When communciating with in a system what is that called ?

Do you have a question? Post it now! No Registration Necessary

Translate This Thread From English to

Threaded View
Hi

If i have a CPU and there is the Term IPC Interprocess communication
to communicate with in the CPU e.g shared memory , sockets, pipes
e.t.c


How do i call that when i have a system . e.g 5 cpu and the CPU will
communicate with each other is there a term simular to IPC ?

Re: When communciating with in a system what is that called ?
There is the term "multiprocessor system". These can be "tightly coupled" or
"loosely coupled". A book on Computer Architecture should discuss those terms.

Re: When communciating with in a system what is that called ?

Quoted text here. Click to load it

Why even use a different one rather than sticking with the term you
already have?  

Just because the various processes now run on different CPUs doesn't
make their communication no longer be inter-process-communcation.  IPC
implementation will obviously be more complicated, due to the presence
of more than one processor actually working in parallel, but's it's
still IPC.  That would change only if you had an OS that supported
several CPUs running several threads of the same processes.

[And since none of this would usually be particularly relevant to
embedded computing, I suggest you ask further questions elsewhere.]
--
Hans-Bernhard Broeker ( snipped-for-privacy@physik.rwth-aachen.de)
Even if all the snow were burnt, ashes would remain.

Re: When communciating with in a system what is that called ?
I think you should go else where to ask what is embedded computing!
I presume you mean embedded systems because to my knowledge shared
memory , sockets, pipes CPU and how a system communicates with each
other belongs to Embedded Systems.

Re: When communciating with in a system what is that called ?
Quoted text here. Click to load it

I think you should go else where to ask what is embedded computing!
I presume you mean embedded systems because to my knowledge shared
memory , sockets, pipes CPU and how a system communicates with each
other belongs to Embedded Systems.

Re: When communciating with in a system what is that called ?
Quoted text here. Click to load it

I'm always looking for good names that provide concise
distinctions, so this question rings a chord.

Along the lines of your question, I like to distinguish
between IPC (Inter Process Communications), a broadly applied
term, and ITC (Inter Thread Communications). The difference
being that threads share a single address space whereas
processes do not (ignoring shared memory segments for the moment).

In my mind, your question needs needs more background.
CPU's can be connected and communicate in many different
ways, none of which you specified. In the most general
sense, I think you would call it "data communications".
This, however, usually conjours up pictures of WANs and
LANs.

Symetrical Multi Processing (SMP) systems have more than
one processor sharing the same address space. In this case
the processors communicate through the RAM that they share
over a common bus. Also typical of SMP configurations is
that the CPUs run a single copy of the operating system,
and the operating system schedules threads among the CPU's.
These configurations are generally availabe in high end
desktop computers.

There are also other configurations where CPUs share RAM
but execute independently, the logical address spaces
of the CPUs are not necessarily the same, and indeed the
CPUs themselves may be of different types. Such configurations
are common in VME and similalr bus based systems. These
configurations are common in big expensive fast real-time
systems.

More common of this news group are systems that communicate
over some sort of serial data link e.g. UART/RS232, I2C,
SPI and HDLC.

Blah blah blah ... sorry for the rambling
"non-answer" :-)


--
Michael N. Moran           (h) 770 516 7918
5009 Old Field Ct.         (c) 678 521 5460
We've slightly trimmed the long signature. Click to see the full one.
Re: When communciating with in a system what is that called ?
Quoted text here. Click to load it

Hi Michael

What would you call the following scenario?

I have a PC104, PowerPC, Network Processor from Intel, which runs a
Real Time Operating system. And embedded linux running on a 8240, i
communicate over LAN and rs232 between the devices.

I want to be able to communicate within the system.

What would you call the communication term between the device?

Multiprocessor system?
System communicating  ?
Embedded Communication ?
IPC over a system?

Re: When communciating with in a system what is that called ?
Quoted text here. Click to load it

A big mess ;-)

Quoted text here. Click to load it

Quite a bit of diversity. This is a single embedded system?

