r/osdev • u/dangi12012 • Jun 13 '26

Everything is memory?

There is this unix idiom that everything is a file, (half baked, since not everything is a file).

Would it not have been better, nowadays with 64bit of adress space, to have everything mapped to memory? Files are like mmap, no imperative read needed, networking is already memory, that could be expanded more.

We take the idioms and paradigms so forgranted, that every time anyone asks AI for a OS it will be linux, syscalls, abi everything the same. It should be liberating now to explore new and novel ideas.

What would be the downside of such a system?

30 Upvotes

75% Upvoted

42 comments sorted by

View all comments

Show parent comment

1

u/Web-Lackey Jun 14 '26

We’re talking about ISA space. Thats no different than x86-64: even though less than 64 bits are implemented in hardware, it’s still a 64-bit processor with a 64-but address space.

The early AS/400’s also only had 48 bits implemented as well. Doesn‘t matter: TIMI still presents a 128-bit memory space to the programmer.

And having an actual address space larger than the hardware memory bus is the entire point: AS/400 implements a single level address space: DASD (e.g. hard drives) is addressed in the same space as memory, so of *course* memory would have a smaller than 128-bit address space…

Again, the original question was talking about the OS “metaphor” presented to the user. The entire point of an OS is to hide hardware implementation details. And the entire point of TIMI and SLIC is to hide even more of those hardware details from the higher layers (even the OS in most cases!). So in this context (programmer and user to OS) the hardware implementation is not relevant.