Path: utzoo!utgpu!attcan!uunet!lll-winken!lll-tis!ames!mailrus!cornell!rochester!daemon From: @DOUGHNUT.CS.ROCHESTER.EDU:miller@CS.ROCHESTER.EDU Newsgroups: comp.sys.mac Subject: Re: System 8.0: no more DA's. Message-ID: <1988Dec14.223739.16280@cs.rochester.edu> Date: 15 Dec 88 03:37:39 GMT Organization: U of Rochester, CS Dept, Rochester, NY Lines: 29 From: Brad Miller Date: 14 Dec 88 05:34:43 GMT From: c60a-2ce@e260-2b.berkeley.edu (Mikey) Also, someone mentioned multitasking? Will system 8.0 support TRUE multi- tasking? I thought this was only possible with a Mac IIx or an appropriately upgraded Mac that supports virtual memory. You can multitask without virtual memory. The problem with the 68000 is that it doesn't save enough internal state to be able to handle page faults, thus you can't do virtual memory. The ability to run more than one process (ie. multitasking) is a different issue entirely. Of course, it is an environment much as multifinder is, all processes must be resident, and one can only task switch at "safe" points, as opposed to an arbitrary interrupt, (e.g. during i/o the process purposely saves it's state to be resumed later) again because of limitations on the 68000 and its internal state. But people were doing multitasking before they were doing virtual memory... It's something of a pity multifinder doesn't already do this; one could have a reasonable yet small IPC standard based on pointers to heap objects... and then consumers of a stream could run simultaneously with the producer, rather than the current braindamage of producing a file, switching to the next program, reading the file... Ah well, PCs for the most part haven't entered into late 70s technology... ---- Brad Miller U. Rochester Comp Sci Dept. miller@cs.rochester.edu {...allegra!rochester!miller}