Commodore 64 vs Atari 800 Xl

[Bryan]

And there you go. Another reason why these discussions are cool. Maybe good things happen, or bad things, like the buffer getting cleared.

 

Yoomp! gets a decent boost from using a line-doubled mode.

 

[PeteD]

A full on bitmap rotozoomer, at 1Mhz, without being able to sync the screen buffer change to the screen is tough... That's the crutch on the Apple. Everything was actually thought out really well but for that omission.

 

On the flip side, many of the cool bitmap graphics techniques used to reduce flicker probably came from Apple programmers, forced to get it done, for lack of the ability to sync with the raster.

 

 

 

Like I say though, if you saw it on an Apple, especially a good few years ago, would you care if it was kinda slow and sheared? I think I'd just grin at it for 10 mins

 

I think you're right about some of the techniques, if my memory wasn't so poor I'd be able to remember where I read some stuff about it..

[potatohead]

Yep. Agreed. One other element of value was software. The educational market penetration really helped on the software end of things, as well with the cards. Schools would buy Apples, and equip them with lots of interesting cards, so stuff actually got written for them.

 

On the technical computing end, those cards got written for too.

 

For me, the attraction was the nice 80 column display, productivity software, and the nice, open, documented ROM, complete with system monitor and mini-assembler, capable of line by line assembly. One had to deal with branches and keep track of labels, of course. Other than that, entering in assembly language programs wasn't a whole lot different from doing BASIC ones. It was common to put sound and sprite routines on the second text page, which often was unused, then call them from Applesoft, or better, the faster integer basic. All of it could be typed in, and debugged with the stuff in the ROM, no other tools needed. I missed that on every machine since. So, there was value, just a lot different value, not worth it to your average Joe wanting to do cool stuff on the computer value.

 

 

 

My main gripe with the Apple was the price. It had much less/simpler logic than most computers and could have been reduced to a small, inexpensive machine by turning the whole board into an ASIC. I realize it probably wasn't in Apple's best interest to do that, but I just didn't see the machine as a very good value unless you had need of a unique application that had been developed for it (usually something involving a card).

 

I do see the machine as being important in the evolution of the personal computer, and it directly influenced both the A8 and the 64. Atari wasn't even going to get into the computer market until Ray Kassar decided to compete with the Apple II.

 

The thing that makes the A8 and 64 cool are the custom chips. Big hunks of circuitry with a friendly sounding name.

[PeteD]

And there you go. Another reason why these discussions are cool. Maybe good things happen, or bad things, like the buffer getting cleared.

 

Yoomp! gets a decent boost from using a line-doubled mode.

 

 

Yeah, definitely a case of, you can, it doesn't look shit, it makes it faster, why not ?

 

If you try to use it as a comparison with what the C64 can do there'll be a lot of "but it's 1/2 the res", but it's a function of the machine and if you could do it on C64 without losing cycles...

[potatohead]

And there you go. Another reason why these discussions are cool. Maybe good things happen, or bad things, like the buffer getting cleared.

 

Yoomp! gets a decent boost from using a line-doubled mode.

 

 

Yeah it does. That one is a very good piece of retro art, that hits on the machine strengths very nicely. IMHO, that one could use some ports forward to bigger, faster hardware.

[potatohead]

Yeah, deffo. I would totally grin. Bad ass, hard core, old school. Nothing wrong with that.

 

There was a book I had in school, that I wish I still had, and it was a graphics book for the Apple. I think Chris Crawford wrote it. Anyway, I kind of want a copy today, because it went through all the basics. Masking, scrolling, flicker, you name it, and was all about getting stuff done on the Apple high-res screen. Great assembly reference for any computer actually.

 

I use that info all the time, when faced with single buffer scenarios. On a single buffer, one either has to chase the raster, doing each frame as a unit, or employ a variety of draw techniques to trade flicker for tearing, or speed and such... All of that was relevant on the Apple, but can be applied elsewhere. I've done a bit of it on the Prop, where there wasn't enough room or time to dynamic draw or double buffer.

 

 

 

A full on bitmap rotozoomer, at 1Mhz, without being able to sync the screen buffer change to the screen is tough... That's the crutch on the Apple. Everything was actually thought out really well but for that omission.

 

On the flip side, many of the cool bitmap graphics techniques used to reduce flicker probably came from Apple programmers, forced to get it done, for lack of the ability to sync with the raster.

 

 

 

Like I say though, if you saw it on an Apple, especially a good few years ago, would you care if it was kinda slow and sheared? I think I'd just grin at it for 10 mins

 

I think you're right about some of the techniques, if my memory wasn't so poor I'd be able to remember where I read some stuff about it..

[Bryan]

Yep. Agreed. One other element of value was software. The educational market penetration really helped on the software end of things, as well with the cards. Schools would buy Apples, and equip them with lots of interesting cards, so stuff actually got written for them.

 

On the technical computing end, those cards got written for too.

