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Wrap

Text File | 2002-01-12 | 15.7 KB | 300 lines

<head> <title="...forever..."> <font=monaco10.fnt> <image=back.raw w=256 h=256 t=-1> <buf=4550> <bgcolor=-1> <background=0> <link_color=128> <module=console.mod> <pal=back.pal> colors: 251 - black </head> <body> <frame x=35 y=0 w=640 h=1400 b=-1 c=-1> <f0><c253> :::::::::::::::::::::::: ._______. _____ ::___. ______ ______ ._____.___ .__| ____| / \ :| | / /_ / /\ |__ \ / | |_______| /___ \:|___|___.(_____( ( (_____/ ) / \ \/ |______| /__\____\: |_____| \______\ \_____/ /___\___\ :: ::::::::::::::::::::::::::::::::::::::::::::: The Falcon Demo scene ... FPU or not ? 4 or 14 MB ? Accelerator needed ? In the previous days, the discussion about wether Atari Falcon demos should support, favour or require accelerators, an FPU for quick floating point mathematics or more than 4 MB RAM has reached new heights. Despite the excellent demo releases from the Error In Line 2001, people still argue about wether it is legal to use an FPU, an accelerator or more than 4 MB RAM. This discussion is probably much easier to deal with if some background information is given which i will try to provide with this small article. First, let's have some history. The Falcon030 was originally named Sparrow and was supposed to be a sequel to the 1040 STE as well as the "smallest" computer of a whole new series of homecomputers that were capable of dealing with what was just coming up these days: Multimedia. Orginally, this Sparrow had an 68000 CPU and NOT an 68030. Since the system was planned to be as much 1040 STE compatible as the extended capabilities, graphic- and soundwise, allowed, an 68000 processor was a necessity. But obviously, Atari decided to go for an 68030 instead. Either they got afraid of the competition namely the Commodore Amiga that was perfectly handling multimedia applications for more than 4 years at that time, or they feared to be laughed at when presenting another 68000 system just as Intel presented 486 machines - we don't know. The system got named Falcon030 instead of Sparrow, it was given an 68030 and did not get a chip named "Rascal" that was supposed to be the sequel of the Microwire interface of the 1040 STE and serve similar purposes, this time only for 16 bit DMA stereo 8-channel sound. Atari decided to give this computer an 68030, but they did not tell the bus about this change. The whole bus-design within the Atari Falcon was originally intended to carry an 68000 and not an 68030 - The difference is obvious: While the 68000 is a 16-bit processor and only works internally on a 32-bit basis, the 68030 (that has been used by SUN and Hewlett-Packard for servers and workstations for some time) is a real 32-bit processor. Atari kind of patched this problem so that the 68030 access the DRAM with 32-bit - but no other device in the Atari Falcon operates in 32 bit. Now this makes a few things obvious. First it describes pretty well why the Falcon has a Blitter which the TT does not - even though the 68030 copies data a lot faster around in memory usually than the Blitter does. It explains why there is no FastRAM which the TT gained a lot of speed from. It gives a hint why the Falcon was sold in that 1040 ST case with the miserable keyboard and why some subsystems of the Falcon, for example the SCSI subsystem, is relatively slow. The Falcon030 was still intended to be the smallest one of a new generation of computers, yet we all know that Atari never released any other ones making the Falcon the ONLY computer of the new series. This story has a morale and i'd like to point it out: The Falcon was never supposed to be incredibly fast. It never was intended to feature a powerful CPU, lots of memory or other gadgets a lot of people would have enjoyed. In other words: The Falcon030 was never supposed to compete with high-paced PCs of 66 MHz and above, it never was intended to compete with an Amiga 4000 or the even the TT. And that kind of sets the limits for this machine. On the other hand, Atari obviously never enabled a lof of features that the design of the Falcon030 allowed. For example, they did give it an FPU slot - but never shipped it with FPU included, even though TT software started to use the FPU slowly, but surely. And even though the Falcon030 had an 68030 like the TT had, Atari obviously never aimed the Falcon030 to attract TT-users to buy a Falcon. Atari only gave it a minimum set of possible resolutions, even though they gave the Videl, the graphics chip of the Falcon, a lot more possibilities - The highest resolution featured by standard GEM on RGB is 640 x 400 interlaced even though Atari included an overscan bit that allows resolutions of 768 x 512. Atari neither gave it FastRAM which would have been easy with an 68030 and did not overclock the CPU - which was exactly what they had done in the TT to gain more speed. After all, the TT too was designed as a 16 MHz machine and was shipped with a 32 MHz CPU on a 16 MHz bus. Of course, third party developers immediatelly jumped on these possibilites to explore them. Major Atari retailers