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Groups > comp.arch.embedded > #12833
| From | Don Y <this@isnotme.com> |
|---|---|
| Newsgroups | comp.arch.embedded, comp.realtime |
| Subject | Re: Resource revocation |
| Date | 2013-07-29 13:16 -0700 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <kt6iih$ec8$1@speranza.aioe.org> (permalink) |
| References | (11 earlier) <_riJt.598075$%p1.483412@en-nntp-02.dc1.easynews.com> <kt4gtl$q0g$1@speranza.aioe.org> <HWlJt.4$nK2.2@en-nntp-11.dc1.easynews.com> <kt559c$6s7$1@speranza.aioe.org> <1OzJt.15365$Zi1.8525@fx15.am4> |
Cross-posted to 2 groups.
Hi Tom,
On 7/29/2013 12:56 PM, Tom Gardner wrote:
> On 29/07/13 08:23, Don Y wrote:
>> Yes. But only if one (or more) of the HRT tasks missed its deadline.
>> Calling a SYSTEM "hard" means very little. It just says, "I am
>> brittle (and probably over-specified)"
>
> Too simplistic.
>
> I once implemented a lung ventilator. If the airway pressure
> was too high and I missed a 50ms deadline for reducing it,
> does that mean the the system was brittle and over specified?
You've misread my comment. Since you MISSED that HARD deadline
(in a HARD *system*, not just a hard *task*), you obviously
didn't specify *enough* resources in your system design to
guarantee *meeting* the deadline. (even if those resources
would seldom have been needed/used)
[Alternatively, the system you have defined does not meet the
stated qualification of "HARD RT *system* -- it just happened to
be *a* RT system that had a hard deadline that it happened
to have missed. Presumably, the system specification gave
you some leeway in how many of these deadlines you *could*
miss and still be considered "functional". Perhaps "miss no
more than one out of every ten and never two consecutively".
Such a specification would be an acknowledgement that trying
to meet every such deadline would be too costly to implement;
i.e., contain far more resources than necessary probabilistically]
Cf:
"A system having only actions with hard deadlines, and a
sequencing goal of always meeting all those hard deadlines (i.e.,
deterministic maximum sequencing optimality), is a hard real-time
system"
and:
"A hard real-time system is one whose sequencing timeliness
factors (there also may be non-timeliness factors) are:
* optimality is the binary case that meeting all hard deadlines
is optimal and otherwise is suboptimal (in some system-,
application-, or situation-specific way)
* predictability of optimality is deterministic."
I.e., if your system specification ALLOWED you to miss that one
deadline, then it wasn't a hard real-time system!
That's why it's important to have a taxonomy and well-defined
means of categorizing problems and implementations. So its
more than just :this *seems* like it is more important than
that" (OK, then that should be reflected by the system
design and metrics that let others come to that same conclusion.)
Instead, we get folks conflating speed/frequency, safety, damage,
monetary cost, etc. -- all things that have emotional appeal
but no real scientific/mathematical basis (that could be fed into
a scheduling algorithm, etc.)
> (I accept that the human part of the system would have been
> brittle under those circumstances, but as I haven't seen a
> spec for a human I can't comment on whether humans are
> over-specified :)
>
> Ditto missing a deadline for having a breath!
>
> Of course, "deadline" is peculiarly apt terminology in these
> circumstances :)
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Resource revocation Don Y <this@isnotme.com> - 2013-07-25 12:23 -0700
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-25 12:51 -0700
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-25 15:00 -0700
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-25 19:38 -0700
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-25 22:12 -0700
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-25 23:37 -0700
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-26 01:13 -0700
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-26 02:48 -0700
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-26 04:19 -0700
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-26 09:46 -0700
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-26 10:21 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-26 19:30 +0100
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-26 11:56 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-26 20:08 +0100
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-26 13:11 -0700
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-26 12:31 -0700
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-27 11:08 -0700
Re: Resource revocation Rob Gaddi <rgaddi@technologyhighland.invalid> - 2013-07-29 09:16 -0700
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-29 10:22 -0700
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-29 11:22 -0700
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-27 08:56 -0700
Re: Resource revocation Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2013-07-26 19:25 +0200
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-26 10:51 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-26 19:21 +0100
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-26 11:50 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-26 19:42 +0100
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-26 12:43 -0700
Does the Buddha have a real time nature? ;) (was Resource revocation) Roberto Waltman <usenet@rwaltman.com> - 2013-07-26 17:06 -0400
Re: Does the Buddha have a real time nature? ;) (was Resource revocation) Don Y <this@isnotme.com> - 2013-07-26 17:12 -0700
Re: Does the Buddha have a real time nature? ;) (was Resource revocation) Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-27 09:44 +0100
Re: Does the Buddha have a real time nature? ;) (was Resource revocation) Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-27 09:45 +0100
Re: Does the Buddha have a real time nature? ;) (was Resource revocation) Don Y <this@isnotme.com> - 2013-07-27 12:28 -0700
Re: Does the Buddha have a real time nature? ;) (was Resource revocation) Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2013-07-27 14:11 +0200
