The Composite Component-Based OS

This is the source code for the Composite component-based OS. Even low-level system policies such as scheduling, memory mapping, and synchronization are defined as discrete user-level components. Each component exports an interface used to harness its functionality, and components are composed together to form an executable system.

Please see www.seas.gwu.edu/~gparmer/composite for publications and more information.

Research features of Composite

• Component-based system construction -- All system software, from applications to the most low-level OS policies, is implemented as components. Components interact to harness each other's functionality and create an executable system. The power of this model is that the system is customizable -- policies can be replaced given the system's goals, the system software is reusable -- the same scheduler used in in the kernel can be used in an application, and the system is dependable -- each component can be isolated from each other so a fault or compromise in one, doesn't necessarily impact the other.

• Mutable protection domains -- hardware protection boundaries can be raised or lowered dynamically and in a controlled manner to trade fault isolation for performance

• Hierarchical resource management (HiRes) -- resource management decisions concerning CPU, memory, and I/O can be delegated to applications so they can control their allocations. However, even malicious subsystems cannot use this power to interfere with other subsystems. In many ways this is a generalization of virtualization.

• Memory scheduling -- memory in Composite is dynamically transferred between protection domains in the system based on the percieved impact that the additional allocation will make on predictability and performance while minimizing memory usage. In this way memory is "scheduled" by allocating it over a window of time to specific parts of the system.

• User-level, configurable scheduling -- threads and interrupts are scheduled by user-level components. The Composite kernel does not have a scheduler!

• Secure bulletin board system -- Composite was used in the verifiable election based on Scantegrity in Takoma Park, MD. It provided a secure webpage for verifying ballots after the election.

Where to start -- a tour of the source code

• Please read the doc/ directory for more information on how the code is organized
• Join the compositeos@googlegroups.com mailing list

Composite system support

• x86-32
• booting using Linux 2.6.33 or 2.6.36 (see Hijack support for booting information)
• networking using Linux drivers and a modified tun/tap driver to communicate with Composite

Important note

The code is pre-alpha quality. Some parts are quite solid, many others are absolutely not. Please consult with us to determine if it is right for your use-case.

Licensing

This code is licensed under the GPL version 2.0:

The Composite Component-Based OS
Copyright (C) 2009 Gabriel Parmer

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

This license is not set in stone, and we would be willing to negotiate on a case-by-case basis for more business-friendly terms. The license should not prevent you from using this OS, as alternatives can be arranged. It should prevent you from stealing the work and claiming it as your own.