Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!cs.utexas.edu!sun-barr!sun!pepper!cmcmanis From: cmcmanis%pepper@Sun.COM (Chuck McManis) Newsgroups: comp.sys.amiga Subject: Re: TWO Denise's?? Message-ID: <106202@sun.Eng.Sun.COM> Date: 23 May 89 00:56:43 GMT References: <2273NU140487@NDSUVM1> Sender: news@sun.Eng.Sun.COM Reply-To: cmcmanis@sun.UUCP (Chuck McManis) Organization: Sun Microsystems, Mountain View Lines: 127 In article <2273NU140487@NDSUVM1> NU140487@NDSUVM1.BITNET (Jason) writes: [ya gotta love a mainframe that insists on calling you NU140487!] > Upon reading an article appearing in the FMAUG (Fargo-Moorhead Area User >Group) newsletter... i'm just curious as to how MUCH we Amiga users are in the >dark. Upon reading this article it occured to me just how much I take my engineering degree for granted. What I find even more amazing is the _need_ some people have to believe that you can get something for nothing, and in fact their is some great conspiracy *preventing* them from getting something from nothing. Then it occurred to me that there is! Yes, it's called Physics! :-) But seriously, both the purported article that Jason read and his reaction to it are both fiction and lust respectively of the worst kind. Mainly, the unrealizable fantasy that you have your heart set on. They can't do it Jason, and if they did you couldn't afford to buy it. I know that because systems that have 1K X 1K X 8 color are available today but you don't own one because they generally cost about $10,000. There is no free lunch at all. Anyway, what follows are some comments that might let you know when you are reading something completely bogus in the future ... > The writer, who claims he had come across some material that had been >recovered from Jay Miner's "trash can", says basically that in a normal Amiga >setup, two of the Denise pins are listed as not connected. Yet they do serve >a purpose. This is great, does this guy live in Saratoga, CA? Did he mention how he got to Jay's garbage can? Why didn't he come to a FAUG meeting and talk to him directly if he was in the area ? > The original Amiga motherboard design had space for several extra sockets, >of which were 'supposed' to be OS ROMS. But Jay's material shows that this is >not the case, and that one of the sockets was to hold a second Denise chip. >The Amiga, in it's "Dual-Denise" mode, was capable of many more graphics modes. ha ha ha ha ha! Nothing personal, but first we start with an implausible fact (eg that Jay's garbage man is an Amiga newsletter author) then we extrapolate to the extreme by imagining a neat senario where there is some secret hidden capability in the Amiga. This is where I have an advantage, not only can I read a schematic, I can identify standard TTL parts when I see them. Hmmm, OS roms, hooked up to address decoders pretty sneaky that. > First off, the DD mode would have doubled the horizontal resolution by >"doubling the frequency of the dot clock and interleaving the output of each >Denise." Apparently the only reason why it was never publically made known of >was it would have required the use of a Multisync monitor (which were pretty >expensive back then). I love it. A very common technique of getting more pixels on a screen is to use shift registers on the outputs of several parallel data registers. By fetching the data in parallel you can mitigate the need for really fast access times. However, you'll notice that this doesn't say how this "other" Denise is supposed to get the data. In fact the way Denise gets the data to display is via a DMA channel in Agnus I believe feeding it to her. So sorry compardre, only one denise doesn't cut it. But wait there's more ... > In addition to doubling the horizontal resolution, a DD combo would also >allow for EXtenden HAM and EX mode. EXtended HAM would allow for HAM to be used >in hi-res mode (640X200 and 640X400)... and overscan as well. Also, instead of >a mere 16 colors, 256 colors are available. In lower resolution modes (320X200 >and 320X400) the maximum number of colors is kicked up to 16,777,216 (the >article didn't say how many were available on screen at once). There is also >a "Landscape mode", which allows for a maximum resolution of 1280X400 (plus >overscan)... which for some reason is used when the monitor is placed on it's >side. Hmmmm, So how could these two Denises communicate which pixels were in HAM mode (color gun offset) vs which were simple lookups? Answer : they couldn't. And 256 colors? If one Denise has 32 color registers, two denises have 64 color registers, how can you get 256? You can't. And how could you combine the two sets of color registers so that they were each 8 bits wide? Well you might be able to take the digital outputs and send those to a brooktree RDAC or something. But uhoh, now you can't load the color registers because there isn't any way to access the brooktree's registers. Landscape mode? > Other possiblilities were mentioned as well. Using the Denise chip in >groups of four in a "piggy-back" configuration, much like Transputer processers >are networked, another video configuration is attained. (The article failed to >go into detail about this, but said that current video technology could not >possibly accommodate these modes.) Believe me, current video technology is capable of displaying anything any number of "ganged" Denises could provide. This article reads something like a Penthouse Forum letter for a teenage hacker. "I couldn't believe it would happen to me, I found this undocumented bit and suddenly my screen had 8,000 pixels across! The system began using antialiased fonts that really got me hard ..." > Now, i'm not sure how accurate these accounts are... it's just something >that i've read like... 5 minutes ago. But knowing Jay Miner's ability >to perform miracles with stuff like this, i serioulsly wouldn't doubt it. Doubt it, you would be better off. > This also brings up the question of where Commodore is taking the Amiga. >We all know that Commodore's >ahem<... uh... "marketing" has just about >doomed the Amiga to a life of video game junkies ...etc etc... but what about >it's developers? Now I know that these guys spend a >large< portion of their >lives to give us a good and well designed machines... but apparently (upon >looking at this article, and assuming it is valid) they were not debriefed >as to what could be possible with a little creative configurations. I hope >this is the case, 'cause if they knew about it's abilities... and just said >F***-it... and went and doomed the newer machines (the A500 and the A2000) >to an inability for these configs... then i will have lost all of the respect >and admiration I hold for the developers who have taken the Amiga under their >wings. > Psst... say guys... I'd have no problem with going out and buying a >multi-sync >hint<... heck... i'd have to anyway if i wanted to use the ECS... >>nudge< ... geez, with 16,777,216 colors... i could make a heckuva neet-o >outdoor painting >wink<... :-) > Jason Well, I can assure you that Commodore isn't taking the Amiga anywhere near what you would like. And they won't either, ever. As you get some more experience under your belt you may begin to understand the limitations of current technology and what it costs to deliver that technology into a product. In the mean time, take the time to read about video, maybe check out a copy of EDN magazine and Electronic Component News. Figure out what it would take to produce the kind of display you lust after and then check the price. You will be disappointed but wiser for the effort. --Chuck McManis uucp: {anywhere}!sun!cmcmanis BIX: cmcmanis ARPAnet: cmcmanis@sun.com These opinions are my own and no one elses, but you knew that didn't you. "A most excellent barbarian ... Genghis Kahn!"