Path: utzoo!utgpu!attcan!uunet!cbmvax!daveh From: daveh@cbmvax.UUCP (Dave Haynie) Newsgroups: comp.sys.amiga Subject: Re: Amiga UNIX Message-ID: <5010@cbmvax.UUCP> Date: 17 Oct 88 17:59:30 GMT References: <3400@leo.UUCP> Organization: Commodore Technology, West Chester, PA Lines: 61 in article <3400@leo.UUCP>, harald@leo.UUCP ( Harald Milne) says: > Keywords: Multi OS? > I heard from at least 3 different sources that Amiga UNIX and > Amigados (and MSDOS) all run simultaniously on the Amiga. > Well I know Amigados and MSDOS do, but UNIX? No. What seems to have precipitated this was the demo given by Dr. Rubin at the last Comdex. At the Commodore press conference, he was showing off some Amiga OS stuff, then clicked on the UNIX icon, and up comes UNIX. While it was explained that switching on UNIX is really a "world swap", if you see the demo, it sure enough looks like UNIX is coming up as an Amiga screen. > From reading the A500/A2000 Technical Reference Manual from CBM, > it appears that the coprocessor slot has 2 modes of DMA operation. > From what I understand, the standard 68000 AND coprocessor slot (like > CBM's A2620 68020 card with MMU) can both MASTER the bus independently. But not simultaneously. If the CPU slot device wants control of the bus, it requests the bus from the 68000, much like any expansion bus device would. In the second mode, though, it gets all expansion bus DMA requests routed to it, so it's a master fully equivalent to the 68000 in every respect. > In that case, UNIX could run side by side with Amigados, BOTH running > at the same time. They could share the same hard disk controller, (or > separate controllers). In the Zorro I expansion architecture, a coprocessor > would effectively block the standard 68000 from being a bus master at all. > But the Zorro II expansion allows BOTH to run to run at the same time. With local RAM on a CPU slot card, you could run both that card and the 68000 simultaneously. There are, however, many complexities in doing this. For instance, an interrupt comes along. Who services it, or do both CPUs try. Or if the CPU slot needs lots of chip memory access, the 68000 may never get any. The hardware protocols are there to allow two CPUs running basically at the same time, but no one's yet taken advantage of this with software. The A2620 uses this feature to optionall boot AmigaOS with the 68000 in charge, rather than the 68020. But once you're running, you're dedicated to one or the other CPU (based on the way the A2620 hardware works). > Am I dreaming or what. > You can play games and run UNIX at the same time? Not quite. Unless it's rogue or another UNIX game :-). > Na, I must be dreaming. I'll go back to sleep. If anyone wants to do a 3rd party UNIX.... > Work: Computer Consoles Inc. (CCI), Advanced Development Group (ADG) > Irvine, CA (RISCy business!) > UUCP: uunet!ccicpg!leo!harald -- Dave Haynie "The 32 Bit Guy" Commodore-Amiga "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: D-DAVE H BIX: hazy "I can't relax, 'cause I'm a Boinger!"