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From: philf@xymox.metaphor.com (Phil Fernandez)
Newsgroups: comp.os.os2,comp.realtime
Subject: Re: OS/2, real-time, question
Keywords: OS/2, real-time, question
Message-ID: <864@metaphor.Metaphor.COM>
Date: 30 Oct 89 02:23:46 GMT
References: <34689@beta.lanl.gov> <1028@ncratl2.Atlanta.NCR.COM>
Sender: news@metaphor.Metaphor.COM
Reply-To: philf@xymox.metaphor.com (Phil Fernandez)
Distribution: usa
Organization: Metaphor Computer Systems, Mountain View, CA
Lines: 48

In article <1028@ncratl2.Atlanta.NCR.COM> r.nathan@Atlanta.NCR.COM writes:
>In article <34689@beta.lanl.gov> tss@beta.lanl.gov (Timothy Sullivan) writes:
>>I realize this is an absurdably premature question, but is anyone doing
>>anything about implementing a real-time OS/2? Given its single-user,
>>multitasking orientation it would be a great platform for process control,
>>data acquisition, and the like.
>...
>And yes, OS/2 does make a good platform for real-time stuff.  The 
>implementation of threads, queues and ram-semaphores, exitlists, and so
>forth provides all the mechanisms one really needs.  I can't say how well
>it would work for real-time controls at the milli-second precision range,
>but in the relatively slow environment I designed for, it was (dare I say
>it?) great.

At Metaphor, we have recently released an SNA <-> Ethernet/Token Ring
LAN gateway based on OS/2 running on a PS/2.  On the SNA side, we
support LU6.2 communications on SDLC or TR lines; on the LAN side we
support XNS over Ethernet or TR.  As a communications gateway serving
perhaps 15-20+ workstations on the LAN, this qualifies under some
cdefinitions as a real-time application.

The product definitely works, but this implementation effort taught us
some things about OS/2 in this kind of application:

First, there's little information about system performance, either in
documentation or through developers' tools.  So, it's difficult to
model the performance of system services, such as thread creation, IPC
or inter-tread communication, etc.  Also, it's difficult to understand
"second order" effects, e.g., what's the effect on performance of
creating one more thread.

Second, some key services are slow -- thread creation among them.  So,
in applications that depend on "cheap" threads, OS/2 is perhaps not a
great idea.

These comments apply to OS/2 EE 1.1...soon I'll know if 1.2 offers any
real improvements.

phil

(This opinions are mine only, and do not necessarily reflect the
opinions of Metaphor Computer Systems.)
+-----------------------------+----------------------------------------------+
| Phil Fernandez              |             philf@metaphor.com               |
|                             |     ...!{apple|decwrl}!metaphor!philf        |
| Metaphor Computer Systems   |"Does the body rule the mind, or does the mind|
| Mountain View, CA           | rule the body?  I dunno..." - Morrissey      |
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