jafischer@watrose.UUCP (01/22/87)
In article <636@mit-amt.MEDIA.MIT.EDU> ralph@ATRP.MEDIA.MIT.EDU (Amiga-Man) writes: > ... [talks about advantages of Amiga] >- A true multitasking OS. I find this feature very important. I'm really curious: just how great is multitasking? I.e., how much do you, the typical Amiga owners, use this feature? Even on Unix I find that the only thing I consistently use '&' for is printing, and on my ST I have a wide range of print spoolers to choose from. And when I'm in the edit-compile-edit cycle, the speed of Megamax compile-time, coupled with a RAMdisk, makes multi- tasking a 'yeah it would be nice, but not utterly world-stopping' luxury. (There is a multitasking C-Shell, but it's basically non-GEM, and still pretty buggy). But then again... I _don't_ envy your high (until recently) prices, nor your apparently buggy OS (see message 1292 in comp.sys.amiga!), but... I _DO_ envy your multitasking! I'm just curious how useful it actually is. I.e., is it that necessary in a personal computer, and is it worth the slow-down in execution? Even though I would really _like_ it, would I really use it that much? Uh oh, this could be taken as a typical my-PC-is-better-than-yours posting. It isn't. The main intent of this posting is the question of multitasking. - Jonathan Fischer
grr@cbmvax.cbm.UUCP (George Robbins) (01/23/87)
In article <1549@trwrb.UUCP> sansom@trwrb.UUCP (Richard Sansom) writes: > >Sorry to contribute to this silly discussion, but you knew someone was >going to rebut that last article. How did this latest bout of Amiga v.s. >ST get started anyway? >-Rich Some poor person asked for help in deciding which system to buy, sigh. Enuff... -- George Robbins - now working for, uucp: {ihnp4|seismo|rutgers}!cbmvax!grr but no way officially representing arpa: cbmvax!grr@seismo.css.GOV Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)
uh2@psuvm.bitnet.UUCP (01/25/87)
Someone asks, "I'm curious. Just how great is multi-tasking?" Now I am no wizard, but isn't the real beauty of multi-taksing a lot more than just being able to print in the background. For example, device drivers, print spoolers, communication programs, fast database systems, and a lotta other keen stuff are much easier to develop and debug if they can be implemented as a bunch of simultaneously runnig tasks on a multi-tasking machine. In other words, if 6 chimpanzees, programming at random, work on a mu;titasking system they will produce all the worlds great programs a lot faster than if they were working in MSDOS. 8-) Hey--I could be wrong.
keithd@cadovax.UUCP (01/28/87)
In article <8392@watrose.UUCP> jafischer@watrose.UUCP (Jonathan Fischer) writes: > >In article <636@mit-amt.MEDIA.MIT.EDU> ralph@ATRP.MEDIA.MIT.EDU (Amiga-Man) writes: >> ... [talks about advantages of Amiga] >>- A true multitasking OS. I find this feature very important. > > I'm really curious: just how great is multitasking? I.e., how much do >you, the typical Amiga owners, use this feature? Even on Unix I find that the >only thing I consistently use '&' for is printing, and on my ST I have a wide >range of print spoolers to choose from. I use it frequently when I'm telecommunicating. Uploading and Downloading of software is a relatively boring and time consuming event. While my terminal emulator is doing this, I'm off in another window working on something else. As long as I'm not doing down and dirty debugging of new software that is prone to crash the machine, It works pretty good, and I do this quite often. Other things that are handy, are formatting disks in background while tele- communicating, loading up ram disks, etc. I'm spoiled now, and wouldn't want to do without it. >cycle, the speed of Megamax compile-time, coupled with a RAMdisk, makes multi- >tasking a 'yeah it would be nice, but not utterly world-stopping' luxury. Well, it's not world-stopping, but I sure miss it when I'm on a machine that dosen't have it. >and is it worth the slow-down in execution? Even though I would really _like_ >it, would I really use it that much? As Matt mentioned, there is not that much slowdown, many programs spend an awful lot of time doing nothing, or waiting for something to happen, which dosen't take up any CPU at all. Keith Doyle # {ucbvax,ihnp4,decvax}!trwrb!cadovax!keithd # cadovax!keithd@ucla-locus.arpa
daveh@cbmvax.UUCP (01/29/87)
> Keywords: Mac, Amiga, ST > Xref: cbmvax comp.sys.amiga:1618 comp.sys.mac:937 comp.sys.atari.st:1063 > > > In article <636@mit-amt.MEDIA.MIT.EDU> ralph@ATRP.MEDIA.MIT.EDU (Amiga-Man) writes: >> ... [talks about advantages of Amiga] >>- A true multitasking OS. I find this feature very important. > > I'm really curious: just how great is multitasking? I.e., how much do > you, the typical Amiga owners, use this feature? Even on Unix I find that the > only thing I consistently use '&' for is printing, and on my ST I have a wide > range of print spoolers to choose from. ... > > I _DO_ envy your multitasking! I'm just curious how useful it > actually is. I.e., is it that necessary in a personal computer, > and is it worth the slow-down in execution? Even though I would really _like_ > it, would I really use it that much? > > - Jonathan Fischer Well, first of all, even if you never experience a need for multitasking, you get two things from it. First of all, the Operating System uses it. System devices, like disk driver, have a server task that operates them. The DOS will generally send messages to these tasks, which then "take it from there", often asynchronously. The nice thing about this is that a calling program isn't required to wait for the disk operation to finish before going on. Disk I/O is mostly waiting for the heads to move, so as a background task you use very little CPU time on disk access (on the Amiga, the floppy reads and writes are done by a custom chip during an interlaced DMA slot, so you have even more CPU time available. But on any machine this can be a big win). The multitasking system lets you very easily