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-26 12:40 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-26 21:29 +0100
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-26 13:52 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-26 22:55 +0100
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-26 17:22 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-27 10:02 +0100
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-27 09:29 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-27 18:20 +0100
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-27 12:48 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-27 22:57 +0100
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-27 16:18 -0700
Re: Resource revocation Roberto Waltman <usenet@rwaltman.com> - 2013-07-31 16:33 -0400
Re: Resource revocation upsidedown@downunder.com - 2013-07-27 22:53 +0300
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-27 22:42 +0100
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-27 16:41 -0700
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-27 16:49 -0700
Re: Resource revocation upsidedown@downunder.com - 2013-07-28 08:39 +0300
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-27 23:11 -0700
Re: Resource revocation Roberto Waltman <usenet@rwaltman.com> - 2013-07-31 16:15 -0400
Re: Resource revocation upsidedown@downunder.com - 2013-08-01 00:13 +0300
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-27 15:16 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-27 23:05 +0100
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-27 15:37 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-27 23:38 +0100
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-27 16:08 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-28 01:16 +0100
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-27 18:43 -0700
Re: Resource revocation upsidedown@downunder.com - 2013-07-28 09:01 +0300
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-27 15:21 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-27 23:07 +0100
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-26 12:00 -0700
Re: Resource revocation stephenXXX@mpeforth.com (Stephen Pelc) - 2013-07-27 16:49 +0000
Re: Resource revocation Richard Damon <Richard@Damon-Family.org> - 2013-07-28 18:31 -0400
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-28 15:51 -0700
Re: Resource revocation Richard Damon <Richard@Damon-Family.org> - 2013-07-28 20:12 -0400
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-28 18:35 -0700
Re: Resource revocation Richard Damon <Richard@Damon-Family.org> - 2013-07-29 00:10 -0400
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-29 00:23 -0700
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-29 01:05 -0700
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-29 12:07 -0700
Re: Resource revocation upsidedown@downunder.com - 2013-07-30 01:11 +0300
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-29 15:20 -0700
Re: Resource revocation Rob Gaddi <rgaddi@technologyhighland.invalid> - 2013-07-29 15:42 -0700
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-29 16:41 -0700
Re: Resource revocation upsidedown@downunder.com - 2013-07-30 08:51 +0300
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-30 09:09 +0100
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-30 01:30 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-30 10:04 +0100
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-30 02:55 -0700
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-30 07:12 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-30 16:59 +0100
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-30 13:17 -0700
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-30 10:12 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-30 18:48 +0100
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-30 20:18 -0700
Re: Resource revocation upsidedown@downunder.com - 2013-07-31 09:27 +0300
Re: Resource revocation [long] Don Y <this@isnotme.com> - 2013-07-31 00:47 -0700
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-30 02:50 -0700
Re: Resource revocation upsidedown@downunder.com - 2013-07-30 13:22 +0300
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-30 07:24 -0700
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-30 01:17 -0700
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-29 19:28 -0700
Re: Resource revocation upsidedown@downunder.com - 2013-07-29 11:40 +0300
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-29 11:44 -0700
Re: Resource revocation Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-07-29 20:56 +0100
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-29 13:16 -0700
Re: Resource revocation Richard Damon <Richard@Damon-Family.org> - 2013-07-30 00:08 -0400
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-30 23:41 -0700
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-31 00:58 -0700
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-31 10:18 -0700
Re: Resource revocation George Neuner <gneuner2@comcast.net> - 2013-08-02 06:19 -0400
Re: Resource revocation Richard Damon <Richard@Damon-Family.org> - 2013-08-03 02:26 -0400
Re: Resource revocation Paul Rubin <no.email@nospam.invalid> - 2013-07-28 19:31 -0700
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-29 00:44 -0700
Re: Resource revocation Richard Damon <Richard@Damon-Family.org> - 2013-07-25 22:42 -0400
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-25 22:12 -0700
Re: Resource revocation "Boudewijn Dijkstra" <sp4mtr4p.boudewijn@indes.com> - 2013-07-31 13:41 +0200
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-31 07:51 -0700
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-31 08:07 -0700
Re: Resource revocation Anders.Montonen@kapsi.spam.stop.fi.invalid - 2013-07-31 15:55 +0000
Re: Resource revocation Don Y <this@isnotme.com> - 2013-07-31 10:18 -0700
Re: Resource revocation "Boudewijn Dijkstra" <sp4mtr4p.boudewijn@indes.com> - 2013-08-01 14:42 +0200
Re: Resource revocation Don Y <this@isnotme.com> - 2013-08-01 14:34 -0700
Re: Resource revocation upsidedown@downunder.com - 2013-08-02 09:08 +0300
Re: Resource revocation Don Y <this@isnotme.com> - 2013-08-02 07:26 -0700
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