 

For me, the attraction was the nice 80 column display, productivity software, and the nice, open, documented ROM, complete with system monitor and mini-assembler, capable of line by line assembly. One had to deal with branches and keep track of labels, of course. Other than that, entering in assembly language programs wasn't a whole lot different from doing BASIC ones. It was common to put sound and sprite routines on the second text page, which often was unused, then call them from Applesoft, or better, the faster integer basic. All of it could be typed in, and debugged with the stuff in the ROM, no other tools needed. I missed that on every machine since. So, there was value, just a lot different value, not worth it to your average Joe wanting to do cool stuff on the computer value.

 

Apple was definitely a different kind of company. If the 800 had been released by the old Nolan Atari (which wouldn't have happened anyway) I think it would have been promoted in a totally different (hipper) way.

[+SpiceWare]

That's actually not true. When you switch off the screen everything is the color in COLBK. Change that on the fly and you have wall-to-wall RAINBOWS!!

Interesting - thanks for the info!

[potatohead]

Seriously. The 800 being locked down for so long was a big limitation. The thought then was that Atari software would be superior software, because Atari knew all the tricks to the custom chips.

 

The reality ended up being clever people hacking on the machine and documenting it to open it up, but it all went slowly. The other reality was Atari was constrained by it's own vision of how the stuff worked, not pushing it much at all.

 

All of that added up to the really great works happening late, after other things were seen on other machines, and the time advantage was lost It's too bad really. Ataris had a lot of great engineering in them for the time. The SIO system, with device independent I/O, and the killer basic in such a small ROM was really well done too.

 

I think a more friendly and fun approach would have seriously changed things, attracting a lot more early attention, which would have impacted the later parts of the product life cycle. Open has it's advantages too. Apples were sold through '92, I think!! Crazy, given how dated they were by that time. IMHO, that and the PC* are two very important object lessons in early home computing.

 

*not as open, but did feature all the other elements found in the Apple. Slots, business quality display capability, etc...

 

 

 

Yep. Agreed. One other element of value was software. The educational market penetration really helped on the software end of things, as well with the cards. Schools would buy Apples, and equip them with lots of interesting cards, so stuff actually got written for them.

 

On the technical computing end, those cards got written for too.

 

For me, the attraction was the nice 80 column display, productivity software, and the nice, open, documented ROM, complete with system monitor and mini-assembler, capable of line by line assembly. One had to deal with branches and keep track of labels, of course. Other than that, entering in assembly language programs wasn't a whole lot different from doing BASIC ones. It was common to put sound and sprite routines on the second text page, which often was unused, then call them from Applesoft, or better, the faster integer basic. All of it could be typed in, and debugged with the stuff in the ROM, no other tools needed. I missed that on every machine since. So, there was value, just a lot different value, not worth it to your average Joe wanting to do cool stuff on the computer value.

 

Apple was definitely a different kind of company. If the 800 had been released by the old Nolan Atari (which wouldn't have happened anyway) I think it would have been promoted in a totally different (hipper) way.

[Bryan]

That's actually not true. When you switch off the screen everything is the color in COLBK. Change that on the fly and you have wall-to-wall RAINBOWS!!

Interesting - thanks for the info!

You're welcome. I thought about what I wrote before, and you can actually manipulate the PMG's fully without any DMA. You just have to cram the HPOS and the GRAF registers yourself. In this mode, you can configure GTIA to be very much like TIA. You can set the Player pixels to be as wide as a TIA playfield pixels and stuff and position them in real-time to simulate a playfield. Use whatever's left for the players (as long as you don't need the repeat function).

 

I wonder what the best game is someone could write with no DMA.

[Bryan]

Seriously. The 800 being locked down for so long was a big limitation. The thought then was that Atari software would be superior software, because Atari knew all the tricks to the custom chips.

 

The reality ended up being clever people hacking on the machine and documenting it to open it up, but it all went slowly. The other reality was Atari was constrained by it's own vision of how the stuff worked, not pushing it much at all.

 

TI suffered from the same philosophy. They went so far as to modify the design to break 3rd party software.

 

*not as open, but did feature all the other elements found in the Apple. Slots, business quality display capability, etc...

 

As soon as the PC was cloned, it became as open as it gets!

[potatohead]

Yeah, totally on the PC. The only real difference being no friendly tools shipped on the machine. One could load DOS, and from there boot all kinds of stuff. Apples were great tools in and of themselves.

 

The PC BIOS is a layer that isn't really exposed to the user like was done on the Apple, complete with schematics and timing information. Building your own Apple card was expected, as was using the ROM. On the PC, it's open, but not really on that do it yourself level, otherwise agreed!

 

 

 

Seriously. The 800 being locked down for so long was a big limitation. The thought then was that Atari software would be superior software, because Atari knew all the tricks to the custom chips.

 

The reality ended up being clever people hacking on the machine and documenting it to open it up, but it all went slowly. The other reality was Atari was constrained by it's own vision of how the stuff worked, not pushing it much at all.

 

TI suffered from the same philosophy. They went so far as to modify the design to break 3rd party software.

 

*not as open, but did feature all the other elements found in the Apple. Slots, business quality display capability, etc...

 

As soon as the PC was cloned, it became as open as it gets!

[potatohead]

I have often wondered that myself.

