Shared structures are: At the process level: -> File system (only matadata and data caches) -> Task manager table -> Task vm_region if we support inter process com (not the case in almos) specific to ALMOS: -> DQDT to allocate the approprite proc/mem ( can be avoided for now by directly using the the task next_cluster field, and always redirecting the allocations to the local cluster) -> Efficient com with other proc: - devellope physical access techniques at the software level - fine grained at the C language level - at the assemebler level, by inserting macro to switch space - get some help from the hardware (put an paddr_extension for the stack (most important) and one for the instructions (secondary) )