International Business Machines Corporation

Charles William Lickel

Kenneth Wayne Boyd

Kenneth Fairclough Day, Iii

John Jay Wolfgang

Harry G Familetti

Judith Helen Bank

Balakrishna Raghavendra Iyer

Vahit Hakan Hacigumus

Dante Aligheri Aubert

Mark E Swallow

Ross A Mauri

Janis L Coltin

Provided are a method, system, and article of manufacture, wherein a controller receives a request from one of a plurality of hosts. The controller determines whether a primary storage control unit coupled to the controller is operational. A response is generated by accessing the primary storage control unit, in response to determining that the primary storage control unit is operational. The response is generated by accessing a secondary storage control unit, in response to determining that the primary storage control unit is not operational, wherein data is replicated synchronously from the primary storage control unit to the secondary storage control unit.

Redirection of storage access requests based on determining whether write caching is enabled

Redirection of storage access requests

A method and system for providing a database as a is disclosed. In a first aspect, the method comprises the steps of accessing the database over a public network by a browser without downloading software. The method further includes controlling access to the database on an agreed-upon schedule. In a second aspect, a database service for use on a public network is disclosed. The database service comprises a presentation layer, the presentation layer including a browser, a web server coupled to the public network and a web application platform coupled to the web server. The database includes an application layer comprising a user interface (UI) application. The UI application is executed on the web application platform and is capable of communicating with the browser through a standard program code. Finally, the database service includes a database management layer. The database management layer includes at least one database which communicates with the UI application. Accordingly, a database can be managed centrally while resources of the database can be consumed individually and globally.

Method and system for utilizing a database as a service

An in-storage table pair structure is disclosed which extends to the user of the data processing system the internal structures of a component of the operating system. The table pair structure includes pairs of tables that are pointed to by a table pair pointer. A table pair pointer is a double word of virtual storage in which the first word is the address of a user-defined table and the second word is the address of a developer-supplied table. Both tables form a table pair. The table pairs permit functional routines (IETDFs) to reference data in both developer-supplied tables as well as user-defined tables in order to tailor a component of the operating system. The IETDF locates a particular table, or set of tables, by first referencing a global control block which contains addresses of two router control blocks. One is the developer-supplied router control block which contains table pair pointers to all developer-supplied tables that are used by the IETDFs and the other is the user-defined router control block which contains the table pair pointers for all user-defined tables that are used by all IETDFs. The user, through entries in the user-defined table, can add unique table entries that define new functions and override developer-supplied table entries, without actually making changes directly to the operating system or providing exit routines, by utilizing the same table entry identifier as is used to identify the corresponding entry in the developer-supplied table.

Method of tailoring an operating system

An apparatus and method employs dual checkpoint data sets for communicating system status. A journal of changed data is implemented to reduce I/O to a subsystem's shared data area on a non-volatile shared storage device. The journal provides for an increase in the amount of time that a processor may have access to the shared data area. Also, two versions of the data area are implemented in order to insure the integrity of the continuously updated data area. The two versions flip-flop depending upon which one has the most recent updates. That is, the version that has the most recent updates becomes the to-be-read-from data area and is read by the processor that currently has access to the shared data area during this series of I/O operations. The other version becomes the to-be-written-to data area and is written to by the processor that currently has access to the data area in order to update the to-be-written-to version to the current level. The to-be-written-to version then becomes the to-be-read-from version during the next series of I/O operations.

Multiprocessor system for updating status information through

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Tucson, AZ, United States of America

Charles William Lickel