Date: Wed, 27 Mar 1996 11:23:40 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: sclawson@bottles.cs.utah.edu (steve clawson) Cc: babkin@hq.icb.chel.su, dgy@rtd.com, mikebo@tellabs.com, freebsd-hackers@freefall.freebsd.org Subject: Re: OSF Micro Kernel for Linux/FreeBSD/etc Message-ID: <199603271823.LAA01607@phaeton.artisoft.com> In-Reply-To: <199603270840.BAA11882@bottles.cs.utah.edu> from "steve clawson" at Mar 27, 96 01:40:43 am
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> OSF/1 MK is a serverized version of OSF/1, the same as Mach > 3.0/UX is the serverized version of Mach 2.x. Basically they took the > code that was above the Mach layer and moved it into a server, just > keeping the Mach abstractions in the kernel. However, lately even > OSF/1 MK has been doing ``In Kernel Servers'', where they move the > server back into the kernel's address space and sort-circuit the RPC's > (turn them into function calls) to get better performance. Message overhead is the reason that Chorus changed tactics (Chorus is a "competing" microkernel that USL was using to implement the next version of System V after SVR4.2 was released; it ran "NetWare" and "UnixWare" personalities simultaneously). The amount of protection domain crossing in MACH is prohibitive for anything but monolithic servers... the performance just isn't there otherwise. Chorus source code is available for University licensing at $1000 a pop. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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