We might be able to circle back to this now by putting some portion of memory and video on the die along with the CPU, but that was not going to happen for Atari and Commodore back in the 90s. Motorola wasn't going to shove 128KB or whatever of RAM into a 68k just for them, and even if they did it would have been so expensive
Memory speeds plateau'd while CPU speeds skyrocketed. Almost all the complexities of modern architectures have to do with this. There used to be "no need" for something as funky as L1/L2/L3 caches really because often your memory was faster than your CPU (hence why something like the C64's VIC-II or the Atari ST's "Shifter" are even possible).
Hell there were systems back then that didn't even have onboard registers in the CPU, but used external memory for it (TI's TMS series). The 6502's "zero page" is another example.
You can't do that anymore. The CPU will run many laps around your memory.
Still it'd be interesting to see what Jay Miner would have come up with in the late 90s or 21st century, if he was still around and in the game.
Unified memory is more about taking advantage of zero copy access for the GPU. Since everything the GPU wants is already right there there's no need to send it on a trip over a bus into separate GPU memory. Memory bandwidth is of course still important for both the GPU and CPU so that unified memory can be a bottleneck if it's slow or has too few channels.
The combination with “There's no abstracted API for doing the fancy graphics (at least not one used by games, etc)” only works as long as you have a solid unique benefit, and that, Amiga lost fairly rapidly due to Moore’s law.
It lasted pretty long, especially considering the rate of evolution in those days. It debuted already in 1985, and there were some incremental improvements along the way (first the A3000 and then AGA A4000/A1200 in 1992). After the biggest lead in graphics started to shrink you still had a big user and software user base, multitasking desktop that was far ahead at least until W95, great CLI environment compared to PC stuff, competitive price etc.
> and there were some incremental improvements along the way (first the A3000 and then AGA A4000/A1200 in 1992)
About the A3000 Wikipedia says “The machine is reported to have sold 14,380 units in Germany (including Amiga 3000T sales)”, and about the A4000 “The machine is reported to have sold 11,300 units in Germany”. Both were on sale for about 2 years.
In comparison, the A2000 sold 124,500 units in Germany, again according to Wikipedia, in the about 4 years of its commercial availability.
So, about a 80% decline in sales per month, in what I think/guess was an expanding market for personal computers.
⇒ I don’t think those improvements made much of a difference.
The A3000 was more than twice as expensive. The A4000 even more expensive. They were not mass market machines.
Variants of the A2000 continued in the market after the A3000 was released, such as the A2500, so people who didn't need the upgrades - or could make use of them (e.g. the VideoToaster didn't fit in the A3000 case without modifications) would continue to buy cheaper models.
.. And the 1992 Amiga 600 and 1993 1200 sold 193k/95k. The volume was always in the A500 form factor machines that used a TV as the display half the time.
Commodore's focus on low cost stuff (in their own way) while PC clones managed to push the HDD+SVGA setup price down was a critical factor for how things turned out I think. In the high end there was also Apple, Macintosh had launched a year before the Amiga and made the
professional GUI market harder to enter.
But the fateful focus also let the masses have access to a great hacker's computer growing up, without the vibe satirized by "Office Space" that marked the Microsoft platforms.
Memory speeds plateau'd while CPU speeds skyrocketed. Almost all the complexities of modern architectures have to do with this. There used to be "no need" for something as funky as L1/L2/L3 caches really because often your memory was faster than your CPU (hence why something like the C64's VIC-II or the Atari ST's "Shifter" are even possible).
Hell there were systems back then that didn't even have onboard registers in the CPU, but used external memory for it (TI's TMS series). The 6502's "zero page" is another example.
You can't do that anymore. The CPU will run many laps around your memory.
Still it'd be interesting to see what Jay Miner would have come up with in the late 90s or 21st century, if he was still around and in the game.