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
that replaces the old
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 disk.
Perhaps most important, this release of the system is being done under
an open source agreement, providing cost-free source-level access to the
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;
Sape Mullender wrote the new thread library.
Other new contributors include
Eric Van Hensbergen,
Computing Science Research Center
Murray Hill NJ
Copyright © 2000 Lucent Technologies Inc. All rights reserved.