DAVEA%CERNVM.BITNET@cunyvm.cuny.edu (David Almond) (04/10/89)
> In that the amiga has dedicated processers for graphics etc it is, to some > degree multitasking, but not in any sophisticated, scheduled sense. >>>Do you write for BYTE, by any chance? That's dead wrong, on every account. >>>The Amiga is FULLY multitasking, in the sense that the processor is time >>>sliced among many processes. Much in the same vein as UNIX, OS/9, Aegis, >>>VMS, etc. No, if I did the sales would soar. What I meant to say, and not wishing to burn precious space, is that the though the Amiga is multitaskingfor all the reasions you outlined is not fully multitasking beause there is no scheduler which controls overall running of tasks. So that it would no how much spare capacity exists on each intelligent processing device, as it processes, and thus be able to dispatch the next processing task in the most efficent manner. Now I know the Amiga is good, but its not that good .... nes pa ....... Dave
martens@ketch.cis.ohio-state.edu (Jeff Martens) (04/10/89)
In article <12700@louie.udel.EDU> DAVEA%CERNVM.BITNET@cunyvm.cuny.edu (David Almond) writes:
:: In that the amiga has dedicated processers for graphics etc it is, to some
:: degree multitasking, but not in any sophisticated, scheduled sense.
::::Do you write for BYTE, by any chance? That's dead wrong, on every account.
::::The Amiga is FULLY multitasking, in the sense that the processor is time
::::sliced among many processes. Much in the same vein as UNIX, OS/9, Aegis,
::::VMS, etc.
: No, if I did the sales would soar. What I meant to say, and not wishing
:to burn precious space, is that the though the Amiga is multitaskingfor
:all the reasions you outlined is not fully multitasking beause there
:is no scheduler which controls overall running of tasks. So that it
:would no how much spare capacity exists on each intelligent processing
:device, as it processes, and thus be able to dispatch the next processing
:task in the most efficent manner.
You're confused. For the reasons the other poster outlined, the Amiga
does have a full-blown scheduler: tasks are started, stopped,
time-sliced, and prioritized. What else do you want from a scheduler?
Certainly the Amiga scheduler "controls the overall" scheduling "of
tasks." ----------
I'm not sure what you meant by "spare capacity...", but most OS
schedulers aren't brilliant, and don't do much more. You may be
thinking of resource tracking or protection, which the Amiga does
lack, but these wouldn't be part of the scheduler anyhow.
-=-
-- Jeff (martens@cis.ohio-state.edu)
...and on Wall St., the Tao is unchanged in moderate trading...elg@killer.Dallas.TX.US (Eric Green) (04/12/89)
in article <12700@louie.udel.EDU>, DAVEA%CERNVM.BITNET@cunyvm.cuny.edu (David Almond) says: > to burn precious space, is that the though the Amiga is multitaskingfor > all the reasions you outlined is not fully multitasking beause there > is no scheduler which controls overall running of tasks. So that it > would no how much spare capacity exists on each intelligent processing > device, as it processes, and thus be able to dispatch the next processing > task in the most efficent manner. Say WHAAA??? are you SURE that you don't work for BYTE??? (Yes, I know that you denied it -- but this is typical of Byte misinformation). The Amiga DOES have a central task scheduler -- what do you think Exec is? Now, there's a few problems with the Amiga's task scheduler -- it allows high priority processes to hog all of the CPU without dribbling any down to low priority processes, in the event that the programmver of the high priority process puts a wait loop instead of a Wait() call. But that is irrelevant to the average user (who runs all of his programs at priority 0, where un-blocked tasks are timesliced equally), and perfect for real-time work (which is what Exec was designed for in the first place). So, while the Amiga's task scheduler isn't of the level of, say, the Multics task scheduler (which took into account size of program, how many keys you typed in the last few minutes, and lots of other esoteric info -- I kid you not), it DOES have one. Or perhaps you wanted to say "let other processes run while you're using the blitter"? Look at the QBlit () routine in graphics.library, which allows you to queue blitter requests. Or WaitBlit() which puts your process to sleep while your blitter request is going (thus letting other programs run). Or.... well, you get the picture. Or perhaps you wanted to say, "have the disk handler queue requests & sort them so that the disk drive doesn't gronk"? That has nothing to do with the multitasking ability of the Amiga -- just with a very badly designed disk handler (:-(). The Amiga is multitasking. Period. It's the multi-processing part that's only "semi" (the blitter and copper aren't "real" processors, but they "sort of" count). And while the internals of the process scheduler would require work for a multi-processor Amiga, a shared-memory multi-processor AmigaDOS would work just fine (just as long as you have write-through caches, & bus-sniffing). -- | // Eric Lee Green P.O. Box 92191, Lafayette, LA 70509 | | // ..!{ames,decwrl,mit-eddie,osu-cis}!killer!elg (318)989-9849 | | \X/ Amiga. The homestation for the blessed of us. |
keithh@atreus.uucp (Keith Hanlan) (04/13/89)
