EROS: The Extremely Reliable Operating System

EROS is a new operating system being implemented at the University of Pennsylvania. The system merges some very old ideas in operating systems with some newer ideas about performance and resource management. The result is a small, secure, real-time operating system that provides orthogonal persistence.

Effective April 14, 1999, the EROS website has moved to Please update your links.

NEW:(04/23/99) EROS Release 1.0. EROS is finally released! Check out the release notes and the license.

NEW:(04/22/99) Dissertation Now Online. Shapiro's dissertation, which describes a fair bit of the EROS internals and some of the formal results, can now be obtained from here.

NEW:(10/26/98) Mailing List Archives Now Online. Several of the EROS mailing list archives can now be found online here.


Where to go from here

What's New About the EROS System?Release Notes
Meet the EROS TeamCurrent Project Status
Distribution TermsTechnical Documentation and Papers
Design NotesNotes on the Dionysix Design
Mailing ListsIntroductory Essays
Frequently Asked QuestionsBrowsable EROS Source
 The KeyKOS System (EROS's predecessor)

If you decide to download the system, we recommend that you join the EROS mailing list be subscribing to theeros-portmailing list. Instructions for doing so can be found here.

If you were fond of the old name jokes, they can now be found here.

This site is part of the Computer Security Fact Forum, which takes advantage of Ka-Ping Yee's CritLink tool to allow third parties to coment on what they see. The Computer Security Fact Forum is a project of the Foresight Foundation. To view this site through CritLink, click here.


Project Support

This research was supported by DARPA under Contracts #N66001-96-C-852, #MDA972-95-1-0013, and #DABT63-95-C-0073. Additional support was provided by the AT&T Foundation, and the Hewlett-Packard, Tandem Computer, and Intel Corporations.

Copyright 1999 by Jonathan Shapiro. All rights reserved. For terms of redistribution, see the EROS License Agreement