sold the Falcon after a while only with a built-in resolution enhancer and not to mention that ScreenBlaster and BlowUp got more or less standard Add-Ons for every Falcon owner immediatelly - These low-cost extensions only used the possibilities Atari had given the Falcon. After a few weeks more, major Atari dealers only sold the Falcon with a built-in CPU doubler since this was so easy to do with the 68030 - Even though this did not increase the Falcon's speed a lot due to the lack of FastRAM. Speaking of FastRAM - That was available quite soon as well. Extension cards giving the Falcon either 4 or 8 MB FastRAM plus the original 4 MB ST RAM gave an additional speed up for applications that were capable of using it since the FastRAM can only be accessed by the CPU. And finally, if you wanted to have everything at once, you could buy a BlowUp FX card that enhanced the resolutions, featured FastRAM and double-clocked the CPU, making more or less a TT out of the Falcon. It even offered to overclock the bus - unfortunately, not very reliably. Didn't i start this article about 14 MB and accelerator-friendly demos ? How does the paragraph above about all the Falcon extensions mix with the purpose of this article ? This is quite simple: I wanted to point out that the Falcon is a machine with a lot of unused potential so what some people might call "cheating" by using FPUs, FastRAM or overclocked CPUs can in fact be seen as using the resources the Falcon030 has but Atari decided not to explore themselves. Nonsense, you might say, the Falcon has been sold with 4 MB, a 65 MB harddisk and a 16 MHz CPU and a 16 MHz Bus so that's what demos are supposed to use. This is not quite correct. The Falcon was as well sold with 1 MB and yet hardly any demo runs on that machine. The Falcon was also available with 14 MB by Atari even though this configuration was extremely expensive. So 14 MB is not really non-standard. Then about the FPU - Atari gave the Falcon a socket, so why is an unused socket standard and putting a chip in it and using this chip isn't ? Doesn't that kind of sound irrational, declaring an empty slot to be standard ? And about accelerators - Atari decided to have the CPU run in slow-mode in the Falcon but a lof of people bought their Falcon by retailers that automatically sold it with a clock-doubler to have a 32 MHz CPU. So why not use what the machine offers in the first place ? If people considering non-FPU, 4 MB, 16 MHz as the standard because Atari sold the majority of Falcons that way, they should run their Falcons in 640 x 400 on RGB and in 320 x 480 True Colour on VGA and dump their Screenblasters and BlowUp cards because Atari only sold the Falcon with the limited graphic abilities offered by the GEMDOS resolution switcher. Okay, let's approach this from another angle. Why do the demos or rather demo-programmers see the need for using the FPU, more than 4 MB RAM or accelerators anyway ? First, let's argue about the RAM used and let's get one thing straight right away: The RAM hardly limits the effects of a demo - code never uses a lot of memory. However, large hires graphics, multichannel mods and these things take up a lot of RAM. So when programming for 4 MB you either have to limit yourself about the use of graphics and music, you have to do without a lot of bitmaps and textures or you simply have to load a lot in between. Using 14 MB simply makes things easier. You can have an mp2 in RAM and play it from there. And mind you, mp2 hardly needs any CPU time and is therefore preferred by some programmers. You can have a lot of variation of textures and bitmaps in one effect without having to load them from disk each time you want to use them. Basically, every effect that can be written for a 14 MB machine can also be written for a 4 MB machine - but not with the amount and size of graphics and/or music possible on the 14 MB machine. Now about the FPU. Despite the fact that declaring an empty slot as a standard sounds pretty silly to me - an FPU is not really necessary indeed for most demos. The FPU usually makes sense when high precision is needed and you don't have that in demos very often ... ... but not very often does not mean never. Besides that, the FPU allows to handle floating point mathematics easily and that is growing more and more important in modern demos since they usually feature a lot of 3D effects. All of this can indeed be done without an FPU by having sin/cosin tables, but you're limited to fixed point then if you want to have it quickly and fixed point mathematics is not the same as floating point - For example, multiplying by 0.3 is pretty ugly in fixed-point math but easy as pie using the FPU and floating point maths. So yet again, you can basically write any effect using the FPU using the CPU instead, but you'll have to invest more work, probably have to recode essential parts and rounding-errors and the lack of precision might as well disturb the effect you are trying to achieve as well. What about FastRAM ? Do demos really need FastRAM ? Let me put it this way: The memory access in the Falcon is a drag. You could