New semester, new version of the xv6 educational OS for RISC-V from MIT! This is accompanied by a new revision 5 of the xv6 book and–for the first time, I think–a Lions' Commentary-style code reader booklet!
A previous version switched to using the stimecmp extension instead of the regular CLINT timer, that was a bit of a surprise. So let's see what the changes in this new version are...
https://pdos.csail.mit.edu/6.1810/2025/xv6/book-riscv-rev5.pdf
https://pdos.csail.mit.edu/6.1810/2025/xv6/xv6-src-booklet-rev5.pdf
https://github.com/mit-pdos/xv6-riscv