This is such a delicious article for those of us who are 'retro-' computing enthusiasts. Made my Sunday cuppa shine!
"In a way, this feature is similar to the YM2149 ADSR envelope. Not technically, but because both features are mostly ignored by Atari and Amiga programmers! :)"
As an Oric-1/Atmos programmer, this line was especially juicy.
Using PAULA's attached mode is so brilliant, btw. I love it when things of this nature are discovered, decades after the fact. We've had a few such revelations in the Oric world too, none as powerful of course at Orics' 1MHZ, but nevertheless, the shoulders of the Atari/Amiga giants are perilously within reach for the climb ..
EDIT: Oh, COPPER and PAULA, paired at the bits. Such a great hack, this one ..
I was in a Dutch demo group first for msx and then amiga, then dropped out of low level dev; the amiga coprocessors I still miss. I went to PC as everyone did and definitely at the beginning thought: what is this garbage??? We lived in the future and then it was taken from us for a while.
Same feeling. I often think of the 16-bit PC era as kind of the dark ages. Everything was weird, nothing made sense, elegance nowhere to be found. Things got a lot better again when 32-bit PCs came around
and continued to improve with 64-bit.
Yeah, the closest you can get to those days is doing homebrew in something like PS3 cell units, or shader coding, which is kind of why shader competitions are so beloved in demoscene parties.
I don't know if the Amiga was ahead of its time or the PC was behind its time. AmigaOS was a pre-emptive multitasking OS whilst PCs had to wait for Windows NT/95.
While Windows 2 on an 8086 could pre-emptively multitask DOS apps, so long as they all fit into 640 kB at once. Windows/386 could do it in extended memory.
The innovative thing in W95 was doing it to Win32 apps as well.
OS/2 in 1987 or so could multitask OS/2 code on a 286.
The release of Windows 95 was weird. There were PC users talking about how amazing Microsoft were, to have come up with all the things their marketing people were shouting about, such as pre-emptive multitasking and plug-and-play. Then all the Amiga (and Mac) users, completely underwhelmed, pointing out "we've had all these things for years, how has it taken so long?".
Yeah. one thing is not like the other. While AmigaOS was pre-emptive, Mac System - 6-8 weren't. It was co-op. Everyone who used 6 and 7 can remember copying file meant you couldn't do anything else, and 8 got multithreaded support in Finder finally, but it was still co-op. At the time I used various platforms daily. Namely, AmigaOS, Mac System 6-8, IRIX.. the difference was obvious. IRIX and hardware of course being from the future, but at at least 10x the price.
Even Mac OS classic was just cooperative multitasking. Near the end it got some very limited pre-emptive capability, but most only usable to do calculations.
There were early multitasking operating systems starting with the 386, but for demos you'd typically use the entire CPU. Part of the magic was that video routines would run at an extremely constant 50 (or 60) Hz, perfectly in sync with the hardware. This, and color bleeding, resulted in a buttery smooth experience, that I still miss.
One particular example of this experience was that you'd use "raster bars" to time the performance of your routines. If your main loop is synchronized with the vertical retrace, then switching the background color after a piece of code would show up in the margins of your screen.
Animations were tuned to move in constant pixel offsets. All the anti-aliasing in the world cannot bring back the true demoscene spirit :)
I never had an Atari ST so wasn't familiar with the details of how its sound chip worked. I did know it was a variant of the AY chip found in the ZX Spectrum +2A, which I did own for a brief period after several years of 48K+ ownership.
However, it's only as a result of reading this article that I realised the chip is only capable of generating square waves and noise, whereas I'd been under the impression it had some slightly more advanced FM synthesis capabilities. That impression must have come from, decades later, listening to what people could squeeze out of the chip on various Spectrum demos on YouTube. Well, that and the fact that after the 48K beeper the 128K was never going to sound less than incredible. I might not even have had it for a year before switching to the (much less prone to go wrong) C64[0].
Anyway, all of this to say: very interesting project, and I enjoyed the neat reversal trick with the attached voice to get the higher quality output out of Paula.
[0] Actually the Spectrum -> C64 switch was more of a mixed bag than you might think - it wasn't, for example, like games on the C64 were all universally better. On the sound front, the C64's SID chip was a significant upgrade over the AY though, and certainly the most capable sound chip amongst 8-bit computers that I'm aware of. I really wish they'd crammed a SID chip into the Amiga alongside Paula. Or maybe even a dual SID with 6 channels for stereo output + Paula, but, alas... I'm sure it would have been cost prohibitive even if Commodore engineers had the idea at the time.
