To boot a normal OS sure, but anything small enough to fit in registers/cache could do without RAM. That’s still some form of working memory though, so it’s probably not what they meant.
You could build something RAM-less if you only need the thing to process real-time events like some signal processing with only 1 pass (also see: tons of FPGA and DSP applications)
Yes I would count cache as a type of RAM. Also I don’t think the cache hierarchy would actually work without main memory as it’s foundation in a lot of cases. They are designed to have memory to map to. It would also be difficult in some systems to coordinate between cores as not every system has shared cache between all cores.
Would it be possible to forgo ram for just swap?
No it is not possible. For a more detailed explanation read here: https://askubuntu.com/questions/928308/is-it-possible-to-use-ubuntu-without-ram-at-all
But it’s possible with almost zero ram, like 32mb, but it’ll be a very slow experience
Yeah. That should work, but it will be slow as hell, since stuff has to be split up into 32mb blocks to be executed.
OpenWRT users beg to differ… kinda. 32mb is now very low and barely sufficient, but not that long ago it was just enough to run Linux
And that’s without any swap! Because guess what, flash size is even lower with only 4MB!
Yeah 32mb will suck but with swap space it’ll be usable
My hero
Actually, I believe it should be possible (albeit horrendously slow) by memory-mapping the disk to address space.
Absolutely not. Memory mapping is a concept created by the OS. The CPU won’t operate without RAM of some kind. It’s a fundamental hardware issue.
To boot a normal OS sure, but anything small enough to fit in registers/cache could do without RAM. That’s still some form of working memory though, so it’s probably not what they meant.
You could build something RAM-less if you only need the thing to process real-time events like some signal processing with only 1 pass (also see: tons of FPGA and DSP applications)
Yes I would count cache as a type of RAM. Also I don’t think the cache hierarchy would actually work without main memory as it’s foundation in a lot of cases. They are designed to have memory to map to. It would also be difficult in some systems to coordinate between cores as not every system has shared cache between all cores.
Maybe for the OS. Still the BIOS/UEFI requires phisical RAM to boot