RISC and especially MMU with paging increase memory requirements. For comparison, the first Amiga was designed for 128K, got 256K. Linux/M68K with MMU on the Amiga required 4MB to be usable.
RISC and especially MMU with paging increase memory requirements. For comparison, the first Amiga was designed for 128K, got 256K. Linux/M68K with MMU on the Amiga required 4MB to be usable.
While on the other hand, RAM is easely equal to all other chips on the board combined.
So you need to desperatly do everything you can to limit RAM usage. That's why Amiga was smart to do shared RAM between the CPU and the Chipset. The Archimedes did the same thing as well. And ideally you get some SRAM on there not depend on the RAM to much, ARM3 chip did that and speed improved by a huge extent.
And you really need a good operating system that could give you advanced features without completely blowing up your RAM.
That is why it is sad that nobody with sufficent capital to pump into costume chip design took on a project like that, as it needs to be somebody with the volume the economics work out.
But nobody did and instead we got there threw an iterative process where PC manufactures pumped out PC and bought the cheapest chips, while Intel and chip companies integrated the board more and more. I remember learning about Southbridge and Northbridge, and that essentially the design you end up with.
The least they should have done was actually shipping Fast Ram controller (with unpopulated ram) in every single Amiga model since 1987 A500. Instead we got trapdoor expanding shared slow/chipset ram with very limited addressability.
Atari for what is worth quickly standardized on using SIMM sockets right on the motherboard and supported 4MB.
I think Amiga was fine at reading the room, at least the engineers. But the never did any signifciant chip develpement to improve things. Only the new chipset for the Amiga 1200 when it was already much to late.
https://forums.atariage.com/topic/207245-secret-atari-dram-r... https://web.archive.org/web/20180817061246/https://www.atari... TLDR up to $6Mil a month of smuggled ram from Japan by Atari to make money on a side :)
https://web.archive.org/web/20171220171525/https://www.atari...
"Source [an informant to the FBI who is apparently an Atari employee] remembers the first DRAM shipment arriving in 1988 was sold to Sun Micro Systems in Milpitas, CA. Source was told to deliver this shipment by [redacted]. [redacted] told Source to leave all [redacted] including his [redacted] and to take [redacted] which had an Atari logo on them. When Source delivered the Integrated Circuits, [redacted] cashier's check from Sun Microsystems to deliver to Atari, and the payee's name was left blank."