Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!radar!cantor!tulloh From: tulloh@cantor.ACA.MCC.COM (Robert Tulloh) Newsgroups: comp.sys.amiga Subject: Re: Multifinder - Just the Facts, man. Summary: multitasking NOT parallel processing! Message-ID: <43@cantor.ACA.MCC.COM> Date: 4 May 90 17:13:12 GMT References: <20499@boulder.Colorado.EDU> <8930@hubcap.clemson.edu> <1990May3.042500.18758@wam.umd.edu> Organization: MCC, Austin, TX Lines: 54 In article <1990May3.042500.18758@wam.umd.edu>, ddev@wam.umd.edu (Don DeVoe) writes: > In article <7416@wehi.dn.mu.oz> BAXTER_A@wehi.dn.mu.oz writes: > >In article <43785@iuvax.cs.indiana.edu>, sl195091@silver.ucs.indiana.edu (Andy Hartman) writes: > >> In article <10143@sdcc6.ucsd.edu> cs163wed@sdcc10.ucsd.edu (see far) writes: > >> > >>> > >>>ISn't the AMiga's multi-tasking program swapping? Unless you have > >>>several amigas at once, you can never run programs simultaneously. > >>>Amiga's multitasking only tricks you into thinking it is running > >>>programs "simultaneously". > >>> > >>>After all, you get only one 68000 in an amiga, don't you? > >> > > > >Youre right, Andy. > >This drongo doesn't know the difference between multitasking and parallel > >processing. > > Tell us, just what is the difference? In a strict sense, you can't have > (true) multitasking without multiple processors...anything else is just > program swapping; multitasking is implicitly denied in a single processor > system. And just what is a drongo, anyway? > > > -- > Don DeVoe Perhaps it depends on your definition of multitasking. So here is one for your approval/disapproval... Multitasking is the process by which an O/S can manage one or more processes running concurrently, but never any two programs executing at the same time. Each process gets a timeslice of CPU time with the size of the slice dependent on task priorities, the number of tasks executing, and the nature of the executing tasks (some tasks simply don't need to execute when it is their turn). So, you don't need more than one CPU to multitask. True multitasking implies the O/S is controlling who gets to execute when, not the programs that are running under it. Thus, on a multitasking system, you don't have to write programs which have to worry about giving up the CPU to other programs since you know that the O/S will handle this little job for you ( :-). I contend that with multiple processors you then have distributed or parallel processing (no, I don't mean these are the same thing). These environments can also be multitasking (and they usually are!). Rob Tulloh MCC, Deductive Computing | ARPA : tulloh@mcc.com | Phone: (512) 338-3704 3500 West Balcones Center Dr. | UUCP : ...!cs.utexas.edu!hippo!cantor!tulloh Austin, TX 78759 | GENIE: R.TULLOH -- MCC, Deductive Computing | ARPA: tulloh@mcc.com | Phone: (512) 338-3704 3500 West Balcones Center Dr. | UUCP: ...!cs.utexas.edu!mcc.com!cantor!tulloh Austin TX 78759 | GENIE: R.TULLOH