home *** CD-ROM | disk | FTP | other *** search
- From: barrett@snoopy.cs.umass.edu (Daniel Barrett)
- Newsgroups: comp.sys.amiga.hardware,comp.sys.amiga.advocacy
- Subject: The TRUTHFUL TRUTH about the TRUE A4000/AGA graphics modes
- Summary: True, all true. Mmmm, well mostly true. Sort of.
- Keywords: chimpanzee, bladder, ancient Rome
- Date: 20 Oct 92 03:35:53 GMT
-
- There has been a lot of confusion recently about the A4000, the AGA
- chipset, and interlaced (flickering) graphics. Don't worry -- help is
- here! The whole issue is really VERY SIMPLE, so I've decided to explain it
- all very simply, using very simple words, for all you very simple people.
- Simple, simple, simple. OK? So pay attention, you morons.
-
- In the beginning, there was the original graphics chipset. It
- consisted of 3 chips, called Agnostic, Dense, and Polio. Agnostic and Dense
- handled the graphics. Unfortunately, Agnostic was always doubting whether
- or not it was doing the right thing, so it would occasionally get into
- terrible arguments with Dense. As a result, the video display would
- "flicker" as the two chips fought it out.
-
- To help prevent this problem, two solutions appeared. The first was
- the MicroWay flickerFixer, a device that plugged into the A2000 video
- expansion slot. It eliminated flicker by sending huge, electronic
- shockwaves into the custom chips, frying Agnostic and Dense until they were
- forced to agree and produce a stable picture. This method of causing pain
- in electronic components is known as the "Hurt" system, and you will usually
- see a "Hurts" rating in the specifications of any display hardware. It is a
- measure of the amount of pain required to force the hardware to do what you
- want. If the hardware is particularly nasty, it needs a pain rating way up
- in the "Kill-Or-Hurt" range. But I digress.
-
- The second solution was that Commodore introduced the Enhanced Chip
- Set, or "ECS". This new chipset improved upon the original in numerous
- ways, including the ability to produce high-resolution, non-interlaced
- graphics. In order to do this, they had to ridicule the poor graphics
- chips, calling them insulting names like "Fat Agnostic" and
- "Only-Half-Bright Dense", until they agreed to work harder.
-
- Unfortunately, even Commodore's feared Department of Punishing
- Custom Chips could not force the little ECS to produce the graphics that
- some Amiga users were demanding. So, it was time to create a whole new
- chipset! One that could display 8-bit graphics, an enhanced HAM mode, and
- satisfy Amiga users everywhere! YES!! It's... THE AA CHIPSET!!!!
-
- [Excuse me? Oh! I'll tell them.]
-
- Um, the name is now officially the "AGA" (Advanced Graphic
- Architecture) chipset. Sorry about that!
-
- Anyway, the AGA chipset had the capabilities of... [What? Oh....]
- Sorry folks, but Commodore has just renamed the chipset again! It is now
- called the "RAGA" (Really Advanced Graphic Architecture) chipset.
-
- So where was I... oh yes. The RAGA chipset... [What NOW? Oh, you
- are kidding me.] Folks, you won't believe it, but Commodore has just
- changed the name of the chipset. The new and final name is the "AGAIN"
- chipset (Advanced Graphic Architecture, Infinite Names), or "AGA" for
- short. I'm glad we finally have that clear.
-
- Well, by now, I don't remember at ALL what I was talking about,
- so I'll switch topics to the Amiga 4000 and flickering graphics. Here
- is where the confusion lies. Or maybe I should say, "Here is where we
- find confusion and lies." Here are some of the current rumors:
-
- RUMOR IS IT TRUE?
- -----------------------------------------------------------------------------
- The A4000 has no flicker fixer. YES
-
- The AGA chipset always "promotes" any
- non-interlaced screen to interlaced
- mode. MAYBE
-
- The A4000 has no flicker fixer. NO
-
- Dave Haynie and Mike Sinz were found
- in an Ethopian "love nest" with 35
- rabid opossums and a jar of
- mayonnaise. E-MAIL Mr-X@blackmail.com FOR PHOTOS
-
-
- But rumors, as the saying goes, are "just rumors." Here are the VERY SIMPLE
- FACTS about interlaced video on the Amiga 4000. The following eleven steps
- will explain the TRUTH and tell you how to combat ANY video problem on this
- machine.
