Path: utzoo!attcan!uunet!snorkelwacker!bloom-beacon!eru!hagbard!sunic!lth.se!newsuser From: d87sg@efd.lth.se (Svante Gellerstam) Newsgroups: comp.sys.amiga Subject: Re: Bank switched CHIP RAM? (Re: 24 Bit Video ..) Keywords: Off the wall idea? Message-ID: <1990Oct3.194556.7031@lth.se> Date: 3 Oct 90 19:45:56 GMT References: <1990Sep21.184056.14 <27024b15-2c05.11comp.sys.amiga-1@tronsbox.xei.com> <1990Sep28.022138.19237@zip.eecs.umich.edu> <1990Sep30.233751.3244@zorch.SF-Bay.ORG> Sender: newsuser@lth.se (LTH network news server) Reply-To: d87sg@efd.lth.se (Svante Gellerstam) Organization: Lund Institute of Technology, Sweden Lines: 56 In article <1990Sep30.233751.3244@zorch.SF-Bay.ORG> xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) writes: > > < lots of inspiering ideas on bank switched CHIPRAM deleted :-> > Ok, this is a way to get more bits per EACH color. It would not give many more colors than presently available. And there's the thing with the speed of the current chipset. Today it works just fine with our normal resolutions, but try to run the WB on a 16-color HiRes + Interlace screen on a A3000. Even on a 25MHz '030 a measly (professionally speaking) 640 x 400 screen becomes zippy as old chewinggum. The big step would be to break away from the current CHIP-mem + generic chipset architecture (not replace, just add to, that is). The really hairy problem of getting a hires display (say 1280 x 1024 x 8 plus) is mainly getting the bits onto the screen and then give the CPU or graphics coprocessor time to do its stuff. Let's assume we have a graphics adapter that can display 1280 x 1024 x (whatever) at 50 (ok 60) frames per sec. Some calculations show that we cannot meet that bandwidth even if we only allow video access to CHIP. Clearly we need some other memory running at full speed to be able to meet the screen DMA bandwidth. One hardware event that would make the bank switching idea semi-interestring is an async chipset running at lots of nice little MHz's. Then they would be able to more fully use an area of high speed video RAM. But that would also mean that every special graphics adapter would have to be specially designed for the Amiga. This implies high R&D costs and a high end price. Compatibility? Ok, as the only thing I am suggesting is a way for the system to use other video hardware transparently, the current modes and compatibility will remain 100% intact. The device.driver method seems able to accommodate all wishes graphics-wise. Just as the dos.library uses a device.driver to talk to its disk-volumes (through filesystems) the graphics.library should use a device(screen ?).driver to talk to its output device. To use the normal CHIP/generic chipset setup the driver would simply call on the current graphics.library. Existing software would just hit the firmware d:-) as usual. I'm interested in discussing details. >I know this is either three bricks shy of a load, or a little >under half baked, but what do you expect for free? All ideas has some use :-) >Kent, the man from xanth. > -- 2:200/107.4 Svante Gellerstam (Fido) d87sg@efd.lth.se (InterNet) It's the african anteater ritual! -- Can't Buy Me Love