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From: daveh@cbmvax.cbm.UUCP (Dave Haynie)
Newsgroups: net.micro.mac
Subject: Re: Multitasking
Message-ID: <627@cbmvax.cbmvax.cbm.UUCP>
Date: Thu, 14-Aug-86 14:34:50 EDT
Article-I.D.: cbmvax.627
Posted: Thu Aug 14 14:34:50 1986
Date-Received: Sun, 17-Aug-86 05:43:45 EDT
References: <154@uwmacc.UUCP>
Organization: Commodore Technology, West Chester, PA
Lines: 60

> 
> 
>      A debate over multitasking crops up occasionally, with some
> claiming it really has little use, while others insisting it is
> essential for efficient use of a computer. One argument for mutitasking
> is that it permits you to do something else on your computer while
> waiting for it to compile code or recalculate a spreadsheet.  But
> wouldn't it be far preferable to use a compiler or spreadsheet that is
> fast enough that any wait is negligeable and your train of thought is
> not broken.  Multi- tasking would only slow a slow program down and
> break your thought even more. Turbo Pascal and Lightspeed C show that
> sufficiently fast compilers, at least, are possible, even on not
> especially fast machines.  And the success of these compilers suggests
> that many people appreciate being able to test code out quickly in a
> more interactive manner than possible with traditional compilers.   The
> popularity of interpreted Basic and even the relatively modest interest
> in Forth, in spite of the disadvantages of these languages, also
> support the idea that people prefer to program inter- actively.  I
> think it is even claimed in some quarters that interactive programming
> is more efficient than batch programming, though I don't know if this
> notion has been tested objectively.  It's true, of course, that you do
> need to take breaks occasionally from coding, but I would rather choose
> my own times rather than have them imposed by a slow compiler.
>      Certainly it would be nice to be able to download or print files
>      in the background, though personally I find printing on a noisy
> dot matrix printer a good time to stretch my legs and leave the room,
> but I thought these tasks were possible on almost any computer.  I once
> had a DA called Multitasking Print (I think) which permitted printing
> text files in the background while compiling (in Rascal). It always
> worked without a hitch until a faulty disk drive destroyed my only
> copy.  Whatever happened to that DA, by the way, I haven't seen it
> around again.

Older machines are not well suited for multitasking for some of the reasons
you mention.  But on modern 68000 machines on up, much of the processor's
bandwidth is wasted waiting for slow I/O operations to complete.  No matter
how fast you think your disk drive is, its still sitting still compared to
the processor.  Thus, you can conceivably run two or more programs at the
same speed that each would run alone.  Sometimes multitasking does nothing
more than give you a generalized switcher; you might not likely compile
and edit the same file simultaneously, but you could keep the editor in
memory while compiling, or even call the compiler from the editor.  Such
a system also allows business types to build their own integrated package
(assuming some standard file interchange format) instead of settling for
weak versions available in the all-in-one style package.  

I've used Amiga 68000 based machines, Apollo 68010, and VAX systems with
multitasking, and in every case, I've found it more productive than
working on a single tasking machine, and by a long shot.

-- 
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Dave Haynie    {caip,ihnp4,allegra,seismo}!cbmvax!daveh

	"I gained nothing at all from Supreme Enlightenment, and
	 for that very reason it is called Supreme Enlightenment."
							-Gotama Buddha

	These opinions are my own, though for a small fee they be yours too.
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