evaluation 4/20

Vagelis Hristidis (vagelis@cs.ucsd.edu)
Thu, 20 Apr 2000 01:46:57 -0700

StarOS, a MultiProcessor Operating System for the support of Task Forces

Task forces are large collections of concurrently executing processes that
cooperate to accomplish a single purpose. SrarOS is an OS that was developed
for the Cm* multi-microprocessor. The goals are to perform the task quickly
( using parallelism), reliably (no process should perform an indispensable
function) and to have scalability. Each process has a small and restricted
address space. Processes communicate and synchronize using semaphores and
mailboxes.
StarOS is object-oriented. Each object contains a data portion and the
capability list portion. StarOS introduces an event mechanism for processes
communication. There are two types of functions: instructions which have to
execute sequentially and asynchronous, where the invoking process may
continue its execution in parallel. Emphasis is also given to the
dependencies between processes.

Medusa: An Experiment is Distributed Operating System Structure

Medusa is a multi-user , distributed OS, that was developed for the Cm*
multi-microprocessor. The goals are modularity, robustness and performance.
It is interesting that due to the small memories of the modules, only a
portion of the OS is kept for each processor, so not all processors can
perform all tasks. Deadlocks are also nicely avoided. Exceptions are also
supported by the system. In general Medusa is an object-oriented system with
a highly distributed structure that closely matches the hardware.