imposing minimal conditions on the use of the copyrighted material. Material with Berkeley copyrights, or copyrights closely adhering to the Berkeley model can generally be included in OpenBSD. AT&T As part of its settlement with AT&T, Berkeley included an AT&T copyright notice on some of the files in 4.4BSD lite and lite2. The terms of this license are identical to the standard Berkeley license. Additionally, OpenBSD includes some other AT&T code with non-restrictive copyrights, such as the reference implementation of awk . Caldera Caldera (now known as the SCO group) is the current owner of the Unix code copyrights. On 23 January 2002, the original Unix code (versions 1 through seven, including 32V) was freed by Caldera. This code is now available under a 4-term BSD-style license . As a result, it is now possible to incorporate real Unix code into OpenBSD (though this code is quite old and generally requires significant changes to bring it up to date). DEC, Sun, other manufacturers/software houses. In general OpenBSD does not include material copyrighted by manufacturers or software houses. Material may be included where the copyright owner has granted general permission for reuse without conditions, with terms similar to the Berkeley copyright, or where the material is the product of an employee and the employer's copyright notice effectively releases any rights they might have to the work. Carnegie-Mellon (CMU, Mach) The Carnegie-Mellon copyright is similar to the Berkeley copyright, except that it requests that derivative works be made available to Carnegie-Mellon. Because