Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!pikes!slate!mfriedel From: mfriedel@slate.mines.colorado.edu (Fried Mike Microwave) Newsgroups: comp.sys.next Subject: Color Station questions Keywords: Memory,X,display Message-ID: <1991Apr15.045150.39403@slate.mines.colorado.edu> Date: 15 Apr 91 04:51:50 GMT Sender: mfriedel@slate.mines.colorado.edu (Fried Mike Microwave) Organization: Colorado School of Mines Lines: 108 I have recently seen a lot of questions about the NeXTstation color. Here are a few answers I can supply. 1) Speed of Display The display is faster than a '30 cube. Depending on the number of open windows and their respective bit-levels. (Yes it makes a difference). As most applications come up in gray-scale (2bit) by default the display is almost as fast as monochrome 0'40. Yes it is possible to make the display dog-slow, but only if the the windowsizes exceed the available RAM (and the swapper gets more than its fair share), and that takes BIG windows and a lot of them. But this is true for all color displays. So as usual more memory helps. (20 is a reasonable value). 2) Number of available colors 4096 colors can be displayed at once on the screen out of a set of 16million. John Graves from NeXT wrote to me: >Each pixel on NeXTstation Color is represented by 16 bits in DRAM, four bits >each for red, green, and blue, plus four bits of "alpha" for transparency. In >VRAM (video ram), each pixel is represented by12 bits, four each for red, >green, and blue. Overlaping images are "composited" by the PostScript window >manager, taking account of their transparency, before they are put into VRAM. >Try dragging around an icon for a WriteNow document or use Molecule.App (if you>have an extended system) to see the effects of transparency. >The RAMDAC receives four bits from the VRAMs for each color (red, green, and >blue). These four bits address a color palette RAM inside the RAMDAC, >selecting an eight bit DAC value. The color palette is set by the window >manager (PostScript) based on the brightness control and a gamma correction >function to get the best set of sixteen intensities from the available 256 for >each channel of red, green, and blue. The gamma function is used to compensate>for the non-linearity of the phosphors in the monitor. The color palette is >not accessible to the user, to prevent one application from messing us the >color palette for all applications. 3) X in color. Yes it is available. I have ported it (from Mouse-X) and people who want to test it are welcome to try. It has a few minor bugs left. Most applications run fine, only applications that can't deal with TrueColor (that is the only implemented visual for the moment). I am planning to implement other visuals, like Direct Color, but I need some more hardware specifactions first, and more time. 4) Developing color apps No, you don't need a color station, or a NeXtdimension to develop color apps. Here is an excerpt from the Release Notes. > 7 Multiple, Uniform Window Depths >With support for multiple screens comes the need for windows to represent >data in varying depths. NeXT has defined in nextdict four standard depths that>windows may logically represent: > > NX_TwoBitGray (1 spp, 2 bps, 2 bpp, planar) > NX_EightBitGray (1 spp, 8 bps, 8 bpp, planar) > NX_TwelveBitRGB (3 spp, 4 bps, 16 bpp, interleaved) > NX_TwentyFourBitRGB (3 spp, 8 bps, 32 bpp, interleaved) > > >In addition, NX_DefaultDepth is defined as the default depth limit in the >Window Server's current context. Default depth limits are described below. > >A window's depth is uniform throughout its bounds no matter where it lies in >the workspace. This means one can open a 32-bit color window on a MegaPixel >display even though the full depth and color cannot be seen. This is extremely>useful for painting and image-processing applications. Our strategy is a >memory-saving, information-preserving one: Most users or developers shouldn't >worry about window depths since they are handled automatically by the Window >Server and Application Kit. However, if a developer wishes to control window >depths more directly, we have defined a simple API for this control. > > We introduce the concept of lazy depth promotion. Windows start out at >minimal depth, for example, NX_TwoBitGray, and are automatically promoted to a >higher depth when necessary. When one draws precise gray or color into a >window, the Window Server may promote it to a higher depth that will better >represent the new data. What depth the window promotes to depends on the color>or image being rendered and the window's depth limit. > >A window's depth limit is the maximum depth a window may attain. It is set >implicitly during window creation to its context's default depth limit. The >Window Server assigns each new context a default depth limit equal to the >maximum depth visible on the system. For example, if you have a 32-bit color >display and a MegaPixel display, the default depth limit would be set to >NX_TwentyFourBitRGB. If you only had a MegaPixel display, the default depth >limit would be set to NX_TwoBitGray. The context's default depth limit can be >changed with the setdefaultdepthlimit operator. An individual window's depth >limit can be changed via the setwindowdepthlimit operator. WARNING: The >Application Kit controls the depth limits of its contexts and windows. You can>also find out what a window's current logical depth is by calling >currentwindowdepth. >A promotion example: If a window is NX_TwoBitGray and it's depth limit is >NX_TwelveBitRGB, and you draw color, the window will automatically be promoted >to NX_TwelveBitRGB before rendering. Lazy promotion is also triggered by the >precision of alpha you render with. > 5) The monitor (17 inch that is) Yes, one can notice the difference between the monochrome monitor and the colormonitor. On the color monitor single pixel black lines on the borders diverge a little. Text is just as crisp as on the monochrome monitor though. 6) Memory The ColorStation does not use the same chips as the other slabs. It needs 80ns 72 pin SIMMS. (1 or 4meg, single sided only). Memory is added o in banks of two. On a 12meg slab it has two 4Meg and four 1Meg installed leaving 2 slots empty. It also has another slot to add extra memory for the DSP chip. (one 64pin socket). I like my color station, I think it is a great buy for the $$$. Not really compareable to anything else out there. The performance is generally more than pleasing. And Mathematica and color (even animated is just amazing). Hope this helps Michael Friedel (mfriedel@basalt.Mines.Colorado.EDU) -- /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ No user serviceable part inside. Warranty void if opend modified or tampered with. No batteries included.