Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!uwvax!puff!upl From: upl@puff.WISC.EDU (Future Unix Gurus) Newsgroups: comp.graphics Subject: Re: Amiga World Ray-tracing article... Message-ID: <677@puff.WISC.EDU> Date: Mon, 20-Apr-87 11:45:14 EST Article-I.D.: puff.677 Posted: Mon Apr 20 11:45:14 1987 Date-Received: Tue, 21-Apr-87 01:07:05 EST References: <629@puff.WISC.EDU$ <2985@sdcsvax.UCSD.EDU$ <647@puff.WISC.EDU$ <239@rocky.STANFORD.EDU$ <4612@utcsri.UUCP$ <854@xanth.UUCP$ Reply-To: upl@puff.WISC.EDU (Future Unix Gurus) Distribution: comp Organization: U of Wisconsin CS Dept Lines: 112 Keywords: cost In article <854@xanth.UUCP$ kent@xanth.UUCP (Kent Paul Dolan) writes: $In article <4612@utcsri.UUCP$ buchanan@utcsri.UUCP (John Buchanan) writes: $$In article <239@rocky.STANFORD.EDU$ ali@rocky.UUCP (Ali Ozer) writes: $$$still use my Amiga. And thanks to multitasking you do not need to sit and $$$watch your Amiga grind away on ray-traced images. Besides, the $$ $$Hmmm Last starfighter ship = 250000 polygons. $$ Amiga memory = 512000 bytes $$ 2 bytes per polygon = 500000 bytes. ( it seems that under estimating $$ is the name of the game.) $$ =============== $$ Memory available for $$ raytracer. = 12000 bytes. $$ $$ $$ I fail to see where the multitasking system will reside. I'd also $$ like to see at least 24 bits per pixel. $ $Whoa! $ $The original Amiga 1000 came with 256K bytes of memory, and there was an easy $add on for another 256K bytes. (There was also always a "hidden" 256K bytes $where the operating system ("Kickstart") was loaded.) However, the available $users memory address space included another 8M bytes of memory, making the $original machine an 8.5M byte machine, not a 0.5M byte machine. $ Sure, if you add another $500+ for the expansion box. (I have one on my machine, and love it, but buying it really hurt.) The 2000, which can be expanded internally, with no extra hardware (outside of chips) to 1 meg I considerr a base 1 meg machine. The 1000 is a base .5 meg machine since it needs major extra hardware to bring it any higher. After all, for $500 you can get a card with a couple of meg for the IBMPC - does that make it a multi-meg machine??? Or perhapse more to the point, you can buy an extra card-cage for the IBM, does that make it a base machine with twice as many slots? $Since then, Commodore has relinquished claim to another megabyte of memory (of $the total 16M bytes provided by 24 bit addressing), permitting it also to be $used for user expansion memory. This makes the Amiga a 9.5M byte machine $from the user's point of view, today. This is a linear address space, a $big improvement over the Baby Blue clones' segmented memory. But does this old reserved space autoconfig??? (This is a question, I don't know the answer.) $There are lots of third party vendors providing add on memory units from 0.5 $to 8.0 meg for the Amiga. I run a 2.5M byte system at home, and I have yet $to run out of memory, even after copying a couple of the 880Kbyte floppies $into ram disk to save disk access time. Then again, you aren't doing professional quality ray-tracing, are you??? We are talking a REAL memory intensive application here. $ $As to the 24 bit frame buffer, I'd like one too, and someday I expect to add $one as a peripheral. There is no way I want to pay for a home computer with $the memory bandwidth to support that from memory to video display, though, at $the price of today's fast memory. The Amiga in HAM mode (see other articles) $can display pictures with near photographic realism. More would be nice, but $more would always be nice; it just takes paying for. I'm in agreeement here. HAM mode is fine for me, from a micro. $ $On multitasking: this evening, for a lark, I put up 39 demos with graphics $output, all on the screen, all running at once, and all obviously doing $something. The windows in which they ran were overlapped, nested, a real $mess, and yet the Amiga kept up. With this much junk around, moving a window $was worth a 20 second pause, but this isn't a realistic way to use the $machine. Neither is ray-tracing. The point you have missed here is all your demos are custom-chip (blitter etc) intensive. Ray tracing can use almost none of the abilities of the custom chips. It is a compute-intensive application that requires tons of processor time. $ $Practically, like the previous author, I have found myself printing one file, $downloading another with kermit, unpacking a third with arc, and editing a $fourth with micro-emacs, all at once. This is useful, and it does work. $Since all but the arc process (which I usually run memory to memory) are I/O $limited, the editing procedes at a comfortable pace, even with everything $else going on. It isn't a Cray X/MP, and there is an occassional pause, $but that is a small price to pay to get away from serial processing. $ $I'm hardly disinterested; I liked the computer so much I went back and $bought some of the stock. Gambler, aren't you? If it pays off, it should pay off nicely.. if not... $However, lack of care by publishers of Amiga $reviews leave the Amiga with the reputation of being a slow, half megabyte $machine. The floppy disk access is slow, but multi-megabyte memory is $possible, and, with add on enough memory to dump the contents of a floppy into $ram disk (a ram disk driver is standard as part of AmigaDOS), the machine is $screamingly swift. For a graphics type like myself, with it's special $purpose graphics coprocesser chips, the Amiga is unexcelled anywhere near $it's price, and, except for the resolution/pixel depth limitations of slower $memory, exceeds the performance of machines for which I paid $50,000 a decade $ago. I agree with all this. Thats why I bought one (and put my self in debt for 2 years...). In the name of "perspective", the original point of all this has gotten lost. Since I started this holy-war (which IS what it has become), I feel somewhat obligated to try to bring it back there. The point was NOT that an Amiga isn't a cray, NOT that the Amiga is not a wonderful and inexpensive graphics box, BUT that ray tracing as a movie making procedure on the Amiga is silly and stupid. You WASTE everything that makes the Amiga what it is, except the screen. And if you are just gonna use it as a display tube, do your work on a bigger machine and download. No matter HOW MUCH you love your Amiga, an hour/frame just wont cut it for film work. Jeff Kesselman uhura!captain@puff.cs.wisc.edu