Virtual Motorola 68000 "m68k" Machine With Up To 3.2GB RAM Expected For Linux 5.19

[phoronix]

Phoronix: Virtual Motorola 68000 "m68k" Machine With Up To 3.2GB RAM Expected For Linux 5.19

Being worked on for a while has been a more powerful Motorola 68000 "m68k" virtualization target. It looks like that new virtual machine target will come with Linux 5.19 for allowing m68k guests with up to 3.2GB of RAM and up to 128 VirtIO devices...

https://www.phoronix.com/scan.php?page=news_item&px=Virtual-m68k-Linux-5.19

[Chewi]

Finally! Just last weekend, I went through a rather painful process with a Google engineer trying to fix an m68k glibc bug, that was made much more difficult due to this not having been mainlined yet.

I better touch base with the author though, he appears to have forgotten one of the fixes I was testing for him!

[hamishmb]

This is cool.

It'd be nice if someday they'd add a PowerPC G5 machine of some kind for quicker PowerPC emulation - it'd still be slow, but lots quicker if I could use multiple CPU cores for it.

[danboid]

I can't believe Michael didn't mention the Amiga, which is what I always think of first when I read of the m68k. Instead I was searching "Tandy m68k" to find out what Tandy machines used it.

[danboid]

Why can it only address 3.2 GB and not 4 GB?

[Chewi]

Why can it only address 3.2 GB and not 4 GB?

I have wondered that, but given that my Amiga 1200 has 128MB, and a stock Amiga 1200 has 2MB, I'm not complaining!

[stesmi]

Why can it only address 3.2 GB and not 4 GB?

Generally on the m68k, with some exceptions, devices are memory mapped, so you simply write to memory addresses to talk to devices, so they "steal" space where you could have "real ram".

// Stefan

[ayumu]

I have wondered that, but given that my Amiga 1200 has 128MB, and a stock Amiga 1200 has 2MB, I'm not complaining!

You sure you don't have 130? (128mb 32bit fastram + 2mb chip)

[SteamPunker]

I can't believe Michael didn't mention the Amiga, which is what I always think of first when I read of the m68k. Instead I was searching "Tandy m68k" to find out what Tandy machines used it.

I was thinking the same thing. And the fact that Michael originally hails from Germany, where the Amiga was particularly popular, makes this omission even more awkward.

Anyway, the fact that the m68k architecture continues to thrive in virtual form to this day, supporting almost 4GB of RAM(!!!) and having first class support in Linux, really speaks for the amazing forward compatibility that the 68000 was endowed with when it was initially designed and developed. If only IBM had gone with the 68000 CPU in the original IBM PC design, instead of the 8088, the PC platform would have been so much nicer, with much smoother generational upgrades.

Maybe if Motorola had released the low cost 68008 variant a few years earlier. Alas.

[Waethorn]

Didn't they remove the floppy drive code already?