take advantage of CPU time that would otherwise be wasted in some kind of a wait loop. Another example of system multitasking is Intuition, the graphic interface manager on the Amiga. Intuition exists as a high priority background task. It monitors input events, like keyboard or mouse actions. Programs send messages to Intuition, asking for any events Intuition has noticed; Intuition tells each program about only those events its specifically concerned about. As a separate task, Intuition will never miss mouse movements or key strokes, while in a single tasking system you can very easily miss such things, or slow your program down trying not to miss any. Also, the Intuition process as a high level I/O server makes alot of sense when you consider that several different tasks may all be asking about these events. Since Intuition is there, no task need know about any other running with it. Now there's the multitasking I use myself, out of choice versus system design. Truthfully, I use multitasking on the Amiga much more than on UNIX, mainly because the windowing/screening capabilities of the Amiga let me run simultaneous interactive things much better than I can on normal UNIX (may X-Windows on a UNIX system will change this). I do the same amount of multitasking on the Apollo workstations I use here, for basically the same reasons; the windowing. To start off, I usually run a few background tasks, the print server, PopCLI (a new CLI window at the touch of a key, just like on the Apollo), and Emacs if I'm on a machine with enough memory. I can start up Kermit and download from our VAX, click that screen to the back (it keeps running, of course), and edit or compile something while the download is taking place. The ability to multitask also completely eliminates the need for specially written "desk accessory" or "RAM resident" programs, since any number of programs can run together or stick around in memory; none of them have to obey any special constraints. And the result is much greater efficiency; instead of my application program having to poll the system whenever possible to find any request for a desk accessory, my program just does what I intend to do with it. And other tasks like WorkBench or CLI can load an accessory program if I like. And finally, individual programs can benefit from multitasking. First of all, there's never any reason to kludge "DOS" type commands into a program, since you can always fire up a CLI window to do the job the right way. A program can implement things with tasks much more efficiently and effectively than with standard polling methods. One controlling task can operate with an arbitrary number of servent tasks using "software buss" messing protocols. I think most folks feel satisfied with single tasking because they've always done things that way. The more you use a system that multitasks well, like the Amiga (or an Apollo or Sun), the more you feel frustrated with the old single tasking systems. At least, that's been my experience. -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Dave Haynie {caip,ihnp4,allegra,seismo}!cbmvax!daveh "You can keep my things, they've come to take me home" -Peter Gabriel ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
braner@batcomputer.UUCP (02/02/87)
[] In the Atari ST (or the Mac, as far as I know) there is NO polling of the keyboard (nor the mouse): They are INTERRUPT-DRIVEN. Since it takes very little time to process the incoming keystrokes relative to the time in-between keystrokes, that does not degrade performance. And it has absolutely nothing to do with multi-tasking. Beyond that, the ST (or GEM, rather) has a "limited multi-tasking kernel" which lets one 'application' and several 'desk-accesories' (in other words, several programs) run simultaneously, each being reactivated when a message is addressed to it (e.g. a keystroke or a mouse click), but not bothered when not necessary. As for background reading of the disk: Usually a program NEEDS the data it requested from the disk drive BEFORE it can do anything else, so no amount of multi-tasking will speed that program up while it's waiting. On the other hand, SOME specially-designed programs sometimes read the disk BEFORE the data is needed, i.e. invite an overlap of reading the disk and some other processing. On the ST that is possible too, since the disk I/O is done via the DMA chip, which (as far as I know) CAN take a command and then execute it independently. It does steal CPU memory cycles for that, though (or does it? experts, step up?). - Moshe Braner PS: I am just trying to clarify the notion of "true multi-tasking", and NOT to continue religious wars about which machine is better.
bj@well.UUCP (02/02/87)
Multi-tasking is a super important part of the Amiga, if you care to take it as an advantage. You can have a single program commanding any number of processes and tasks to create the user inferface and magic of the program. If you want to add in sound to a program it becomes a seperate application, seperate to code and debug and use, but can coexists with the main program. If you care to you can really do a lot of stuff with the different chips and capabilities of the Amiga without slowing the main body of your program, just have different processes and/or tasks that interact using messages or signals. I come from the big computers to the Amiga, because there is SOOOOO much potential for great programs. It reguires that the developer think about different interactions between processes, but in the long run it is an advantage that can really make the Amiga a bigger success than anything else out there --- assuming that people here about the Amiga in a positive light from those that write about computers. Thank you Jerry about the Commodore blurb in InfoWorld, I also think that the "unshown machine(s)" are wonderful, if they get them all working and to the people and get the trade presses to like Commodore again. Lots to do, many hills ahead. -Jim Becker Terrapin Software