From mboxrd@z Thu Jan 1 00:00:00 1970 To: 9fans@cse.psu.edu Subject: Re: [9fans] micro vs monolithic kernels From: forsyth@caldo.demon.co.uk MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Message-Id: <20010409091150.D186E19A06@mail.cse.psu.edu> Date: Mon, 9 Apr 2001 10:09:11 +0100 Topicbox-Message-UUID: 7bc56578-eac9-11e9-9e20-41e7f4b1d025 >>i seem to remember reading somewhere a reasoning on why it was chosen to >>implement p9 with a monolithic kernel, instead of a micro one.. the implied comparison is false. to start with, the plan 9 kernel is not `monolithic'. it is highly modular. in particular, the interfaces between the kernel and device drivers, and between the IP device driver and its protocol and media drivers, are all narrow, well-structured interfaces. indeed, some things that are implemented by `system calls' in other systems are just separable, configurable device drivers in this one. modularity is not in an `iff' relationship with structuring using message passing and processes. another answer is possibly that they wanted it to do something useful. perhaps there is a connection with cray's comment: If you were plowing a field what would you rather use, 2 strong oxen or 1024 chickens? -Seymour Cray