From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,8623fab5750cd6aa X-Google-Attributes: gid103376,public Path: g2news1.google.com!news1.google.com!news.glorb.com!cyclone1.gnilink.net!gnilink.net!bigfeed2.bellsouth.net!news.bellsouth.net!elnk-atl-nf1!newsfeed.earthlink.net!stamper.news.atl.earthlink.net!newsread2.news.atl.earthlink.net.POSTED!d9c68f36!not-for-mail Message-ID: <40CEDEBB.3050209@noplace.com> From: Marin David Condic User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 (OEM-HPQ-PRS1C03) X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: Improving Ada's image - Was: 7E7 Flight Controls Electronics References: <40b9c99e$0$268$edfadb0f@dread16.news.tele.dk> <40ba315a$0$254$edfadb0f@dread16.news.tele.dk> <04udnR-eHNChzSbdRVn-vw@gbronline.com> <7J0xc.7371$8k4.269106@news20.bellglobal.com> <1086630278.542788@master.nyc.kbcfp.com> <8xlxc.27603$sS2.845496@news20.bellglobal.com> <1086715817.122983@master.nyc.kbcfp.com> <1086733411.736049@master.nyc.kbcfp.com> <3Auxc.11998$XY6.1296622@read2.cgocable.net> <40C85035.4020706@noplace.com> <40C9EC3B.60304@noplace.com> <40CD90A4.8030005@noplace.com> <1087234490.635201@master.nyc.kbcfp.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Date: Tue, 15 Jun 2004 11:35:01 GMT NNTP-Posting-Host: 209.165.23.116 X-Complaints-To: abuse@earthlink.net X-Trace: newsread2.news.atl.earthlink.net 1087299301 209.165.23.116 (Tue, 15 Jun 2004 04:35:01 PDT) NNTP-Posting-Date: Tue, 15 Jun 2004 04:35:01 PDT Organization: EarthLink Inc. -- http://www.EarthLink.net Xref: g2news1.google.com comp.lang.ada:1497 Date: 2004-06-15T11:35:01+00:00 List-Id: Like I said: The thing that makes operating systems hard to get right are not usually language issues. They are related to the asynchronicity of events and the complexity of the algorithms involved. Perhaps a hypothetical Ada OS might eliminate some errors, but the worst ones are not usually an issue of language checks. Also, because OS's need high efficiency, it is not at all uncommon to turn off most of the runtime checks because you really need the performance. (Or is someone suggesting that all Ada checks should be left in when developing an OS?) Ada can't help with a variety of runtime errors unless the checks are left in, so does it really buy enough benefit to be able to make claims about how wonderful a theoretical Ada OS would be? MDC Hyman Rosen wrote: > Which illustrates that you did not actually bother to read about > what the problem is. The exploit code (which crashes the kernel, > so it's not precisely a security violation) involves user code > which executes a floating-point processor instruction in a signal > handler that should cause a floating-point exception, immediately > followed by a system call. I think that the hardware exception > occurs a little bit later, such that kernel mode has taken over, > and when the kernel goes to restore the floating-point state, the > exception finally kicks in and brings it down. > > I suspect the ultimnate fix involves the kernel checking for > deferred user-mode floating point exceptions so that it can reraise > them in user mode, but in any case, this has nothing to do with the > programming language in which the kernel was written - at the point > of death, it is executing an assembly code insertion. -- ====================================================================== Marin David Condic I work for: http://www.belcan.com/ My project is: http://www.jsf.mil/NSFrames.htm Send Replies To: m o d c @ a m o g c n i c . r "Face it ladies, its not the dress that makes you look fat. Its the FAT that makes you look fat." -- Al Bundy ======================================================================