Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!sdd.hp.com!mips!apple!altos!vsi1!zorch!amiga0!mykes From: mykes@amiga0.SF-Bay.ORG (Mike Schwartz) Newsgroups: comp.sys.amiga.programmer Subject: Re: 2.0 Compatibility Message-ID: Date: 2 May 91 23:54:37 GMT References: <1991Apr30.133904.12649@msuinfo.cl.msu.edu> Organization: Amiga makes it possible Lines: 90 In article <1991Apr30.133904.12649@msuinfo.cl.msu.edu> jap@convex.cl.msu.edu (Joe Porkka) writes: >mykes@amiga0.SF-Bay.ORG (Mike Schwartz) writes: > >>I'm posting this with no intention of starting a flame war... >Nor do I intend to. I'm not trying to flame you, just a difference >of opinion here - take no offence please. > >>The Macintosh family of computers has been successful because Apple has >>forced people to adhere strictly to the use of the OS for even the most >How can Apple force people to do anything? I'll tell you, read on... They don't publish complete hardware manuals, they don't define a specific video architecture (planar, chunky, bits per pixel, etc.). They specifically tell you that (and which) specific hardware features are likely to change. You are right, that you can make software that works for just one specific display adapter (that goes to the hardware), but it just isn't done. Apple has also radically revved their OS several times, while Commodore has only done it once (2.0). 1.3 is pretty much the same as 1.0 with a few graphics library additions and lots of bugs fixed. >>primitive operations. Unfortunately, the Amiga OS is designed to allow >>multiple applications to share and directly manipulate the hardware. It >Actually, it provides support so most applications do not need to >acess the hardware directly. It does supply a means to get at the >hardware in an OS friendly way should you need to. >>is quite common on the Amiga for an application to bypass the graphics > ^^^^^^^^^^^ you must mean game. No, I mean application. DPaint uses the blitter directly. There are other programs like BLITZ and CygnusEd that use custom drawing routines for fast text that don't rely on the OS. Any application that uses OwnBlitter() or allocates other resources (floppy drives, CIA features, etc.) are likely to break. >>library and use the blitter (directly) or the cpu to render directly into >>bitplanes. All these applications won't work on a radically different >>display device (such as the lowell one). > >Hm, Apple developers have only been forced to play by the rules >because of the variety of AppleOS's and hardware in use. > >I suspect the same to happen with the Amiga. If a program has >played by the rules, it will work on a A3000 with 2.0. >Up until the A3000 there really wasn't any different Amiga hardware, >From a programs point of view, the A1000, A500, A2000 are 99% identical. > Even with the 3000, if you don't use the OS, the machines are 100% identical. They all have CHIP RAM at the same addresses (at bootsector time), all have register compatible blitters, copper, CIA timers in the same address locations. This is why 1.3 still works on a 3000. >Some hardware change has already happened. Remeber how many programs >(games and applications alike) broke when people started adding >non-CHIP expansion memory? 1meg chip memory? >HardDrives also caused (and still are) compatibility problems. > >So the lesson is, the more diverse the Amiga hardware in use, the >better quality the software will *have* to be in order to function >on all the machines. This means that programmers will have to >follow the rules in the RKMs more closely. > Programs that follow the rules in the RKMs *exactly* are already having problems with 2.0. For example, 2.0 allows you to change the default screen and window fonts. Try changing to a 15 point font and watch menustrips get screwed up! The whole point of my posting is that there is NO way to maintain compatibility given the direction things have and are going. >Do you have the gam MindWalker? It was written for AmigaDOS 1.0!, and >yet it actually runs on a A3000, not perfectly, but it does not crash. >Whoever wrote that game followed the rules, as well as they where >defined in 1.0 days, and so the program still works many years later. MindWalker was written PRE 1.0. If you know the early history of the Amiga, (not assuming you don't :) the OS radically changed from Beta rev. to Beta rev. breaking all the software that developers were working on. Many developers ignored most of the OS to make their code stable with future Betas. Have you seen Sonix? It was called MusicCraft a long time ago. Have you tried it on an A3000? I haven't, but it is also a program that was developed PRE 1.0, and it pokes the hardware a lot more than the RKMs say you should, or at least violates the suggested methods. -- **************************************************** * I want games that look like Shadow of the Beast * * but play like Leisure Suit Larry. * ****************************************************