Path: utzoo!attcan!uunet!snorkelwacker!apple!oliveb!orc!decwrl!argosy!jay From: jay@argosy.UUCP (Jay O'Conor) Newsgroups: comp.arch Subject: Re: Macintosh OS Message-ID: <575@argosy.UUCP> Date: 12 Jun 90 21:31:24 GMT References: <1990May30.230248.6200@Neon.Stanford.EDU> <1935@key.COM> <30273@ut-emx.UUCP> <76700207@p.cs.uiuc.edu> <402@newave.UUCP> <1990Jun2.132847.14292@oracle.com> <26437.266ae612@vaxb.acs.unt.edu> <1682@mcrware.UUCP> <12539@cbmvax.com Sender: news@argosy.UUCP Reply-To: jay@idiot.UUCP (Jay O'Conor) Organization: MasPar Computer Corporation, Sunnyvale, CA Lines: 21 In article <12539@cbmvax.commodore.com> daveh@cbmvax (Dave Haynie) writes: >For every context swap, all kinds of this global context information must be >stored somewhere. The preemptive system need only store CPU context >information -- program counter and various registers. You're not serious, are you? You don't really mean to imply that "program counter and various registers" are all there is to a process' context? I'll grant that the Mac O/S is currently somewhat unweildy in identifying everything that constitutes a process context, but every O/S I'm aware of has more than just processor registers that define a process context. Whether the multitasking system is preemptive or cooperative has no effect on what a process' context is. Preemptive multitasking systems can have just as much context information as a cooperative multitasking system - it's just that the context must be private to the process in a preemptive scheduler, while much of the context can be global with a cooperative scheduler. Jay O'Conor jay@maspar.com