Browse Prior Art Database

Power Fail Notification And Controlled Shut Down of Computer Systems

IP.com Disclosure Number: IPCOM000120604D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 3 page(s) / 124K

Publishing Venue

IBM

Related People

Klaasen, JA: AUTHOR [+2]

Abstract

Described is a method to allow a computer system to survive short power outages, to provide power failure notification and to enter a controlled shut down for longer outages. The concept is unique in that it provides an interface to enable software to monitor the state of the system. This enables the software to appropriately handle errors without outside intervention.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Power Fail Notification And Controlled Shut Down of Computer Systems

      Described is a method to allow a computer system to
survive short power outages, to provide power failure notification
and to enter a controlled shut down for longer outages.  The concept
is unique in that it provides an interface to enable software to
monitor the state of the system. This enables the software to
appropriately handle errors without outside intervention.

      In prior art -*-, a computer system may employ an alternate
power source to enable the system to continue operation during a
power failure.  However, in certain applications, such as in
industrial applications where the system is unattended, it is
essential to have the ability to monitor the software and to be able
to handle errors appropriately without outside intervention.  The
concept described herein provides a method of notifying the software
application program of the power failure and to prepare for a system
shut-down. Also, the concept provides a means of removing the
alternate power source to completely disable the system until primary
power returns.

      The system utilizes a read-only memory (ROM) control program
that polls the availability of the primary power. When power is lost,
a primary power loss flag from the alternate power source, usually a
battery-backed storage unit, is set to indicate a failure.  This flag
in the alternate source can be interrogated later.  The control
program periodically monitors the state of the power source during a
momentary power failure, commonly known as the glitch period.  If
primary power is restored during the glitch period, then the control
program continues normal execution.  This glitch protection aspect is
programmable. It removes needless concern about temporary power
losses while maintaining power and uninterrupted system operation. To
notify the user of a temporary power loss, a hexadecimal display is
used.  A keyswitch is provided that enables and disables all glitch
and shut-down support.  If the keyswitch is in maintenance mode, then
no glitch or shut-down protection is provided.  This is primarily a
service feature.

      The flow chart in block diagram on the following page shows how
the primary po...