In article <42406@tut.cis.ohio-state.edu> Jeff Martens <martens@cis.ohio-state.edu> writes: >In article <12700@louie.udel.EDU> DAVEA%CERNVM.BITNET@cunyvm.cuny.edu (David Almond) writes: > >:: In that the amiga has dedicated processers for graphics etc it is, to some >:: degree multitasking, but not in any sophisticated, scheduled sense. > >::::The Amiga is FULLY multitasking, in the sense that the processor is time >::::sliced among many processes. Much in the same vein as UNIX, OS/9, Aegis, >::::VMS, etc. > >:to burn precious space, is that the though the Amiga is multitaskingfor >:all the reasions you outlined is not fully multitasking beause there >:is no scheduler which controls overall running of tasks. So that it >:would no how much spare capacity exists on each intelligent processing >:device, as it processes, and thus be able to dispatch the next processing >:task in the most efficent manner. I think the confusion is that Mr. Martens is talking about *multi-processing* but calling it multi-tasking. Yes the amiga is a multi-processing computer in that it has multiple processors but it is not multi-processing in the same sense as a multi-CPU machine. This is hardly surprising. The co-processors are dedicated function chips. Does this clear things up? Keith Hanlan {uunet!attcan!}utgpu!bnr-vpa!bnr-fos!atreus!keithh Bell-Northern Research Ottawa, Canada
martens@cis.ohio-state.edu (Jeff Martens) (04/14/89)
In article <397@bnr-fos.UUCP> Keith Hanlan writes: >In article <42406@tut.cis.ohio-state.edu> Jeff Martens <martens@cis.ohio-state.edu> writes: :>In article <12700@louie.udel.EDU> DAVEA%CERNVM.BITNET@cunyvm.cuny.edu (David Almond) writes: :> :>:: In that the amiga has dedicated processers for graphics etc it is, to some :>:: degree multitasking, but not in any sophisticated, scheduled sense. :> :>::::The Amiga is FULLY multitasking, in the sense that the processor is time :>::::sliced among many processes. Much in the same vein as UNIX, OS/9, Aegis, :>::::VMS, etc. :> :>:to burn precious space, is that the though the Amiga is multitaskingfor :>:all the reasions you outlined is not fully multitasking beause there :>:is no scheduler which controls overall running of tasks. So that it :>:would no how much spare capacity exists on each intelligent processing :>:device, as it processes, and thus be able to dispatch the next processing :>:task in the most efficent manner. > I think the confusion is that Mr. Martens is talking about > *multi-processing* but calling it multi-tasking. > Yes the amiga is a multi-processing computer in that it has multiple > processors but it is not multi-processing in the same sense as a > multi-CPU machine. This is hardly surprising. The co-processors are > dedicated function chips. > Does this clear things up? > Keith Hanlan {uunet!attcan!}utgpu!bnr-vpa!bnr-fos!atreus!keithh > Bell-Northern Research > Ottawa, Canada No, this muddies it up. Although none of my posting was repeated (so I think you were attributing to me what soemone else said), I was talking about multasking, as was the person quoted above who pointed out that Unix, VMS, etc. multitask in the same sense as the Amiga (and vice-versa). Multiprocessing is the use of multiple processors; the Amiga does this in a very asymmetric sense since there are processors inside dedicated to screen handling and the like. Symmetric multiprocessing would require more than one 68000, which my Amiga doesn't have. Multitasking, on the other hand, just means there can be more than one thread of control at a time. See any intro undergrad OS text, like Deitel's. My main objection was to the person who claimed that the Amiga doesn't have a scheduler; this is clearly false. On a second read through keithh's posting, perhaps he meant that the person I was responding to (the person quoted above as claiming the Amiga isn't fully multitasking) was confused between multitasking and multiprocessing. If so, maybe he should just pay more attention to who said what. -- -- Jeff (martens@cis.ohio-state.edu) ....and on Wall St., the Tao is unchanged in moderate trading...
kim@beowulf.ucsd.edu (Geoffrey K Kim) (04/14/89)
In article <397@bnr-fos.UUCP> keithh@atreus.UUCP (Keith Hanlan) writes: > > I think the confusion is that Mr. Martens is talking about > *multi-processing* but calling it multi-tasking. > Unfortunately I think this confusion was brought about by certain computer and software manufacturers that ended up *bastardizing* the term 'multi-tasking'. PROVIDING A MANUAL TASK SWITCHING CAPABILITY IS *NOT* TRUE MULTI-TASKING! Sorry, I just had to get that off my chest. Now I feel better, thank you. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | kim @beowulf.UCSD.EDU (Home of the Garden Weasles) | | "... ENGAGE!" -- Jean Luc Picard, STTNG | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
rwallace@vax1.tcd.ie (04/21/89)
In article <7819@killer.Dallas.TX.US>, elg@killer.Dallas.TX.US (Eric Green) writes: > in article <12700@louie.udel.EDU>, DAVEA%CERNVM.BITNET@cunyvm.cuny.edu (David Almond) says: >> to burn precious space, is that the though the Amiga is multitaskingfor >> all the reasions you outlined is not fully multitasking beause there >> is no scheduler which controls overall running of tasks. So that it >> would no how much spare capacity exists on each intelligent processing >> device, as it processes, and thus be able to dispatch the next processing >> task in the most efficent manner. > > Say WHAAA??? are you SURE that you don't work for BYTE??? (Yes, I know > that you denied it -- but this is typical of Byte misinformation). > > The Amiga DOES have a central task scheduler -- what do you think Exec > is? Of course the super-smart mainframe OS task schedulers which can share out .001 MIPS of processing power more fairly among tasks will gobble up a hundred times that much processing power because they're so inefficiently written. At least on the Amiga almost all the processor time actually goes to the tasks not the multitasking system. "To summarize the summary of the summary: people are a problem" Russell Wallace, Trinity College, Dublin rwallace@vax1.tcd.ie