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AcadOS, an Academic Operating System

Douglas W. Jones
University of Iowa Department of Computer Science

22C:294-2 Seminar on Systems and Networks, Spring 2001, B11 MacLean Hall, 2:30-3:20 MW(F).



Among the students involved in the 2002 AcadOS venture are:


The development of ACADOS was motivated by three factors. First, we note that the dominant operating systems today are versions of MS-Windows and versions of Unix. Windows owes much to MS-DOS, a system with no distinguished lineage, and it owes much to VMS, DEC's old operating system for the VAX family of machines. All of these systems date from the 1970's!

Operating systems from the 1970's are characterized by some assumptions that are no longer true. They tend to assume that memory is relatively scarce, or rather, that the memory address space is relatively small. They tend to make minimal assumptions about the memory management unit, and they tend to assume a simple two-level security model.

Much has happened in the years since Unix and the other great operating systems of the 1970's were developed, and our goal is to explore some of these ideas. As Christopher Marlin said about programming languages, it is occasionally necessary to step back and make a fresh start.

Our second motivation is the fact that the fundamental mechanisms discussed by most operating system texts are not readily apparent in most real operating systems. Where are semaphores or other elementary interprocess communication mechanisms in UNIX, for example? To the extent you can find them, they are afterthoughts, cobbled into the system, and as such, they make poor examples.

Our final motivation is the fact that students need more exposure to the problems of designing (and if time permits) prototyping operating systems and programming languages. As a class exercise, we hope this project will be a wonderful opportunity for serious lessons in practical software engineering.

Major Features of AcadOS

To be added as these features are pinned down.