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,ee887b7593f7961b X-Google-Attributes: gid103376,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news3.google.com!feeder.news-service.com!newsfeed.freenet.de!newsfeed-0.progon.net!progon.net!news-zh.switch.ch!switch.ch!news.ip-plus.net!newsfeed.ip-plus.net!news.post.ch!not-for-mail From: Martin Krischik Newsgroups: comp.lang.ada Subject: Re: Ada OS based on Minix3 Date: Thu, 13 Nov 2008 08:01:46 +0100 Organization: Swisscom IP+ (post doesn't reflect views of Swisscom) Message-ID: <491bd0da$1@news.post.ch> References: <4919431e$1@news.post.ch> <491967de$0$32371$4d3efbfe@news.sover.net> <491973b6$0$32664$9b4e6d93@newsspool2.arcor-online.net> NNTP-Posting-Host: 194.41.146.1 Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Trace: atlas.ip-plus.net 1226559709 4874 194.41.146.1 (13 Nov 2008 07:01:49 GMT) X-Complaints-To: abuse@ip-plus.net NNTP-Posting-Date: Thu, 13 Nov 2008 07:01:49 +0000 (UTC) User-Agent: Thunderbird 2.0.0.17 (Windows/20080914) In-Reply-To: <491973b6$0$32664$9b4e6d93@newsspool2.arcor-online.net> X-Original-NNTP-Posting-Host: w03duo.pnet.ch X-Original-Trace: 13 Nov 2008 08:01:46 +0100, w03duo.pnet.ch Xref: g2news1.google.com comp.lang.ada:2664 Date: 2008-11-13T08:01:46+01:00 List-Id: Hi Georg, Georg Bauhaus schrieb: > Peter C. Chapin schrieb: >> Martin Krischik wrote: >> >>> Now, if I wanted to create an OS I would not target real hardware at >>> all. At least not in the beginning. I would probably implement the OS >>> inside a VMware virtual machine. >> What about targeting a hypervisor like Xen? If I understand correctly >> (and I may not) that would separate the OS somewhat from the real >> hardware and may help its portability in the long run. > How could separation from the hardware do better than a > Microkernel such as Minix 3? Speaking of Microkernel: what ever happened to the ring concept? Why this all (ring 0) and nothing (ring 3) everywhere? After all one of the most stable OS's - ever - used 4 privilege modes: http://en.wikipedia.org/wiki/VAX#Privilege_Modes privilege mode. Interesting to see that the File System runs in it's own mode - especially when one considers the recent FUSE development. Using 4 privilege modes certainly would be something I would investigate when trying out OS design. > Full virtualization also deprives you of access to > a larger set of hardware. Which, I'd speculate, is not > too helpful when targeting mostly embedded system? Actually I see the "larger set of hardware" as a disadvantage for a new OS. For a small OS with a few or only one developers the is just not enough horse power to produce tons and tons of different device driver. With full virtualization you just have one set of hardware to produce device driver for which leaves you with more time for the interesting things like new revolutionary OS design. Regards Martin -- mailto://krischik@users.sourceforge.net Ada programming at: http://ada.krischik.com