International Business Machines Corporation

Ann M Shepherd

Steven S Shultz

Stephen E Record

Valery I Garger

The preferred embodiment of the present invention provides a method and apparatus for storing and accessing data. The preferred embodiment hybrid tree-array database provides the ability to perform fast searching using tree database search techniques and the ability to search all user data fields using array search techniques. In particular, fast key searching as a typical tree database and sequential array searching of all data fields as a typical array database are provided in a single database, without requiring the user data be duplicated and stored in two separate databases. Thus, the preferred embodiment provides searching flexibility without the excessive storage requirements and complexity inherent in managing separate array and tree databases. The preferred embodiment also provides the advantage of allowing individual users of the database to search the data using either tree or array search techniques without requiring any detailed knowledge of the dual nature of the hybrid tree-array database.

Hybrid tree array data structure and method

A computer operating system manages events defined by an application program or another part of the operating system. Each event definition includes one or more attributes of the event which controls some operating system responses to an occurrence of the event. After an occurrence of a defined event, an application program or another part of the operating system signals an event manager. The event manager reads the corresponding event definition to determine a mode of operating the signaller of the event or a process associated with the event signaller. The operating modes include a synchronous mode whereby the event signaller or the associated process should suspend processing until the event is handled, and an asynchronous mode whereby the event signaller or associated processor can continue processing while the event is being handled. After reading the event definition, the event manager advises the event signaller whether to proceed synchronously or asynchonously. After the event is handled, a suspended event signaller is restarted. The event definition can be updated dynamically.

Asynchronous or synchronous operation of event signaller by event

A computer operating system manages events of interest to a plurality of event handlers within respective programs. The event handlers are arranged in a sequence for the purpose of receiving sequential notification of an occurrence of the event. When the event occurs, the first event handler in the sequence is notified, and it then handles the event. Then, the first event handler determines if the second event handler in the sequence should be notified of the event. If so, the second event handler in the sequence receives the event notification, handles the event, and then determines if the third event handler in the sequence should be notified. In this manner, the event notification can be propagated from event handler to event handler in the sequence, but any event handler in the sequence which receives the notification can block subsequent propagation of the event notification. This technique saves processing time in situations where some or all of the event handlers in the sequence (after the first event handler) may not benefit from the event notification; in such a case, the event notification is not propagated to them.

Notification of event handlers in broadcast or propagation mode by event

A computer operating system manages events. An application program or another part of the operating system defines an event monitor to monitor one or more types of events on its behalf. When each of the monitored events occurs, the event monitor is signalled and stores the event signal. Under certain conditions, the event monitor can notify an event handler, and the event handler can access the stored event signals. The event monitor can be defined and established dynamically, i.e. throughout operation of the computer without stopping or relinking the computer system. In the absence of an event monitor which is interested in an event, signals of the event are nevertheless stored. When an interested event monitor is subsequently established, the previously stored event signals are transferred to the interested event monitor. Thus, the event handler has the benefit of previous event signals. The event can be a trace event, and the event handler associated with each event monitor can receive and handle the trace events in real time.

Dynamically established event monitors in event management services of a

A computer operating system manages different types of events. An application program or another part of the operating system defines an event monitor to monitor one or more types of events. The definition also specifies a combination of occurrences of the one or more types of events required to satisfy the event monitor. When each of the monitored events occurs, the event monitor is signalled and stores the event signal. When the event monitor has stored signals which satisfy the event monitor, the event monitor can notify an event handler (pursuant to a standing or subsequent inquiry by the event handler). Then, the event handler can access the stored event signals.

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Endwell, NY, United States of America

Ann M Shepherd