Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!rutgers!ames!ucbcad!ucbvax!decvax!tektronix!tekcrl!terryl From: terryl@tekcrl.UUCP Newsgroups: comp.sources.wanted,comp.unix.wizards,comp.unix.questions Subject: Re: UUCP Port Turnaround (==> Unix Kernel hacks) Message-ID: <1421@tekcrl.TEK.COM> Date: Fri, 20-Feb-87 17:43:31 EST Article-I.D.: tekcrl.1421 Posted: Fri Feb 20 17:43:31 1987 Date-Received: Sat, 21-Feb-87 16:23:58 EST References: <171@ndmath.UUCP> <4090@nsc.nsc.com> <166@piaget.UUCP> Reply-To: terryl@tekcrl.UUCP (Terry Laskodi) Organization: Tektronix, Inc., Beaverton, OR. Lines: 52 Xref: watmath comp.sources.wanted:597 comp.unix.wizards:1064 comp.unix.questions:1122 In article <395@stracs.cs.strath.ac.uk> jim@cs.strath.ac.uk writes: +In article <3233@rsch.WISC.EDU> mcvoy@rsch.WISC.EDU (Lawrence W. McVoy) writes: +>.. the people at CMU have something called MACH .... It's a message +>passing kernel based on Accent that is binarily compatible with 4.3BSD on +>Vax, source compatible elsewhere. It's supposedly well designed, +>easy to maintain, and has some new features that make Unix look sick (like +>copy-on-write MM, used to get pass-by-value saftey with pass-by-reference +>speed, msg based so networking is cake, user loadable drivers, pagers, etc). + +Granted MACH has lots of interesting things in it, but it is HUGE. Even +a BSD kernel pales into insignificance. I recall someone from CMU saying +that their development kernel had a 700K text segment! OK - it may have +had lots of redundant code for development work, but I can't see how MACH +could be smaller than a comparable Berkeley kernel with all these nice new +ideas that CMU are implementing. I was going to stay out of this, but here are some sizes on /vmunix from various machines I use: text data bss dec hex 192040 88216 98800 379056 5c8b0 /vmunix, VAX 11/780 running 4.3 text data bss dec hex 311108 44472 140656 496236 7926c /vmunix, same VAX running mach text data bss dec hex 253056 24436 69342 346834 54ad2 /vmunix, 68010 workstation with 4.2 text data bss dec hex 246944 30532 39356 316832 4d5a0 /vmunix, 68020 workstation with 4.2 NOTE: these sizes do NOT include all of the data structures allocated dynamically, i.e. disk buffers, in-core inodes, file structs, etc. Also, the workstations are running significantly different flavors of 4.2, with the 68010 workstation more vanilla 4.2. Both workstations also have some sort of remote file system, whereas the VAX does not. Last note: the 68020 workstation kernel was compiled using the Greenhills compiler, whereas the 68010 was compiled with the MIT. I would guestimate that the 68010 kernel would probably shrink by 10-15% by using the Greenhills compiler. +The MACH kernel source might be prettier, but can we afford the extra core +needed to run it? :-) Uh, I hate to burst your bubble, but the MACH sources are definitely NOT prettier. They have made some strides, but unfortunately, there are still a lot of VAX'isms sprinkled throughout the code. Also, MACH hasn't quite split things up into machine-independent and machine-dependent sources, most specifically in the VM subsystem. These observations are from direct experience. Terry Laskodi of Tektronix