 

 

 

That's actually not true. When you switch off the screen everything is the color in COLBK. Change that on the fly and you have wall-to-wall RAINBOWS!!

Interesting - thanks for the info!

You're welcome. I thought about what I wrote before, and you can actually manipulate the PMG's fully without any DMA. You just have to cram the HPOS and the GRAF registers yourself. In this mode, you can configure GTIA to be very much like TIA. You can set the Player pixels to be as wide as a TIA playfield pixels and stuff and position them in real-time to simulate a playfield. Use whatever's left for the players (as long as you don't need the repeat function).

 

I wonder what the best game is someone could write with no DMA.

[PeteD]

That's actually not true. When you switch off the screen everything is the color in COLBK. Change that on the fly and you have wall-to-wall RAINBOWS!!

Interesting - thanks for the info!

You're welcome. I thought about what I wrote before, and you can actually manipulate the PMG's fully without any DMA. You just have to cram the HPOS and the GRAF registers yourself. In this mode, you can configure GTIA to be very much like TIA. You can set the Player pixels to be as wide as a TIA playfield pixels and stuff and position them in real-time to simulate a playfield. Use whatever's left for the players (as long as you don't need the repeat function).

 

I wonder what the best game is someone could write with no DMA.

 

You want to make A8 coding HARDER?

[Bryan]

You want to make A8 coding HARDER?

 

...and you can only use 128 bytes of RAM, and your code must fit in 4K, and you can only use opcodes whose bits would generate even parity.

[TMR]

No, the A8 clocks the CPU faster and that's very different - if you're talking about 1.77MHz you're already talking about a processor and a machine wrapped around it at that point and that means there are other things that have to be considered.

 

Yes i understand your point, and that's how it works in reality.

 

Which is all anybody cares about...

 

But still, the main processor, and the mainprocessor only in A8 is faster clocked.

 

But that's the point everyone else keeps repeating, you can't seperate the A8 itself from the processor speed because the former governs the latter. Remove it from the A8 and plonk it into another machine and the clock speed will be whatever the new environment tells it to be. They're not directly compatible in the real world so swapping the processor from an A8 into a C64 wouldn't work but if it could be done the 6502 would simply crank down to 0.985MHz because the C64 hardware would be telling it to.

 

How fast A8 is, i don't know. But i do know one thing. A fast main processor is a good thing to have when making vektor graphics.

 

Only if it's attached to a well-designed video system as well. A fast processor with a crap display format is going to lag behind a slower one with a good format. And no, i'm not talking A8 vs C64 here (because the A8 is better served on that front, the C64's bitmap format is a clever fudge but harder to work with for it) the two machines that spring to mind as a prime example are the Amstrad CPC (with a 4MHz Z80a) and Spectrum (using a 3.5MHz Z80a) where the latter can be significantly quicker in practise because it only has to juggle half the memory each refresh.

[TMR]

You want to make A8 coding HARDER?

 

...and you can only use 128 bytes of RAM, and your code must fit in 4K, and you can only use opcodes whose bits would generate even parity.

 

Well, apart from the silly bit at the end someone tried to run a competition on AA with those rules a while back... but i forget if it went anywhere!

[Bryan]

You want to make A8 coding HARDER?

 

...and you can only use 128 bytes of RAM, and your code must fit in 4K, and you can only use opcodes whose bits would generate even parity.

 

Well, apart from the silly bit at the end someone tried to run a competition on AA with those rules a while back... but i forget if it went anywhere!

I seem to remember that too.

[NorthPole(heeHAW)]

DX!

 

Help, why doesn't this work?

 

10 PRINT "HELLO WORLD!";

20 GOTO 1

 

 

Aaron

[Bryan]

Cuz u need a space btween GO and TO. Duh!

[ANTIQ]

A no-DMA demo competition would be great to see!

[TMR]

Cuz u need a space btween GO and TO. Duh!

 

You git Bryan, it's been over twenty five years since i wrote anything in BASIC on the A8 - i just had to go and feckin' check to see if that was true! =-)

[PeteD]

You want to make A8 coding HARDER?

 

...and you can only use 128 bytes of RAM, and your code must fit in 4K, and you can only use opcodes whose bits would generate even parity.

 

Well, apart from the silly bit at the end someone tried to run a competition on AA with those rules a while back... but i forget if it went anywhere!

 

Add, "fighting off hordes of Playboy models" just to make it that bit harder (..errm, yes, I did just type that didn't I) and I'm in.

[Bryan]

Cuz u need a space btween GO and TO. Duh!

 

You git Bryan, it's been over twenty five years since i wrote anything in BASIC on the A8 - i just had to go and feckin' check to see if that was true! =-)

Glad to be of service.

[DimensionX]

DX!

 

Help, why doesn't this work?

 

10 PRINT "HELLO WORLD!";

20 GOTO 1

 

 

Aaron

 

Perhaps because it's similar to one of my smaller problems? I'm trying to work out if quantum fluctuation is a result of movement of energy between two non linear dimensions.

 

You would certanly like my theory about time and reality.

 

Btw, by looking at your code, how are your games look?

 

I think that your code should be suitable for a wordcross perhaps.

Edited May 9, 2010 by DimensionX