From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 27182 invoked by alias); 18 Jun 2006 23:46:32 -0000 Received: (qmail 27174 invoked by uid 22791); 18 Jun 2006 23:46:31 -0000 X-Spam-Check-By: sourceware.org Received: from smtp1.iitb.ac.in (HELO smtp1.iitb.ac.in) (59.163.25.49) by sourceware.org (qpsmtpd/0.31) with SMTP; Sun, 18 Jun 2006 23:46:28 +0000 Received: (qmail 3303 invoked from network); 19 Jun 2006 05:16:01 +0530 Received: from unknown (HELO ldns1.iitb.ac.in) (10.200.12.1) by smtp1.iitb.ac.in with SMTP; 19 Jun 2006 05:16:01 +0530 Received: (qmail 31332 invoked by uid 509); 18 Jun 2006 23:46:01 -0000 Received: from 10.105.1.1 by ldns1 (envelope-from , uid 501) with qmail-scanner-1.25 (clamdscan: 0.88.2/1549. spamassassin: 3.1.0. Clear:RC:1(10.105.1.1):. Processed in 0.024483 secs); 18 Jun 2006 23:46:01 -0000 Received: from unknown (HELO cse.iitb.ac.in) (10.105.1.1) by ldns1.iitb.ac.in with SMTP; 18 Jun 2006 23:46:01 -0000 Received: (qmail 7814 invoked by uid 11940); 18 Jun 2006 23:51:32 -0000 Received: from 10.105.1.11 by jeeves.cse.iitb.ac.in (envelope-from , uid 11926) with qmail-scanner-1.25 (clamdscan: 0.87/1549. spamassassin: 3.1.0. Clear:RC:1(10.105.1.11):. Processed in 0.02892 secs); 18 Jun 2006 23:51:32 -0000 Received: from mars.cse.iitb.ac.in ([10.105.1.11]) (envelope-sender ) by cse.iitb.ac.in (qmail-ldap-1.03) with SMTP for ; 18 Jun 2006 23:51:32 -0000 Date: Sun, 18 Jun 2006 23:46:00 -0000 From: R Vamshi Krishna To: John Carter cc: ecos-discuss@sourceware.org In-Reply-To: Message-ID: References: <20060530075335.GG2876@lunn.ch><69dd805e0605300109k5dcf7986of596c0b5f796c6b 4@mail.gmail.com><20060530081637.GH2876@lunn.ch><20060530111112.GK2876@lunn.ch><001501c6874a$10fbb9a0$070fe644@EngAt PlayWS><003401c6885d $23027ee0$070fe644@EngAtPlayWS> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-IsSubscribed: yes Mailing-List: contact ecos-discuss-help@ecos.sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: ecos-discuss-owner@ecos.sourceware.org Subject: Re: [ECOS] Hard-Realtime behaviour X-SW-Source: 2006-06/txt/msg00159.txt.bz2 Thank you for the reply. But the fact remains that we would like to have a "Hard" real-time OS irrespective of the processor/speed and ram/rom. Any help regarding hardening of eCos would be welcome. On Mon, 19 Jun 2006, John Carter wrote: > On Mon, 19 Jun 2006, R Vamshi Krishna wrote: > >> Now this hard real-time OS would be for use in Safety-Critical Systems. We >> would port the kernel to MISRA-C later stage but currently we are stuck-up >> at "hardening" of eCos. > > Since currently most of the kernel seems to be C++, that wouldn't be > "port", that would be "rewrite". ie. If MISRA-C for the kernel is a > fixed requirement, you have lost right there. > My mistake. I indeed did mean re-write. >> This guarantee I understand cannot be given by an RTOS alone. It is the >> combined guarantee by the application + RTOS. i.e. everything depends on >> the way the application was developed using the features of an RTOS. > > Comment 1: Ecos has met all hard deadline requirements on our app... > Getting our code to behave has been way more problematical than Ecos. > > Comment 2: Given a choice of a "harder RTOS" than ecos, "misra-c" > kernel, or a faster / smarter CPU with loads of Flash/RAM, I will take > the faster smarter CPU. > > Headroom and flexibility are more important than "guarantees". > Guarantees can be broken, but headroom lets you cope with any broken > guarantees and a lot more besides. > > Comment 3: Most "hard to meet hard deadlines" I have seen have been the > result of > hardware designers saying "lets skimp a bit and fix it in the software". > > So if you have a really hard hard to meet RT deadline, walk over to your > hardware designers and talk to them about life, the universe, safety and > trade offs. > > > > > John Carter Phone : (64)(3) 358 6639 > Tait Electronics Fax : (64)(3) 359 4632 > PO Box 1645 Christchurch Email : john.carter@tait.co.nz > New Zealand > > Carter's Clarification of Murphy's Law. > > "Things only ever go right so that they may go more spectacularly wrong > later." > > From this principle, all of life and physics may be deduced. > -- Regards, Vamshi ------------------------------------------------- R.Vamshi Krishna, M.Tech. CSE (II year), IIT Bombay Room no. 320, A-wing, Hostel-12 Mobile : +919869781633 ------------------------------------------------- Yesterday is a past, tomorrow is a future , today is a gift that's why it's called 'present' -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss