portuesi@tweezers.esd.sgi.com (Michael Portuesi) (01/05/90)
>>>>> On 5 Jan 90 16:59:39 GMT, matthews@eleazar.dartmouth.edu (Jim Matthews) said: jim> In article <1086@crash.cts.com> uzun@pnet01.cts.com (Roger Uzun) writes: > You CAN do this on the Amiga no >problem, what you cannot do on the Mac II is create custom screens with >your preferred resolution (up to about 710X490). For the programmer, the >amigas way of doing this is MUCH more flexible. jim> This flexibility violates the spirit of a multitasking OS. A program jim> shouldn't be able to unilaterally modify the appearance of another jim> program's window. Allowing programs to change resolution or screen jim> depth means that they can monopolize a shared resource, namely the jim> screen. On the Amiga, application programs do not change resolution or depth of the display. Rather, they request their own "virtual screen" with a custom color palette, display depth, mode settings, etc. Intuition (the Amiga windowing interface) manages each one of these virtual screens separately, and allows the user to move and stack them on the physical screen in real time, much like sliding chalkboards in a lecture hall. The end result is that each application gets the screen display they want to have without disturbing other concurrent applications, which is in the spirit of a multitasking OS. This is not meant to be a "my computer is better than your computer" flame. It is meant solely to correct misinformation. --M -- __ \/ Michael Portuesi Silicon Graphics Computer Systems, Inc. portuesi@SGI.COM Entry Systems Division -- Engineering
matthews@eleazar.dartmouth.edu (Jim Matthews) (01/06/90)
In article <1086@crash.cts.com> uzun@pnet01.cts.com (Roger Uzun) writes: > You CAN do this on the Amiga no >problem, what you cannot do on the Mac II is create custom screens with >your preferred resolution (up to about 710X490). For the programmer, the >amigas way of doing this is MUCH more flexible. This flexibility violates the spirit of a multitasking OS. A program shouldn't be able to unilaterally modify the appearance of another program's window. Allowing programs to change resolution or screen depth means that they can monopolize a shared resource, namely the screen. The Mac has one problem in this regard, in that programs can change the color palette for a screen. This problem will disappear when true color is affordable and fast enough for programs to dispense with color lookup tables. Jim Matthews Dartmouth Software Development
new@udel.edu (Darren New) (01/06/90)
In article <18316@dartvax.Dartmouth.EDU> matthews@eleazar.dartmouth.edu (Jim Matthews) writes: >>stuff about amiga screen resolutions more flexable than the Mac's >This flexibility violates the spirit of a multitasking OS. A program >shouldn't be able to unilaterally modify the appearance of another >program's window. Allowing programs to change resolution or screen >depth means that they can monopolize a shared resource, namely the >screen. >... >Jim Matthews >Dartmouth Software Development Say what? Methinks you have not used an Amiga much... (no offense). Programs that want to change the resolution and colors they use generally open a new (virtual) screen, not modify an already-existant screen. There is a standard (virtual) screen (the "workbench" screen) which applications normally share and which some hacks modify the parameters of in a usually-invisible way. But programs which want something other than the standard workbench screen (like paint programs, say) normally open their own screen which can appear in front of, in back of, or along with the workbench screen at the user's discretion. Saying that the Amiga programs which change resolution "monopolize" a shared resource is like saying that a Mac program can "monopolize" the screen by openning a window that overlaps other windows. I would not call either of these situations "monolopize" because the user has complete control in both cases of what is seen. Normally, programs that open "custom" screens are usually the only programs to open windows on that screen, whereas the "workbench" screen (and maybe others in the future) are shared by all. -- Darren (Notice that bashing something into the ground can get you around the INews include limit? :-)
daveh@cbmvax.commodore.com (Dave Haynie) (01/06/90)
