UNIX SVR4
COSC513
Zhaohui Chen
Jiefei Huang
UNIX SVR4
• UNIX system V release 4 is a major new
release of the UNIX operating system,
developed by AT&T and Sun
microsystems
• Goals : standardization of the UNIX
system and introduction of new
technology
Standardization of the UNIX system
• Previous operating systems are open systems.
• SVR4 is developed to provide a uniform
platform for commercial
• It combines features from SVR3 , BSD4.3 ,
SunOS and Microsoft XENIX system V.
Introduction of new technology
• Extends networking capabilities
• Improves system administration and
maintenance
• Further internationalizes the UNIX
system
SVR4 new features
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Operating system enhancements
File system enhancements
Networking
System administration and maintenance
Real-time support
SVR4 new features
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Character user interface
Graphical user interface
Internationalization
C language
Extended terminal interface
Operating system enhancements
SVR4 uses a virtual memory
architecture based on SunOS which
has efficient use of system’s main
memory and capability to execute
very large programs.
Additional benefits
Mapped files : allows a file to be
mapped explicitly into the address
space of a user program. This
makes user program easier to write
and allows programs to execute
more efficiently.
File system enhancements
Virtual file system : allows several
different file system types to coexist
on the same system.
rfs (BSD based)
nfs (SunOS based)
s5 (earlier UNIX release based)
System administration and maintenance
• Software installation and configuration
management tools : allows an
administrator easy access to information
• System administration menus : allows a
user to administer a UNIX system
without knowledge of UNIX system
commands.
Real-time processing
• User-controlled process scheduler :
kernel code that determines what
program will run, when, and for how
long.
• High-resolution timers : gives
microsecond resolution, good for
applications deal with very short time
intervals.
Character-based user interface
• Framed access command environment :
an interface allows a user to see the UNIX
system through frames containing menus
and forms.
• SVR4 enhanced FACE to be more
consistent and adding applications to
FACE has been made easier.
Graphical user interface
• OPEN LOOK graphical user interface :
defines a standard for the ‘look and feel’
of the GUI applications.
• XWIN graphical windowing system :
gives the user the ability to create
multiple windows on a single display,with
each window running different
applications.
Internationalization
• Support for multiple international code
sets and character
• Translate system messages to the user’s
native language
• Support the national conventions used to
communicate
C language
• Enhanced c packages : C programming
language utilities(CPLU), Advanced
programming utilities(APU), C
programmer productivity tools(CPPT).
• New features : dynamic linking
dynamic tables . . .
Extended terminal interface
• Standard programming interface
provided in release 4 for character screen
management and character operations.
• Consists of 3 libraries
• Provides C subroutines for creating
forms , menus, form editing
functions,panels
Networking on UNIX SVR4
Networking on UNIX SVR4
• UNIX SVR4 merges the networking
facilities of UNIX SVR3, BSD4.2 and 4.3,
and SunOS.
• It also introduces new networking
routines .
From UNIX SVR3
• Transport level interface (TLI)
• Remote file sharing mechanism(RFS)
• Streams
From BSD 4.2 and 4.3
• TCP/IP protocols
• Sockets
• Inetd facility
From SunOS
• Network file system (NFS)
New facilities in SVR4
• The network selection mechanism
• Name-to-address mapping
Transport level interface (TLI)
TLI defines an interface between
applications and transport level
network protocols, relieving user
programs of the need to know the
protocol characteristics.
Remote file sharing (RFS)
It provides transparent access to
remote files and devices .
Stream
• A framework for developing network
protocols
• It defines standard interfaces that allow
networking architectures and high-level
protocols to be independent of underlying
protocols,drivers,and media.
TCP/IP
UNIX system V release 4 supports
TCP/IP and supports networking
among systems of different types.
Sockets
• Sockets is a networking interface widely
used in BSD systems which defines how a
process accesses the services of a
protocol.
• In SVR4, sockets is provided in a library
so that BSD applications that use sockets
can migrate easily to SVR4.
Inted
• In release 4 , UNIX system V supports
inetd, a port monitor that waits for
service requests from computers on a
TCP/IP network.
• When a connection request arrives, inted
spawns the server process and passes the
network connection to it.
Network file system (NFS)
• A standard for sharing files between
different machines, operating systems in
a network
• Users can get directly to the files they
want without knowing the network
address of the date.
Network selection
• New features in UNIX SVR4
• it allows network applications to choose
the network over which they will
communicate.
• If an application fails to connect with its
first choice, it can select different
networks until it finds one that meets its
requirements and allows the connection.
Network selection
With Network selection, an application
does not need a network selection
embedded in its code. This allows the
application to run without modification
on different systems that support
different networks.
Name-to-address mapping
Name-to-address mapping is a
mechanism that allows network
clients to determine the addresses
of servers on a network in a
network independent manner.
Name-to-address mapping
• This mechanism makes it possible for
clients to reach a server, even if the
address on which the server is listening
should change.
• It also allows a client to reach a server
over different networks.
References
• AT&T,UNIX SYSTEM V/386 RELEASE 4 product overview
and master index, Unix press 1991
• Michael Padovana, Networking applications on UNIX system
V release 4, Prentice Hall 1993
• M Santifaller, TCP/IP and NFS:internetworking in a UNIX
environment,Addison-Wesley 1994
• Mark G Sobell,Unix system V:a practical guide, AddisonWesley 1995
• http://www.stokely.com/unix.sysam.resources/index.html
• http://darkwing.uoregon.edu/~hak/unix.html