Multi-processing as discussed in final classes: the ability to
have multiple processing running different programs at the same
time, and those processes being unable to interfere with each
other, and switches between processes performed automatically
on timer interrupt.

The user sould be able to give basic commands interactively
to interact with the file system and see essential OS information,
stop/suspend a process, and start new processes.

The notes from class 27 say what needs to be done.

Your file system and heap memory system should of course work
with this OS.

Groups of three should have additionally
  Efficient inter-process communication
  Memory allocation and run-time quotas