Data processing: software development – installation – and managem – Software upgrading or updating
Reexamination Certificate
1999-07-16
2004-02-24
Ingberg, Todd (Department: 2124)
Data processing: software development, installation, and managem
Software upgrading or updating
Reexamination Certificate
active
06698017
ABSTRACT:
FIELD
The present invention relates generally to software migration and, more particularly, to the migration of control over a processing element from an original software system to a replacement software system.
BACKGROUND
Performing a software upgrade on computer hardware which is providing services to users or other computer devices presents significant challenges to maintaining the availability of such services during the upgrade. This is particularly the case when the services of the computer hardware are provided at least in part at the direction of the software being replaced in the upgrade. The process of upgrading or replacing the software that controls the computer hardware is often referred to as a software migration and involves replacing the original software with replacement software. During a conventional software migration, the services influenced by the operation of the original software are typically unavailable until the software migration is complete. Such conventional techniques can result in significant periods during which time the computer hardware is unable to provide services controlled by the software being replaced. This problem can become more pronounced in circumstances where there is a need for reliable quality of service, such as in networks and other systems where a high degree of availability may be required for certain services.
A known solution to such software migration has been to replace the computer hardware with new hardware programmed to provide the new or modified functionality or performance desired. This technique provides a rather crude approach to modifying the services provided by the computer hardware and results in undesirable and extended outages when the computer hardware is unable to support the services it is expected to provide to users, systems or other devices. Such extended outages can be disruptive to both the systems and the users that rely on the operation of the computer hardware. This solution also requires a manual replacement of all or portions of the computer hardware.
A common approach in the telecommunications industry for reducing the impact of a software migration on the services supported by the computer hardware involves providing duplicate computer hardware. In this latter case, control over available services is passed from the original computer hardware and software to the duplicate computer hardware with replacement software. This approach results in redundant computer hardware sitting idle or underutilized during normal operations when no software migration is taking place, as well as unnecessary complexity in the arrangement and configuration of the original and duplicated computer hardware.
Therefore, it would be desirable to develop an improved mechanism for software migration, which makes more efficient use of installed computer hardware while minimizing the impact on the availability of services during such software migration.
SUMMARY OF THE INVENTION
The above and related desires are addressed in the present invention by providing a novel and nonobvious method, apparatus, computer-readable program and system for migrating control of an active processing element from an in-service original software system to a replacement software system. In this specification, the term “processing element” refers to a processor (or processors) having, or in communication with, sufficient memory to store both the in-service original software system, the replacement software system and additional software supporting the transfer of control from the original software system to the replacement software system. When the processing element is “active”, it is able to provide services to users or other computer hardware under the direction of a software system. In general, the term “software system” (original, replacement or otherwise) refers to one or more software components programmed to provide one or more services. Such “services” may be any functionality that is useful to the operation of the software system itself or to the operation of other associated computer hardware or software. Services are primarily externally visible to, or support external benefits visible to, users, systems or other computer hardware or other services. “In-service” is used in this specification to mean that the original software system has control over the processing element so as to make available via the processing element the services for which the original software system is programmed to provide. In addition, in the remainder of the specification which follows, the term “software migration” refers to a process of transferring control over the active processing element from the original software system to the replacement software system.
In accordance with one aspect of the invention, a method of performing a software migration is provided. In this method, the replacement software system is configured in memory associated with the active processing element and made ready to take control of the active processing element while the in-service original software system controls the active processing element. In order to make the replacement software system ready to take control, state information from the original software system is communicated to the replacement software system. Once the replacement software is installed and ready to take control of the active processing element, control over the active processing element is transferred from the original software system to the replacement software system. Performing a software migration on the active processing element while the original software system controls the active processing element removes the need for having a duplicate processing element to support the migration while substantially maintaining the availability of services on the processing element. By simplifying the hardware requirements and localizing much of the software migration to within the domain of the active processing element, the number and severity of service outages on the processing element arising during the software migration are also reduced. The term “service outage” refers here to periods when services, provided by a software system via the active processing element, are unavailable.
Although the present invention can be applied to a single processor environment, it also may be applied in a multi-processor (or multi-controller) environment. In fact, when the present invention is applied to a computer system with one or more spare processing elements, processor sparing can be maintained throughout the software migration. In conventional environments, processor sparing or duplication is implemented to provide equipment protection, or in other words, to protect the operation of computer system in the event a running processor, or other computer hardware associated with the processor, fails. In such conventional environments, equipment protection for a processing element is lost during software migration while the spare or duplicate processing element is used in the software migration. Thus, the present invention offers a more robust migration solution which is also applicable to processor spared systems.
In a preferred embodiment, the replacement software system is configured with provisioning information associated with a hardware and software configuration for the active processing element, and dynamic state information for the replacement software system is synchronized with dynamic state information for the original software system. In this specification, the term “provisioning information” refers to persistent state and configuration information for the software system controlling the active processing element. Provisioning information is meant to survive a power down or reset of the active processing element. The term “dynamic state information” refers to hardware and software state information for the active processing element which varies with time. In the case of the original software system, the dynamic state information includes the state of active services associated with the original software
Adamovits Peter Joseph
Berube Louis Pierre
Dysart Keith Clifford
Ingberg Todd
Nortel Networks Limited
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