Browse Prior Art Database

Method to Provide a Dynamically Switchable Console for a UNIX Operating System

IP.com Disclosure Number: IPCOM000107554D
Original Publication Date: 1992-Mar-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 3 page(s) / 134K

Publishing Venue

IBM

Related People

Day, MN: AUTHOR

Abstract

It is useful to be able to dynamically switch the system console to another display to monitor system console messages. It is also useful when the designated console is broken or otherwise not available. Described is the mechanism to provide this function as implemented on AIX* v3.1.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 49% of the total text.

Method to Provide a Dynamically Switchable Console for a UNIX Operating System

       It is useful to be able to dynamically switch the system
console to another display to monitor system console messages.  It is
also useful when the designated console is broken or otherwise not
available.  Described is the mechanism to provide this function as
implemented on AIX* v3.1.

      Traditional UNIX** operating systems provided a statically
defined backup system console that was used if the init process
determined that the main console was not available or reachable.
This approach requires reconfiguring the system to designate an
alternate console, and does not support dynamically changing the
console output location when the system is in operation.

      This invention describes a mechanism that is used to
dynamically change the system console output device while the system
is in operation in order to view system console messages from other
than the display that was the console when the system was booted.
This mechanism also allows the primary (login) console to be moved to
a new terminal on the next system boot.  Moving the message and login
console to a pty is very important once X windows is started on the
console device.  This allows a pty (window) within the X environment
to take over the system console operation.  This invention also
allows the system console to be redirected to a file so that system
console messages can be saved into a file and viewed at another time.
This is especially useful for systems running unattended operations,
where they can be set up to run without a console device.

      The components in this invention are a console configuration
method, a starttty method, a console device driver, and three new
operator commands.  A chcons operator command allows the login
console to be changed to a different device when the system is
rebooted next, or when init is restarted at run level 2.  A swcons
operator command allows messages directed to the system console to be
redirected to another display device, or to a file.  It does not move
the system console that was used for login.  In the event that the
new target device for the message console becomes unavailable, the
console device driver automatically redirects all console message
output back to the login system console.  For example, if system
messages were directed to an active x window, or to a remote
terminal, and the x window was closed or the connection was lost with
the remote terminal, the driver would automatically redirect all
console messages back to the default or login system console device.
A final operator command, lscons, displays where the current message
console output is being redirected, what is the current login console
device, and where the login console device will be on the next system
boot or restart of init.

      The console configuration method, reassigns the console at boot
time if the current console device is c...