of a response I could finish them and send them out to requesters.

Cheers.
dmctek.googlepages.com





John wrote:

> Are most modern RTOS message-based operating systems? For example,
> VxWorks, or embedded linux OS? I try to understand how tasks
> communicate with each other? My understanding is that tasks can
> communicate via messages, or mails? Any other approaches?
> 
> please advice. thanks...

Most modern RTOS, especially those claiming to be Microkernel based
will use some form of Message passing in the OS Kernel somewhere
especially if they are the more sophisticated type offering services
such as networking and filesystems. Whilst message passing provides
good benefits such as maximum configurability and strong preemptivity
the overhead in message passing is always noticeable so most of the
core services in the microkernels are kept in a Nucleus which use
regular calling mechanisms and copyless message passing. I have worked
on full unix microkernelised O/S were after serverisation a routine
syscall was 300% slower - in general I think that ever faster
microprocessor clocking is supposed to soak this kind of impact up
allowing for ever sophisticated software design?

I have been working on a set of slides about embedded systems which
includes this type of discussion and covers the various linux based
approaches I would expect some small fee for them 40$ - if I get enough
of a response I could finish them and send them out to requesters.

Cheers.
dmctek.googlepages.com





John wrote:

> Are most modern RTOS message-based operating systems? For example,
> VxWorks, or embedded linux OS? I try to understand how tasks
> communicate with each other? My understanding is that tasks can
> communicate via messages, or mails? Any other approaches?
> 
> please advice. thanks...

"Tim Wescott" <tim@seemywebsite.com> wrote in message 
news:TZSdndF5SfpHksHYnZ2dnUVZ_uGdnZ2d@web-ster.com...
> ... The software (well, the whole product, actually) was very much like a 
> stinking pile of dog doo wrapped in a tasty candy shell ...

I liked this one...

So much I tried to paraphrase it into a plausible (pronounceable) acronym
for future usage, such as:

SPOCWIACS

(Stinking Pile Of Crap Wrapped In A Candy Shell)


(I was considering using "Steaming" for the first
word, but the Candy Shell probably wouldn't hold up)


There must be some good ones out there with a similar
theme, seeing how universally applicable the concept is:
e.g. political platforms, company benefit packages, Microsoft
operating systems, etc...

On Thu, 16 Nov 2006 11:32:56 +0530, "Harsha" <sriharshab@gmail.com>
wrote:

>This will be helpful to you.
>OSE              ---------------         Signals with buffers, shared memory
shared memory ?? Ah, yes OSE provides semaphores if you mean this by
shared memory.

Sciopta              ---------------         Signals with buffers

Note: OSE and Sciopta use direct message passing, no intermediate
mailbox needed.


-- 
42Bastian
Do not email to bastian42@yahoo.com, it's a spam-only account :-)
Use <same-name>@monlynx.de instead !