melling@cs.psu.edu (Michael D Mellinger) (05/06/91)
Here is an article that someone from NeXT posted last month in response to some questions about the NeXTstation color. The only animation that I have seen on the NeXT has been small images, so I don't know how fast the NeXT really is. The #'s quoted here are *quite large* and I'm not sure I will believe them until I see some better animation with my own eyes. -Mike =========================================================================== From: aozer@next.com (Ali Ozer) Subject: Re: ColorStation questions Date: 24 Apr 91 23:21:51 GMT In article <1991Apr24.082948.17763@cs.ucla.edu> George Wu writes: >I am thinking about buying a color NextStation but I have been >somewhat alerted by some recent rumors about its capabilities. > It is known that the color NextStation can display 4096 colors > simultaneously using 4-bits per pixel for R,G, and B. Someone > thought this meant only 16 gray levels can be displayed ever ! Is > this true ? Yes, it is, of the 4096 different color values each pixel can take on, 16 of them are pure gray (Red == Green == Blue). However, PostScript employs dithering to display a lot more colors than can be represented by the device pixel values; thus a 256-gray image will look a lot better on the NeXTstation Color than on a non-dithered 16-bit display device. In many cases a 24-bit color image on the NeXTstation Color display is hard to distinguish from the same image on a 24-bit display. > Someone said the color NextStation display is 3-4 times slower > than the monochrome NextStation. Does this mean real-time > animation is impossible to do on the color NextStation ? It all depends on what you do, but my experience is that "3-4 times slower" is not the general case. Fiddling with the various user interface objects, typing, scrolling, searching, compiling, debugging, etc are all zippy; the color machine feels as fast as the NeXTstation in most cases. The few times when the NeXTstation Color will feel slower than the monochrome machine is when an app is trying to open a big window with color in it; a document-sized color window occupies about one meg, and trying to allocate that memory will probably cause some paging and disk activity at first. However, once the window is up and is in use, drawing, scrolling, moving, etc are all real fast. Certainly not 3-4 times slower. Thus the biggest hit you take is because of the increased memory usage of apps with color windows. As mentioned above, a document sized color window occupies about 1M of backing store, and with several such windows in different apps, trying to switch between them might cause some paging. However, thanks to the window server's automatic depth promotion strategy, which allows windows to get deeper as they need to, a lot of the windows on the NeXTstation Color actually use the same amount of memory as those on the monochrome machine. Your vanilla Edit & Terminal windows, as well as your Workspace browsers or Mail windows which haven't displayed any color, all occupy as much memory as their monochrome counterparts. Also, thanks the optimizations in the window server and NeXTstation Color's improved memory bandwidth, added to the fact that PostScript drawing is a lot more than just putting pixels down, the raw drawing speed is not much slower in the color case either. For instance, drawing a rather complicated PostScript image ("Cobra" by Keith Ohlfs) into a color window takes about the same time drawing it into a monochrome one (36 seconds). (It used to take about 32 minutes to print the file on a LaserWriter Plus!) Another case is running BreakApp (from /NextDeveloper/Demos) with a screen-sized window. It runs at about 70-75 frames/second on the NeXTstation, and at about 35-40 frames/second on the NeXTstation Color. With a monochrome image, the frame rate goes up to 80-85 frames/second on the color machine. With the default sized window, the frame rate is 105 on *both* the NeXTstation and the NeXTstation Color, and 130 with a monochrome image on the NeXTstation Color. (These are all highly informal timings by the way, I just did them while typing this message up. Not official benchmarks by any means!) Anyway, my experience has been that during every day, steady state usage the NeXTstation Color is certainly not 3-4 times slower than the NeXTstation; for most things, it's as fast. Ali, Ali_Ozer@NeXT.com
bard@jessica.stanford.edu (David Hopper) (05/06/91)
