Hi, I was curious to know which core features of the Linux kernel are not implemented in the plan9 kernel. By core I mean that I know plan9 does not have all the drivers, filesystems, buses, etc Linux has, but it has many of its core features (virtual memory, paging, swapping, demand loading, copy on write, etc), and even more.
For instance I was not able to find any code related to the buffer cache Linux has. If you open a big file in a plan9 process, then close it, and later you open it again, will you pay the IO again? Or is it cached somewhere?