have a massive speedup in some calculation intense 3D effects if the CPU could access its own RAM and not having to share it with the Videl which makes the Falcon extremely slow in TC mode - and yet again, most demos run in True Colour since you have a chunky graphics mode then which is a lot friendlier to operate. Since FastRAM is not hard to add to the Falcon and could even be considered a natural add-on for an 68030 CPU based machine - Why not use it ? The natural consequence is the usual: You can do all effects possible with FastRAM of course also without FastRAM. However - FastRAM can speed up things massively. So finally - about accelerators ? Isn't that cheating in some way ? Well, i agree - the Falcon was initially intended to be a 16 MHz machine, Atari declared this as the standard configuration of the Falcon so simply using a faster machine to program more impressive effects might sound a bit PC-like ... If your code does not run fast enough, go buy a faster machine. On the other hand, we're in the year 2001 now and the Falcon is a machine from 1992. PCs have crossed the 1 GHz border some time ago and the Amiga scene is used to having 60 MHz 68060 or 200 MHz PowerPC processors for quite a while now and we argue about wether a demo has to be written to look good on a 16 or a 50 MHz 68030 machine. And as usual, any effect that runs on a 50 MHz Centurbo 2 can also be made to run on a 16 MHz Falcon - But most probably not in the same resolution, framerate or detail-level. You will have to live with some restrictions on an unaccelerated machine this way or other. Of course, it is easier to produce unoptimised code on an accelerated Falcon and it might look better than highly optimised code would look on an unaccelerated machine - But consider what possibilities the optimised code would have on an accelerated Falcon ... So let's conclude this chaper and as a result, we should note: Everything that is possible on an enhanced Falcon - using FPU, 14 MB RAM, an accelerator or FastRAM - is also possible on a non-enhanced Falcon without FPU, with only 4 MB RAM, no accelerator or FastRAM. Whatever demos are being produced for enhanced Falcons - and currently, this number is pretty low even though increasing - they can be made to run on a 4 MB, 16 MHz Non-FPU Falcon as well - but they will not look identical. You have to live with some restriction on the plain Falcon, no matter how well you optimise your code, cheat, use tricks and things like that - These tricks can also be used on the enhanced Falcon as well and produce even more stunning effects then. So the final message of this article is simply to show that both sides, those that try to declare the usage of any kind of enhancement the automatic death of the Falcon scene as well as those that heavily use add-ons, speeders and RAM expansions, are right to a certain degree. Enhancements should be considered with care and probably avoided where possible, but i personally rather have a demo using an FPU than no demo at all. Enhancements should not automatically be banned but considered as a new challenge for the coder in a way that the audience should be asked and asking: Was this demo worth the enhancements or could it have been done equally well without them ? Enhancements should be considered as "foreseen" by the way Atari designed the Falcon back in 1992 and not generally be treated as blasphemy - Yet again, coders and demo-designers should not overreact and write demos for massively enhanced machines just because they happen to own one. But on the other hand, a demo for an 68040 Falcon with 32 MB FastRAM, a Nova graphics card and 14 MB ST RAM would not find a lot of people to watch the demo so the restrictions for what a demo can run on are still pretty strict. I'd like to end this article with a short view on another part of the Atari scene which never really card about wether to use enhancements or not - The Atari 8-bit scene. Hardly any new-school demos run on 64KB, most newer demos require 128KB, if not even 256 KB by now. A simple 1050 hardly runs any demos but requires a "speedy" extension to watch most demos to increase transfer speed as well as diskspace available. In some cases - IIRC - demos sometimes even need a replacement DOS named Q-DOS to manage the extended memory. The other part of the Commodore scene is totally different to the Amiga scene as well: While many Amiga demos require at least an 68030 accelerator, favour 68040 or even 68060, some even require a PowerPC and while the Amiga scene even started to support graphic cards - The C64 scene does not take accelerators or enhancements for real. Basically _all_ C64 demos run on a plain C64 with 0.987 MHz, 64 KB and a normal 1541 - No replacement DOS, memory or diskdrive needed. So i guess the Falcon demo scene is somewhat in between and i do think that currently, this is a wise compromise. Let's see how all this continues and after reading this article, you might consider buying an FPU is not automatically cheating. :-) The <link=g35.scr>Paranoid</l> Written for my friend Grey's magazine "Chosneck" issue 1. </frame> </body>