Re: ONYX2 Serial Port Question

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Angus Dorbie (dorbie++at++sgi.com)
Wed, 29 Sep 1999 15:03:40 -0700

Well if you need to add more serial ports I suppose that this might be
an option, but there are four built in already and you don't need any
expensive libraries or components to use them. Just simple serial i/o
code. Reading serial on a PC and sending it over the network adds
latency (almost zero is meaningless) and packet reliability issues. The
PC also adds cost if you need less than four ports and a fair amount of
non recurring engineering costs for those who count that sort of thing.

Cheers,Angus.

Ryan Thomas Tecco wrote:
>
> Hello, my name is Ryan, I designed/wrote the underlaying CORBA
> communication layer for Ross's sensor data application.
>
> CORBA's network latency between machines on a decently-congested subnet is
> almost zero. We are taking real-time data here, we wouldn't use it if it
> was slow. The CORBA implementation often shields you from the underlying
> networking stuff, so you often get a very well written and thought out
> implementation.
>
> I'd suggest omniORB2, from AT&T. It's free and, the average RMI is several
> milliseconds shorter then Visibroker and several other professional (read:
> *ridicuously* expensive, a *trial* license for Visibroker costs in the
> thousands, a full copy, in the tens of thousands) check out:
>
> http://www.uk.research.att.com/omniORB/omniORBPerformance.html
>
> For an in-depth look. It's a real simple, elegant system for adding on
> serial ports, considering that port boards for PC desktops are much
> cheaper than an Onyx2.
>
> Word,
> rt
>
> On Wed, 29 Sep 1999, Angus Dorbie wrote:
>
> > But if the ports are there anyway then you don't want to force extra
> > network comms and latency etc on your million dollar box. It doesn't
> > seem like a better solution, just an alternative and possibly worse
> > method of interfacing to the SGI.
> >
> > Cheers,ANgus.
> >
> > ross::barna wrote:
> > >
> > > we have an free (with source) system that allows you to use the serial
> > > ports on a linux box (cheap PC) with Performer (or other libs) on an IRIX
> > > box.... it also allows for multiple application access to the serial port.
> > >
> > > saving you the grief of using a million dollar box for serial comm!
> > >
> > > if you are interested, email me.
> > >
> > > -ross
> > >
> > > _____________________________
> > > ross::barna
> > > joga.ummu.umich.edu
> > >
> > > On Wed, 29 Sep 1999, Paul S. Cutt wrote:
> > >
> > > >
> > > > Dear Murray,
> > > >
> > > > We provide a serial port toolkit XvsLink for driving serial devices under
> > > > Performer which takes over the work of interfacing with serial devices.
> > > >
> > > > I know this does not directly answer your question but just wanted
> > > > you to know there is software out there to handle serial devices for you.
> > > > Saving you debugging time.
> > > >
> > > > Thanks,
> > > >
> > > > paul
> > > > www.xtensory.com
> > > > Xtensory Inc
> > > >
> > > > On Wed, 29 Sep 1999, Gamble, Murray - Kan AV HFE wrote:
> > > >
> > > > >
> > > > > Hi All,
> > > > >
> > > > > I hate to send serial port questions to this group, but the scope of
> > > > > knowledge represented by the subscribers is just too darn attractive to
> > > > > ignore.
> > > > >
> > > > > Anyways, here's my problem. We have a nice new shiny ONYX2 box in our
> > > > > lab :-) and are trying to drive several serial devices from the four
> > > > > serial ports. We are using well known serial devices that have a hsitory
> > > > > of behaving well but are experiencing an inconsistency between the four
> > > > > ports. The devices work properly when attached to /dev/ttyd1 and
> > > > > /dev/ttyd2 but display garbage when connected to /dev/ttyd3 or
> > > > > /dev/ttyd4. I have checked the "/etc/inittab" file and all four ports
> > > > > are configured identically (well, actually port 1 is configured as a
> > > > > console, but with respawn turned "off" - and it works, so I won't
> > > > > complain). In addition, we have tried connecting the same devices to an
> > > > > Octane (which, upon examination of the "/etc/inittab" file has the same
> > > > > settings as the ONYX2) and they don't work there either! I get the same
> > > > > gobbledy-gook on ports 1 & 2 on the Octane as I do on ports 3 &4 on the
> > > > > ONYX2.
> > > > >
> > > > > Ultimately, we would like to drive these devices from an Octane, but have
> > > > > been using the ONYX2, since ports 1 & 2 seem to give us the only workable
> > > > > option thus far.
> > > > >
> > > > > Any and all help is greatly appreciated,
> > > > >
> > > > > Thanks,
> > > > >
> > > > > Murray.
> > > > >
> > > > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> > > > > Murray G. Gamble, B.Eng
> > > > > Human Factors Engineering - Aerospace
> > > > > Marconi Canada
> > > > > Kanata, Ontario, CANADA
> > > > > -----------------------------------------------------------------------
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> > > > >
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> > > >
> > >
> > > -----------------------------------------------------------------------
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> >
> > --
> > "One of the best-known folk theorems of software engineering is that
> > 60% to 75% of conventional software projects are either never
> > completed or rejected by their intended users. If that range is
> > anywhere near true (and I've never met a manager of any experience
> > who disputes it) then more projects than not are being aimed at goals
> > which are either (a) not realistically attainable, or (b) just plain
> > wrong."
> > Eric S. Raymond - The Cathedral and The Bazaar
> >
> > For advanced 3D graphics Performer + OpenGL based examples and tutors:
> > http://www.dorbie.com/
> >
>
> ---------------
> ryan.tecco
> 734.476.6646
> the university of michigan
> "i change colors."
>
> -----------------------------------------------------------------------
> List Archives, FAQ, FTP: http://www.sgi.com/software/performer/
> Submissions: info-performer++at++sgi.com
> Admin. requests: info-performer-request++at++sgi.com

-- 
"One of the best-known folk theorems of software engineering is that
60% to 75% of conventional software projects are either never
completed or rejected by their intended users. If that range is
anywhere near true (and I've never met a manager of any experience
who disputes it) then more projects than not are being aimed at goals
which are either (a) not realistically attainable, or (b) just plain
wrong."
                 Eric S. Raymond - The Cathedral and The Bazaar


For advanced 3D graphics Performer + OpenGL based examples and tutors:
http://www.dorbie.com/

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