larryw@dasys1.UUCP (Winston Lawrence) (12/31/87)
I think that this discussion is a little off-base in many ways. Would this be going on if we were debating the benefits of disk versus cassette storage?
You will be hard pressed to find ANY microcomputer of recent vintage that does NOT multitask to some extent. The Atari 8bits use multitasking. The ANTIC CPU interrupts the 6502 chip to generate the video. Smart programs turn OFF the multitasking during cpu intensive stuff (compiles for example) to speed things up, or write special multitasking programs (graphic displays). The POKEY sound chip works in a similar manner for the sound output. Disk controllers use dedicated chips (and DMA) to do their thing while the CPU does its thing. ON PCs, IRMA boards handle screen i/o and updates IN THE BACKGROUND, regardless of what you are doing in DOS. While you might split hairs as to whether this is multitasking,
parallel processing, or networking. Its a moot point. Multitasking is real,
is here, and has been a feature on most micros for the last six or seven years.
As fo Joe user - Mr Average - They may not buy computer systems as we use them, but have you looked into their cars nowadays? Computer controlled emission systems, fuel control and ignition, mileage calculators etc? All of these systems arehappily multitasking away in real time too (they better be). PS before I get flames that these automobile systems are not programmable, some of the hottest underground programming jobs right now is REPROGRAMMING these things to beef up the
cars performance (usually at the expense of emission standards) and the feds areseriously thinking about outlawing the chips and making their reprogramming illegal.
:x
:q
:X
--
Winston Lawrence {allegra,philabs,cmcl2}!phri\
Big Electric Cat Public Unix {bellcore,cmcl2}!cucard!dasys1!larryw
New York, NY, USA {sun}!hoptoad/ dillon@CORY.BERKELEY.EDU (Matt Dillon) (01/01/88)
: I think that this discussion is a little off-base in many ways. Would :this be going on if we were debating the benefits of disk versus cassette :storage? : You will be hard pressed to find ANY microcomputer of recent vintage :that does NOT multitask to some extent. The Atari 8bits use multitasking. :The ANTIC CPU interrupts the 6502 chip to generate the video. Smart programs :turn OFF the multitasking during cpu intensive stuff (compiles for example) :to speed things up, or write special multitasking programs (graphic :displays). The POKEY sound chip works in a similar manner for the sound :output. Disk controllers use dedicated chips (and DMA) to do their Ever heard of newlines? You paragraphs were all one single line! I think *you* are slightly off base a little here. Every microcomputer down h to the old Apple II's (and older) has interrupts. Interrupts and DMA does not a multitasking computer make. I think the definition everybody has had in mind throughout this affair has been: -preemptive scheduling -each 'task' is an independant entity with no restrictions relative to other tasks (Read: Not an interrupt, Not DMA) -The OS supports the fact with signaling, control, and communications calls, is reentrant, etc... The overall idea being that you can then run completely independant applications simultaniously. After all, any semi intelligent hacker can write a simple context switcher for his or her particular program. Now this business of running more than one application at a time has been argued to be not all that big a deal. Even discarding the rather silly arguments over exactly what one would want to run simultaniously, multitasking has distinct advantages in other areas. Take a look at the number of problems multitasking simplifies (things you CAN DO NOW with hacks or complex programming): -DA's (graphical clocks, calculators, etc...) -Printer spoolers -Networking -Asynchronous IO -Multi-line BBS's **without** delays -program debugging -OS hacks (hot keys and other items) Looking at the amount of money and time Apple has invested attempting to match the Amiga's multitasking. Even if you don't give a bull's toe for the Amiga it should be obvious that the future of microcomputers is turning towards multitasking. Look at (Bletch) OS II for the IBM! If anybody has ever had a rock solid will-never-change attitude it has been IBM. As I said, the above can be done NOW on the Atari, but it takes a lot of work, and many incompatibilities crop due to the lack of a standard way of doing some of the above. I think that simply adding a couple OS calls to support a rudimentry multitasking (to go beyond Apple's task switching) would be a big boon! The first step is to share the CPU. -Matt
andrew@dasys1.UUCP (Andrew Huie) (01/02/88)
In article <2406@dasys1.UUCP>, larryw@dasys1.UUCP (Winston Lawrence) writes: > > I think that this discussion is a little off-base in many ways. Would this be going on if we were debating the benefits of disk versus cassette storage? > You will be hard pressed to find ANY microcomputer of recent vintage that >does NOT multitask to some extent. The Atari 8bits use multitasking. The ANTIC >CPU interrupts the 6502 chip to generate the video. Smart programs turn OFF the >multitasking during cpu intensive stuff (compiles for example) to speed things I think you're confusing interrupt processing with full multitasking. One question you can ask yourself is: Can I run more than one program from the same microprocessor? Or can I interchange programs between processors? The answer: NO. Each chip is only capable of dealing with one task at a time, and only a task specific to that chip. A real multitasking machine can have the microprocessor (e.g. 68000) deal with more than one task on a revolving basis, using priorities to see who gets more time, without having to wait for each task to finish completely before starting the next one. If the computer isn't too slow or weighted down (with tasks), this can appear to the user as if each task is running at exactly the same time. >works in a similar manner for the sound output. Disk controllers use dedicated >chips (and DMA) to do their thing while the CPU does its thing. ON PCs, IRMA >boards handle screen i/o and updates IN THE BACKGROUND, regardless of what you >are doing in DOS. While you might split hairs as to whether this is multitasking, > parallel processing, or networking. Its a moot point. Multitasking is real, > is here, and has been a feature on most micros for the last six or seven years. If you want to call interrupt processing multitasking, then of course computers have had it for many years, but it definitely isn't the kind that's going to, by itself, allow you to run more than one of your favorite applications at the same time. > > -- > Winston Lawrence {allegra,philabs,cmcl2}!phri\ > Big Electric Cat Public Unix {bellcore,cmcl2}!cucard!dasys1!larryw > New York, NY, USA {sun}!hoptoad/