-
- (1) First of all, on the A4000, ALL video modes flicker. Yes, ALL of
- them -- every single one. Anybody who tells you otherwise is
- either lying or a total dweeb.
-
- (2) However, Commodore's system software "promotes" these modes to be
- non-interlaced, so you don't see the flickering. Yay!!
-
- (3) Even so, a program can SPECIFICALLY ASK to flicker, by calling
- the new OS 3.0 PleaseFlicker() function. This is the system
- friendly way to force an interlaced screen for video compatibility.
-
- (4) But the user can easily override the PleaseFlicker() function by
- using the IControl program and selecting the "Please Don't Flicker"
- gadget.
-
- (5) However, even if the user has used IControl to eliminate flicker,
- there still exists ANOTHER system function buried deep in the
- heart of the operating system. It is called ReallyFlickerAnyway()
- and it LAUGHS at the user's puny attempts to deinterlace the screen.
- This function exists not for "video compatibility", but simply to
- make life miserable for everyone.
-
- NOTE: Developers should NEVER use the ReallyFlickerAnyway()
- function unless they ABSOLUTELY MUST or if they just feel like it.
-
- (6) Happily, users can STILL get around the deadly ReallyFlickerAnyway()
- function by running any of the 3,857,294 freely distributable
- anti-flicker programs, such as Marc Barrett's "FlickerSucks"
- utility. These little programs "patch" the operating system to
- detect flickering screens and take an appropriate action. For
- example, whenever Marc's program notices that a "bad" screen will
- be opened, it cleverly displays a gigantic requester complaining
- about the flicker. (Curiously, the program doesn't FIX the screen
- -- it just complains.)
-
- In any case, there are other utilities around if Marc's doesn't fit
- your needs.
-
- (7) Unfortunately, Marc has a split personality, and his evil twin
- wrote an awful program called "The_A4000_Is_A_Kludge", which
- defeats those nice flicker-fixing utilities mentioned in step (6).
- Oh no!! And to make things worse, Marc somehow managed to get
- this program onto the A4000 Install disk so it automatically runs
- on every A4000 shipped!
-
- But don't panic -- just delete the program (it's in the WBStartup
- drawer) and your worries will go away.
-
- (8) But even now, some programs break the programming rules, bypass the
- Amiga operating system, and go straight to the hardware, stuffing
- values directly into the GR_FLKR register and causing the fatal
- flicker. Once again, your little anti-flicker utilities can't help.
-
- (9) To solve the problem of these hardware-banging programs, simply buy
- a Commodore A2320 or other deinterlacer and install it in the A4000
- processor slot or joystick port or wherever the hell it goes. Now,
- even those illegally-programmed games and demos will look wonderful.
-
- (10) However, some A4000 video modes have too many bitplanes to work with
- the A2320, so these can't be deinterlaced so easily. Oh no! Can
- anything be done about this??
-
- (11) Don't worry! As stated above, Commodore's system software promotes
- these modes to be non-interlaced. Go to step (3).
-
- So, there you have the complete information! These steps should
- explain EVERYTHING you need to know about the Amiga 4000 and flickering
- screens. If you have any further questions, please post them in alt.flicker
- or rec.arts.birdpoop because you are obviously very stupid, and even I
- can't help you.
-
- Dan
-
- //////////////////////////////////////\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
- | Dan Barrett -- Dept of Computer Science, Lederle Graduate Research Center |
- | University of Massachusetts, Amherst, MA 01003 -- barrett@cs.umass.edu |
- \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\/////////////////////////////////////
- ---
- Copyright 1992 by Daniel J. Barrett. All rights reserved.
- This article may be freely distributed as long as it is distributed in its
- entirety. It may not be included in any publication without the written
- permission of the author. So nyaaah.
-