Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!samsung!olivea!mintaka!dcw From: dcw@lcs.mit.edu (David C. Whitney) Newsgroups: comp.sys.apple2 Subject: Re: Apple II / Mac discusson (was:Re:Official"No New Apple II's") Message-ID: <1990Nov5.132240.27492@mintaka.lcs.mit.edu> Date: 5 Nov 90 13:22:40 GMT References: <9011040755.AA25630@apple.com> Sender: daemon@mintaka.lcs.mit.edu (Lucifer Maleficius) Organization: MIT Spoken Language Systems Group Lines: 38 In article <9011040755.AA25630@apple.com> MQUINN%UTCVM@PUCC.PRINCETON.EDU writes: > >About the Multifinder and 'multitasking'.... I completely agree with you. >Switching between aplications is NOT multitasking.... Having two applications >both RUNNING at the SAME appearant time IS multitasking, which the Mac does >not do. OOPS. Wrong, but thanks for playing. MultiFinder is about as much multitasking as can be done non-preemptively (sp?). I know that you can run two (or 3 or 8) programs at once, and have them all chugging away on their own little numbers at once 'cause I've done it and I've written programs that do it. This discussion is pointless because everyone is going to argue about what is/isn't multitasking. MultiFinder is, but it isn't "safe" or "complete." It's not safe in that there's no memory or process protection. My program could easily trash another program's code or data. If my program crashes, it'll take down the whole machine. At the same time, in order for the multitasking to take place, my program must cooperate. Unix has all these problems solved - but solving the problems doesn't raise the OS to "true multitasking" levels. The Mac OS has made attempts to prevent these sorts of things from happening. Anyone who writes programs using MacAPP will be MultiFinder-compliant. Also, anyone who checks memory allocations to be sure it went OK won't be trashing random parts of memory. There are bits in an app's resource that indicate how much memory the app thinks is in the machine. The memory manager won't let the app allocate more than that amount. MultiFinder isn't just program switching - it really is cheap multitasking. Now, the GS can do this too. Leapfrog demonstrated this. By the way, have there been any more advances to Leapfrog? -- Dave Whitney Computer Science MIT 1990 | I wrote Z-Link and BinSCII. Send me bug dcw@lcs.mit.edu | reports. I need a job. Send me an offer. Every now and then one makes a mistake. Mine was probably this post.