> Well, that and the fact that after the 48K beeper the 128K was never going to sound less than incredible
Some of the stuff people do with the 48k beeper is incredible though. Tim Follin's tunes for example are basically treating the beeper like a 1-bit DAC, with amazing results. https://www.youtube.com/watch?v=T42WuUpBuHE
Yeah, when I had the 48K Speccy I bought this and a shoot em up called Chronos, which wasn't by any means an amazing game (not bad for the £1.99 or £2.99 I paid for it, mind), but it was blessed with incredible intro music, which I think might have been another Tim Follin special.
It's not to say amazing results from the 48K beeper were impossible, but you had to work pretty hard for them, and you were definitely into wizardry territory.
But, it's also true that the sound capabilities of the 128K machine were a big step up (also worth bearing in mind you had the beeper and the AY chip - you weren't losing the beeper).
Aha - and as if by magic... yeah, I just mentioned that the 128K machine had both the beeper and the AY chip, and this is a great example of them in use together.
> I really wish they'd crammed a SID chip into the Amiga alongside Paula
This is something the Apple IIgs had. It had an extremely capable synthesiser with good graphics and performance capped so not to compete with Macs. It was a weird machine, a sharp contrast with the minimalistic Apple IIs that preceded, over complicated and trying to be too many things at once.
For the same reason I prefer the design of the ST over the Amiga’s. Amiga made lots of assumptions about the use that ended up tuning it well to platform games and NTSC video editing, but nothing else.
Important fun fact, this synthesizer was an Ensoniq chip (ES5503 DOC), designed by Bob Yannes, the inventor of the SID chip.
The IIGS was actually a cool machine, not very successful unfortunately.
"In a way, this feature is similar to the YM2149 ADSR envelope. Not technically, but because both features are mostly ignored by Atari and Amiga programmers! :)"
As an Oric-1/Atmos programmer, this line was especially juicy.
Using PAULA's attached mode is so brilliant, btw. I love it when things of this nature are discovered, decades after the fact. We've had a few such revelations in the Oric world too, none as powerful of course at Orics' 1MHZ, but nevertheless, the shoulders of the Atari/Amiga giants are perilously within reach for the climb ..
EDIT: Oh, COPPER and PAULA, paired at the bits. Such a great hack, this one ..
> AmigaOS was a pre-emptive multitasking OS
Yes, but without memory protection.
> whilst PCs had to wait for Windows NT/95.
While Windows 2 on an 8086 could pre-emptively multitask DOS apps, so long as they all fit into 640 kB at once. Windows/386 could do it in extended memory.
The innovative thing in W95 was doing it to Win32 apps as well.
OS/2 in 1987 or so could multitask OS/2 code on a 286.
One particular example of this experience was that you'd use "raster bars" to time the performance of your routines. If your main loop is synchronized with the vertical retrace, then switching the background color after a piece of code would show up in the margins of your screen.
Animations were tuned to move in constant pixel offsets. All the anti-aliasing in the world cannot bring back the true demoscene spirit :)
However, it's only as a result of reading this article that I realised the chip is only capable of generating square waves and noise, whereas I'd been under the impression it had some slightly more advanced FM synthesis capabilities. That impression must have come from, decades later, listening to what people could squeeze out of the chip on various Spectrum demos on YouTube. Well, that and the fact that after the 48K beeper the 128K was never going to sound less than incredible. I might not even have had it for a year before switching to the (much less prone to go wrong) C64[0].
Anyway, all of this to say: very interesting project, and I enjoyed the neat reversal trick with the attached voice to get the higher quality output out of Paula.
[0] Actually the Spectrum -> C64 switch was more of a mixed bag than you might think - it wasn't, for example, like games on the C64 were all universally better. On the sound front, the C64's SID chip was a significant upgrade over the AY though, and certainly the most capable sound chip amongst 8-bit computers that I'm aware of. I really wish they'd crammed a SID chip into the Amiga alongside Paula. Or maybe even a dual SID with 6 channels for stereo output + Paula, but, alas... I'm sure it would have been cost prohibitive even if Commodore engineers had the idea at the time.
Some of the stuff people do with the 48k beeper is incredible though. Tim Follin's tunes for example are basically treating the beeper like a 1-bit DAC, with amazing results. https://www.youtube.com/watch?v=T42WuUpBuHE
It's not to say amazing results from the 48K beeper were impossible, but you had to work pretty hard for them, and you were definitely into wizardry territory.
But, it's also true that the sound capabilities of the 128K machine were a big step up (also worth bearing in mind you had the beeper and the AY chip - you weren't losing the beeper).
https://www.youtube.com/watch?v=F1e2MOeo5eU
This is something the Apple IIgs had. It had an extremely capable synthesiser with good graphics and performance capped so not to compete with Macs. It was a weird machine, a sharp contrast with the minimalistic Apple IIs that preceded, over complicated and trying to be too many things at once.
For the same reason I prefer the design of the ST over the Amiga’s. Amiga made lots of assumptions about the use that ended up tuning it well to platform games and NTSC video editing, but nothing else.