in article <18316@dartvax.Dartmouth.EDU>, matthews@eleazar.dartmouth.edu (Jim Matthews) says: > Xref: cbmvax comp.sys.amiga:49325 comp.sys.mac:48949 > In article <1086@crash.cts.com> uzun@pnet01.cts.com (Roger Uzun) writes: >> You CAN do this on the Amiga no problem, what you cannot do on the Mac II >>is create custom screens with your preferred resolution (up to about 710X490). > This flexibility violates the spirit of a multitasking OS. A program > shouldn't be able to unilaterally modify the appearance of another > program's window. Allowing programs to change resolution or screen > depth means that they can monopolize a shared resource, namely the > screen. But that's why you have custom screens on an Amiga. No one (at least, no one who's well behaved) modifies the color or resolution of the Workbench screen (eg, the default screen) except perhaps the User, via a preferences program. Applications that decide they need a particular set of color|resolution that is different that the default can freely open it's own custom screen. This screen is not a public, shared resource, but something private to that application, and in no way violates the spirit of multitasking. > The Mac has one problem in this regard, in that programs can change the > color palette for a screen. And the user can't! I've been trying to get the durn Mac II cx in our lab to display my choice of colors on the 2 color screen, rather than the black and white that Apple has apparently decreed are My Preferred Colors. > Jim Matthews > Dartmouth Software Development -- Dave Haynie Commodore-Amiga (Systems Engineering) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy Too much of everything is just enough
sho@maxwell.physics.purdue.edu (Sho Kuwamoto) (01/06/90)
In article <18316@dartvax.Dartmouth.EDU> matthews@eleazar.dartmouth.edu (Jim Matthews) writes: >The Mac has one problem in this regard, in that programs can change the >color palette for a screen. This problem will disappear when true >color is affordable and fast enough for programs to dispense with color >lookup tables. Is this how it works on today's 24bit boards? What if you want to cycle colors, or use the lookup tables for animation? -Sho -- sho@physics.purdue.edu
uzun@pnet01.cts.com (Roger Uzun) (01/06/90)
>> This flexibility violates the spirit of a multitasking OS
You seem to have misunderstood the concept of virtual screens,
An application sets up the screen size, resolution, depth as
it sees fit, and many give a number of choices, there are MANY
screens available at any time, the can be depth arranged and can have
windows attached. It DOES NOT violate the spirit of multitasking,
indeed the amiga is a TRUE multitasking machine and the screen
is a resource, that is virtual screens are. One program cannot
legally affect the aspects of anothers screens.
Having worked extensively with MultiFinder and AMigas OS,
I much prefer the Amiga approach, most who have tried both
also prefer this aspect of the Amiga exec.
-Roger
UUCP: {hplabs!hp-sdd ucsd nosc}!crash!pnet01!uzun
ARPA: crash!pnet01!uzun@nosc.mil
INET: uzun@pnet01.cts.comUH2@PSUVM.BITNET (Lee Sailer) (01/06/90)
In article <18316@dartvax.Dartmouth.EDU>, matthews@eleazar.dartmouth.edu (Jim Matthews) says: > >This flexibility violates the spirit of a multitasking OS. A program >shouldn't be able to unilaterally modify the appearance of another >program's window. Allowing programs to change resolution or screen >depth means that they can monopolize a shared resource, namely the I disagree. I think perhaps you are confusing "multi-tasking" with "multi-user." I probably don't want another user to modify my windows and screens, but there are many cases where I want to run program A, and then run program B to change the appearance of program A's window or screen. I might change its size, color, font, or position in some way that the author of program A did not anticipate. lee >screen. > >The Mac has one problem in this regard, in that programs can change the >color palette for a screen. This problem will disappear when true >color is affordable and fast enough for programs to dispense with color >lookup tables. > >Jim Matthews >Dartmouth Software Development
krag@cup.portal.com (Kevin Ray Grotjohn) (01/07/90)
>Drivel about wierd screen widths violating the spirit of a multitasking os. >Also about how the MAC has a slight problem with color pallettes when running >multiple programs. The amiga has slidable screens that can have different resolutions and color palletes and depth. This avoids the problem entirely. You can have an editor on a 1 bit screen for performance while running a 4096 color paint program on another screen. Look at the Amiga WorkBench sometime, notice the gadgets in the corner? Those are screen front/back gadgets. I'd hate to use a wordprocessor on a "True color" 32bit deep screen.