Norbert Lenz

From high availability and disaster recovery to business continuity solutions

We first provide an overview of the state-of-the-art architectures for continuous availability, briefly covering such traditional concepts as high-availability (HA) clustering on distributed platforms and on the mainframe. We explain how HA can be achieved in environments based on Sun Microsystems J2EE™, which differ from classical clustering approaches, and we discuss how disaster recovery DR) has become an extension of HA. The paper then presents aspects of service management, including the use and orchestration of process-based (ITIL®) systems management tasks within DR scenarios, where the key challenge is to ensure the right level of redundancy in the integration and service-oriented management of heterogeneous information technology landscapes.

Data management facilities of an operating system kernel

The paper describes the part of a general operating system Kernel supporting data management functions The operating system Kernel can be imbedded into microcode and viewed as an extended hardware interfaceFour Kernel instructions are defined to support data management They provide a powerful basis for the implementation of different kinds of access methods and file systems, including data base systems Advanced transaction processing concepts such as concurrency control, support of backout, commit and a variety of share options are included.

A knowledge-based system for MVS dump analysis

A new domain in software problem determination can be automated by means of this knowledge-based system. The system imitates a human problem solver by using the same tools and the same diagnostic approach as the experts use, including the processing of human-readable data. The application is fully integrated within the target Multiple Virtual Storage (MVS) operating system to ensure user acceptance. A large variety of knowledge is contained in the system, ranging from pattern-recognition knowledge to basic MVS knowledge and problem-solving strategies. The diagnostic approach is based on a model of software problem situations and on diagnostic reasoning methods adopted from the medical application domain. The goal of the project was to solve a significant part of the problem resolution process automatically, rather than to build yet another tool for use in software problem determination. This system is a first step to further automation in this area.

Single System Image for a Network of Processors

Support of distributed data processing, especially in a local area network, requires major modifications and extensions of existing operating system structures to provide,for example, automatic data set exchange, remote spooling, and terminal passthrough. Most of these facilities can be considered under the common goal of achieving a single system image for a network of processors.