Quoted text here. Click to load it

I don't quite know what to make of this statement.
What do you mean by you "want to be able to communicate
within the system?"

Quoted text here. Click to load it
Sounds like a multiprocessor system.
Quoted text here. Click to load it
Hmmm.
Hmmm.
I don't know what this means.

The only thing that I can think of that might
even come close is "Distributed Computing", but
that is not a term I usually associate with
embedded systems, and its not really a term
for communications.

Given that the mediums are LAN and RS232, and
not knowing anything more about the application,
I'd just call it data communications.

--
Michael N. Moran           (h) 770 516 7918
5009 Old Field Ct.         (c) 678 521 5460
We've slightly trimmed the long signature. Click to see the full one.
Re: When communciating with in a system what is that called ?
Quoted text here. Click to load it

The problem there is normally in a embedded system you have 2 types of
messages trransfers or message interface

1. Data
2. Commands

where data can drop messages and commands can not drop any messages.

Re: When communciating with in a system what is that called ?
Quoted text here. Click to load it

I have never heard this distinction made along
the lines of data and commands. The term "data
communications" refers to the transfer of information
independent of whether that data is command or
data.

I *have* heard of the following types of
data communication which have to do with
the delivery requirements/semantics.

At-Most-Once
At-Least-Once
Exactly-Once

With at-most-once transfers, a single "packet"
of data is sent toward the receiver, and may
or may not be actually received depending upon
the network between the sender and receiver.

At-least-once transfers operate by sending
the same packet several times in the hope that
at least one copy of the packet is received.

Exactly-once tranfers follow a protocol of
data transfer, acknowledglements and timers
that, short of a major connectivity problem,
ensure that exactly one copy of the packet
is delivered to the receiving application.


--
Michael N. Moran           (h) 770 516 7918
5009 Old Field Ct.         (c) 678 521 5460
We've slightly trimmed the long signature. Click to see the full one.
Re: When communciating with in a system what is that called ?
Quoted text here. Click to load it

I worked on a similar system.  Very interesting project if you
ever get a chance to do it.   We have Mips, PPC, Linux with x86
SMP, Other RTOS with X86 etc.  This kind of system is very
typical for big telecom equipements.   Fews CPU cards even had
2 GB of RAM in it.

Very interesting to debug.  All kind of messages flying everywhere.
Application might be blocked on something and claim to miss the messages
from somethere else, etc, etc.  Have to generate a few custome
tools to debug all kind of distributed messaging issues.  It is amazed
that the system works at all.  I thought we would be crushed
to dead by the complexity of the system.  


--
SLink create hyperlinks for all functions, macros, variables from
thousands of files.  Browse hyperlinked source code for .NET CLI,
We've slightly trimmed the long signature. Click to see the full one.
Re: When communciating with in a system what is that called ?
Quoted text here. Click to load it

Interesting, telecom happens to be my background, although
I've never worked on a system with *that* many different
processors.

Back to the OP's question, how about:

"Distributed Computing in a Heterogeneous Computing Environment"

1/2 :-)

While I laugh at this description, it truly is a discription
of some of the problems that must be solved in these kinds
of systems. The trick is to get management to understand
the impact on the schedule.

Quoted text here. Click to load it

Indeed. Complexity managment is the name-of-the-game
in telecom. The trick is to not only meet the initial
"first release" requirements, but to design a framework
that will allow the "next generation" requirements
to be met without starting from scratch. Solid system
architecture is the key to long term success.


--
Michael N. Moran           (h) 770 516 7918
5009 Old Field Ct.         (c) 678 521 5460
We've slightly trimmed the long signature. Click to see the full one.
Re: When communciating with in a system what is that called ?
Quoted text here. Click to load it


I have work for embeded systems for the last 7 years and it is very
common to combine different processors for example C16x, PowerPC,
Intel PC , TMS320C25 in one system. The first problem you have is the
byte order, but that is not the topic here

That was one Telecom project that i worked on which combined the
Processors above.

Site Timeline