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NNTP-Posting-Date: Mon, 31 Jul 2017 19:54:08 -0500
From: Dennis Lee Bieber <wlfraed@ix.netcom.com>
Newsgroups: comp.lang.ada
Subject: Re: What is the current language profile for concurrent, multi-core,
 safety-critical, hard real-time systems?
Date: Mon, 31 Jul 2017 20:54:08 -0400
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Xref: news.eternal-september.org comp.lang.ada:47534
Date: 2017-07-31T20:54:08-04:00
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On Tue, 1 Aug 2017 00:25:18 -0000 (UTC), Adam Jensen <hanzer@riseup.net>
declaimed the following:

>
>What is the current Ada language profile for concurrent, multi-core, 
>safety-critical, hard real-time systems? 

	As soon as you say "multi-core" you enter the realm of experimental
science. For example -- in the four years I spent at GE Aviation,
multi-core processors used in flight management software would be run with
all but one core shutdown.

	Reason: there has not been enough experience/study of how multiple
cores/cache/etc. affect hard real-time latency (how can you evaluate WCET
for a process on core-A when you don't have control of what happens on
core-B, which could cause cache line flushing, etc. affecting the timing of
core-A)

	What multi-core processors I saw being used in development were for
non-safety critical functions -- data logging type operations, wherein loss
of the logging processor wouldn't affect the flight management system; only
reducing the post-flight analysis capabilities should there be anomalous
flight operations.
-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
    wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/