In article <3gbG4*$*1@cs.psu.edu> melling@cs.psu.edu (Michael D Mellinger) writes: > >don't know how fast the NeXT really is. The #'s quoted here are >*quite large* and I'm not sure I will believe them until I see some >better animation with my own eyes. Nor I. Thanks for the skepticism, Mike. >-Mike > >=========================================================================== >From: aozer@next.com (Ali Ozer) Poor Ali. He was an Amiga-ite before he was brainwashed by Jobs. (Wotta hypocrite I yam ;-). >It all depends on what you do, but my experience is that "3-4 times slower" >is not the general case. Well, MY experience is that 3-4 times slower IS the general case. Only rarely is it NOT that slow. >Fiddling with the various user interface objects, typing, scrolling, >searching, compiling, debugging, etc are all zippy; the color machine feels >as fast as the NeXTstation in most cases. The few times when the >[...] >at first. However, once the window is up and is in use, drawing, >scrolling, moving, etc are all real fast. Certainly not 3-4 times slower. Well, of course this will depend on the configuration. I've used a NeXTstation Color, and it was slower in practice (although it WAS faster than my '030). >(from /NextDeveloper/Demos) with a screen-sized window. It runs at about >70-75 frames/second on the NeXTstation, and at about 35-40 frames/second >on the NeXTstation Color. With a monochrome image, the frame rate >goes up to 80-85 frames/second on the color machine. With the default sized >window, the frame rate is 105 on *both* the NeXTstation and the >NeXTstation Color, and 130 with a monochrome image on the NeXTstation >Color. (These are all highly informal timings by the way, I just did >them while typing this message up. Not official benchmarks by any >means!) Not official? These are ridiculous. I wonder what he used to do the timing. Try animating something large, even on an '040. You can SEE the frame rate, meaning it's at best well below 30fps. It's jerky, as well. If an object is partly off-screen, it will visibly speed up; it's also clear that maintaining a high frame rate consistently is impossible. Even BreakApp gets jerky. Welcome to Mach, folks. >Anyway, my experience has been that during every day, steady state usage the >NeXTstation Color is certainly not 3-4 times slower than the NeXTstation; >for most things, it's as fast. > >Ali, Ali_Ozer@NeXT.com I think it's pretty much understood that the NeXT has not the real-time OS that the Amiga has. If the state of animation on the NeXT is exemplified by the movies and games provided on-disk (c'mon, it's been two years now), then the NeXT is no competition when it comes to animation. Even if Ali seems to think it is ;-) Dave Hopper | /// Anthro Creep | Academic Info Resources, Stanford |__ /// . . | Macincrap/UNIX Consultant bard@jessica. |\\\/// Ia! Ia! | -- Just remember: love is life, and Stanford.EDU | \XX/ Shub-Niggurath! | hate is living death. :Black Sabbath
aozer@next.com (Ali Ozer) (05/08/91)
In article <1991May6.024252.12256@leland.Stanford.EDU> David Hopper writes: >In article <3gbG4*$*1@cs.psu.edu> Michael D Mellinger writes: >>don't know how fast the NeXT really is. The #'s quoted here are >>*quite large* and I'm not sure I will believe them until I see some >>better animation with my own eyes. >Nor I. Thanks for the skepticism, Mike. >>From: aozer@next.com (Ali Ozer) >>(from /NextDeveloper/Demos) with a screen-sized window. It runs at about >>70-75 frames/second on the NeXTstation, and at about 35-40 frames/second >>on the NeXTstation Color. With a monochrome image, the frame rate >>goes up to 80-85 frames/second on the color machine. With the default sized >>window, the frame rate is 105 on *both* the NeXTstation and the >>NeXTstation Color, and 130 with a monochrome image on the NeXTstation >>Color. (These are all highly informal timings by the way, I just did >>them while typing this message up. Not official benchmarks by any >>means!) >Not official? These are ridiculous. I wonder what he used to do the >timing. A time function at the top of the animation loop was what I used; the source is on the machine, you can try it yourself. This app uses compositing, which is fast, and it composites sections which are not the size of the whole screen. Thus these values are correct and repeatable. You can even use something like the following to time compositing --- the below code composites a 400 x 400 dark gray area, and takes 3ms doing it. With 12-bit color, it takes 16 ms/frame. With these values in mind, I hope you can see that the numbers I quoted above are perfectly reasonable. /g gstate def 0 0 400 400 0.333 setgray rectfill 500 {0 0 400 400 g 400 400 Copy composite} repeat Ali