exxos's Atari, Amiga & retro forum

I think I personally would choose the CT2 over my ct60e. Having to change between 030 mode and 060 mode for compatibility reasons is frustrating at times.

Steve wrote: 14 Jul 2018 11:17 I think I personally would choose the CT2 over my ct60e. Having to change between 030 mode and 060 mode for compatibility reasons is frustrating at times.

You'd be surprised how little difference is there between the CT2 and CT60 when it comes to compatibility. The biggest compatibility killer is naturally TT RAM (developers using BSS as screen/dma buffer I'm looking at you) and then CPU/DSP sync. Things like different PMMU unit, cache management, emulated instructions etc play very little role.

exxos wrote: 14 Jul 2018 10:08Of course not many people mention it does not even have 32bit access to ROM for example. It would have made huge increase in OS speeds simply to do that, and it is not really much work either.

This must have to do with the fact they hadn't planned using the 68030 and keeping the 68000 until the last minute. The 68000 bus mastering emulation (or whatever it is) has caused a lot of headache to many Falcon hardware developers.

And yes, I also wish living in a world where you would have more time for Falcon specific hardware. ;-)

mikro wrote: 14 Jul 2018 14:10 You'd be surprised how little difference is there between the CT2 and CT60 when it comes to compatibility. The biggest compatibility killer is naturally TT RAM (developers using BSS as screen/dma buffer I'm looking at you) and then CPU/DSP sync. Things like different PMMU unit, cache management, emulated instructions etc play very little role.

I think there's slightly more to it. The cache control registers are different as well, aren't they?

mikro wrote: 14 Jul 2018 14:15 This must have to do with the fact they hadn't planned using the 68030 and keeping the 68000 until the last minute.

It does look like a 68000 based system just with a 030 slapped on the bus without any other changes. Could be any number of reasons. Though maybe the 68000 couldn't clock reliable at 16mhz at the time and they moved to the 030 to correct that problem and thought it would be better speed wise due to caches and its a "030" "sales feature".. I mean 68000 had been around for a while and another 68000 based system doesn't seem a wise move. But a 030 seems like its more advanced machine. aka "better CPU , better machine" type ideals. Could also be supply issues of the 68000..

Though didn't the sparrow have a 030 ? Would seem Atari planned on using it from the start, just never spent any time on the CPU side of things for some odd reason.

mikro wrote: 14 Jul 2018 14:15 And yes, I also wish living in a world where you would have more time for Falcon specific hardware. ;-)

Maybe one day.. but likely someone else will beat me to it anyway.

dhedberg wrote: 14 Jul 2018 21:24I think there's slightly more to it. The cache control registers are different as well, aren't they?

Sure. And how many programs manipulate the CACR register? Screen/dma buffers in BSS are far more common.

exxos wrote: 15 Jul 2018 12:19 Though didn't the sparrow have a 030 ? Would seem Atari planned on using it from the start

From the internal Sparrow specification:

REV A10 10/22/91 changes:
[...]
page 2-68000 changed to 68030.

https://forum.atari-home.de/index.php?a ... tach=12961

So, initially they planned the Sparrow with a 68000 CPU, while the (never released) "real Falcon" would have had a 68030 or even 68040 CPU (and fast RAM).

Thanks. Also mentions 2 ROM's as well.