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-Thread: 103376,b95a522100671708 X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news4.google.com!news.glorb.com!border1.nntp.dca.giganews.com!border2.nntp.dca.giganews.com!nntp.giganews.com!feed.cgocable.net!read1.cgocable.net.POSTED!53ab2750!not-for-mail From: "Warren W. Gay VE3WWG" User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.2) Gecko/20040804 Netscape/7.2 (ax) X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: For the AdaOS folks References: <1PTAd.1218$0y4.421@read1.cgocable.net> <1vemlj8wqr9ea$.qyecszhsmtqa$.dlg@40tude.net> <1b48kdfqsk3mw.7gajq12fsa82.dlg@40tude.net> <52fBd.42256$nV.1324414@news20.bellglobal.com> <33li96F422q0fU1@individual.net> <33qh7eF42pn2fU1@individual.net> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Message-ID: Date: Mon, 03 Jan 2005 10:52:45 -0500 NNTP-Posting-Host: 24.150.168.167 X-Complaints-To: abuse@cogeco.ca X-Trace: read1.cgocable.net 1104767498 24.150.168.167 (Mon, 03 Jan 2005 10:51:38 EST) NNTP-Posting-Date: Mon, 03 Jan 2005 10:51:38 EST Organization: Cogeco Cable Xref: g2news1.google.com comp.lang.ada:7407 Date: 2005-01-03T10:52:45-05:00 List-Id: Luke A. Guest wrote: > On Sun, 02 Jan 2005 22:13:47 -0500, Warren W. Gay VE3WWG wrote: >>>>>Correct. That's why a protected AmigaOS must support protection domains >>>>>not only for processes but also for libraries. That's a generalization >>>>>of the UNIX model. There you have protection domains for each process >>>>>plus one protection domain for the kernel which is mainly a huge >>>>>library. In AmigaOS every library would need its own protection domain >>>>>and context switches must be as lightweight as possible. >>> >>>I certainly wouldn't do it like that. On hardware that has an MMU (most >>>these days), that would result in a very slow system due to the amount of >>>context switches, this is why the libraries need to be mapped into the >>>address space of the running app, i.e. shared between applications. >> >>There is no argument about the overhead in this case. However, I >>maintain that if enough people start using operating systems >>that are implemented this way, they'll finally enhance the >>hardware to correct this problem. Until then, people may as well >>continue to say "we can't do it that way". I believe the problem >>is fixable in hardware. > > Yeah but, what you were saying was that you wanted OSes to use protection > domains for libraries *as well*, this is the wrong way to go. The > libraries are (and should be) mapped into an applications address space, > libraries *should never* have their own address spaces. It is that idea > which is wrong and would be slow, not the *proper* way to do it. Oh, no - I don't know where you got that from (perhaps you've mixed me up with a different poster). Shared libraries have an important role to play. -- Warren W. Gay VE3WWG http://home.cogeco.ca/~ve3wwg