Browse Prior Art Database

Grouping User Logons to a Multitasking Address Space

IP.com Disclosure Number: IPCOM000117936D
Original Publication Date: 1996-Jul-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 6 page(s) / 167K

Publishing Venue

IBM

Related People

Ault, DF: AUTHOR [+3]

Abstract

Disclosed is a method for clustering mutiple user connections to an operating system within a single address space. The processes that manage a users terminal connection to a host can be combined and executed in a single address space to conserve system resources.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 37% of the total text.

Grouping User Logons to a Multitasking Address Space

      Disclosed is a method for clustering mutiple user connections
to an operating system within a single address space.  The processes
that manage a users terminal connection to a host can be combined and
executed in a single address space to conserve system resources.

      Typical UNIX* systems support a number of functions which allow
users on workstations to connect to a host mainframe to request work.
These requests typically create multiple processes (address spaces)
to manage the terminal connection, in addition to a process to do the
actual work.  For example, the rlogin function on UNIX systems will
typically create a rlogind process to manage the inbound TCP/IP
connection (socket), a shell process to manage user requests and then
additional processes to execute shell commands.  A user that is
connected via rlogin will consume two processes even when no work is
being done.  Fig. 1 shows the layout of processes for a single rlogin
request.  To make the situation worse, a typical UNIX user will login
multiple times.  A user that typically creates 5 shells will consume
10 processes.

      In OpenEdition MVS, the initial shell support from TSO allowed
the user to create multiple shells that resided in a single address
space.  A problem with this method was that it had some non-UNIX
characteristics and performance problems.  As users switch to the
typical UNIX connections like rlogin through a TCP/IP socket, it will
create an unacceptable burden on the MVS system because of the
excessive number of address spaces needed to support a single user.

      A solution to this problem builds on existing support in
OpenEdition MVS which allows the application to create multiple POSIX
processes in a single address space.  The main function in this
solution is providing a mechanism to cluster multiple independent
requests for a new process, for the same user, to a single address
space.  This can best be explained with an example of how it will
work before and after this invention is used.

      Old Method

      Fig. 1 shows how a user connects from a workstation to a
mainframe UNIX system using a function called rlogin:
  1.  A user on a workstation enters the rlogin command, identifying
       the system to which they wish to connect.
  2.  TCP/IP processes this request and opens a socket connection to
       the specified host.
  3.  The host typically has a function called an INET daemon or
INETD
       for short.  INETD listens for these socket connections.  When
a
       connection is detected for rlogin, INETD does a fork and exec
of
       a rlogin daemon (rlogind).  After this the INETD goes back
into
       the select to wait for further connection requests.
  4.  The rlogind is the process that behaves as the master side of a
       pseudo tty.  This means that the rlogind is responsible for
 ...