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Preface to the Third (2000) Edition
A great deal has happened to Plan 9 in the five years since its last
release. Although much of the system will seem familiar, hardly any aspect
of it is unchanged. The kernel has been heavily reworked; the graphical
environment completely rewritten; many commands added, deleted, or
replaced; and the libraries greatly expanded. Underneath, though, the same
approach to computing remains: a distributed system that uses file-like
naming to access and control resources both local and remote.
Some of the changes are sweeping:
Alef is gone, a casualty of the cost of maintaining multiple
languages, compilers, and libraries in a diverse world, but its
model for processes, tasks, and communication lives on in a new
thread library for C.
Support for color displays is much more general, building on a new
alpha-blending graphical operator called draw that replaces the
old bitblt. Plan 9 screens are now, discreetly, colorful.
A new mechanism called plumbing connects applications together in
a variety of ways, most obviously in the support of multimedia.
The interfaces to the panoply of rotating storage devices have
been unified and extended, while providing better support for
having Plan 9 coexist with other operating systems on a single
Perhaps most important, this release of the system is being done
under an open source agreement, providing cost-free source-level
access to the software.
Plan 9 continues to be the work of many people. Besides those mentioned in
the old preface, these people deserve particular note: Russ Cox did much
of the work updating the graphics and creating the new disk and bootstrap
model as well as providing a number of new commands; David Hogan ported
Plan 9 to the Dec Alpha; and Sape Mullender wrote the new thread library.
Other new contributors include Bruce Ellis, Charles Forsyth, Eric Van
Hensbergen, and Tad Hunt.
Murray Hill NJ
Copyright (c) 2000
Lucent Technologies Inc.
All rights reserved.