ami@mirage.bellcore.com (Ami Litman) (02/03/88)
The DUNIX Distributed Operating System
Ami Litman
(ami@bellcore.com)
DUNIX is an operating system that integrates several
computers, connected by a packet switching network, into a
single UNIX* machine. As far as the users and their
software can tell, the system is a single large computer
running UNIX. This illusion is created by the cooperation
of the computers' kernels. The illusion is so complete,
that the kernels are able to migrate any process from one
computer to another without disturbing the behavior of the
process. The DUNIX kernel is procedure call oriented and
follows the principle of information hiding. The code that
implements a specific system call (e.g., open) does not
know whether the object in question (the file) is local or
remote. This uniformity makes the kernel small and easy
to maintain. The system behaves gracefully under subcom-
ponents' failures. Users who do not have objects (tty,
files, processes) in a given computer are not disturbed
when that computer crashes. The system administrator may
switch a disk from a sick computer to a healthy one, and
remount the disk under the original path-name. After the
switch, users may access files in that disk via the same
old names. DUNIX exhibits surprisingly high performance.
For a compilation benchmark, DUNIX is faster than 4.2 BSD,
even if in the DUNIX case all the files in question are
remote. A DUNIX installation consisting of five VAXes
connected by an Ethernet has been running in Bell Communi-
cations Research since September 1986. This system is on
the Internet network and speaks the TCP/IP protocols.
Researchers in Bellcore and other institutes are porting
DUNIX to Suns and Micro-VAXes. More information on DUNIX
may be found in:
. A. Litman, "DUNIX: A Distributed UNIX system",
Proceeding of the EUUG Conference, September
1986, pp. 23-31.
. A. Litman, "The DUNIX Distributed Operating System",
Operating Systems Review, January 1988.
Ami Litman
Bell Communications Research
435 South st.
Morristown, N.J. 07960
ami@bellcore.com
(201)829-4377