Abstract: A data retrieval engine accesses data streams (“tags”) from data sources. Each data stream preferably includes a plurality of values for a tag and a time each value was recorded. A user accesses the web server to request real-time performance data for a plurality of the tags. After authenticating the user, the data retrieval engine sends values for tags the user is authorized to view to the web server, for delivery to the browser. The data retrieval engine tracks which values were sent to the web server for each user and when. When the data retrieval engine receives a request for a specific user, only data not previously provided to the web server for that user is provided for the current request. In this manner, the user does not miss any events, and is provided substantially in real time with a complete set of data for requested tags.

Abstract: A data processing system includes at least one processor and data storage containing an array including N records having value-ordered entries. To find an entry matching a search value, W, a number of records to be searched, is set equal to N, and each of the W records is assigned to either a first set or a second set, where the first set includes X/2 of the W records and X is a smallest power of 2 equal to or greater than W. In response to a determination that the search value precedes the first record within the second set, a binary search of the first set of records is performed to identify a record including an matching entry. If the first entry of the first record within the second set matches the search value, the first record within the second set is identified.

Abstract: A method and data processing system for emulating a program are disclosed. According to the present invention, the data processing system runs under a first operating system and emulates the execution of a program under a second operating system within a second data processing system. The data processing system includes a memory which stores at least a portion of the first operating system and an emulator comprising a plurality of routines which each emulate an instruction utilized by the first operating system. The memory further includes a simulated mass storage data area which stores at least a portion of the program and a simulated main memory data area. The data processing system further includes a processor which executes instructions within the program under the first operating system by emulation. According to the present invention, the emulator accesses instructions of the program directly from the simulated mass storage data area to minimize emulation overhead.

Abstract: A method and data processing system for emulating a program are disclosed. According to the present invention, the data processing system runs under a first operating system and emulates the execution of a program under a second operating system within a second data processing system. The data processing system includes a memory which stores at least a portion of the first operating system and an emulator comprising a plurality of routines which each emulate an instruction utilized by the first operating system. The memory further includes a simulated mass storage data area which stores at least a portion of the program and a simulated main memory data area. The data processing system further includes a processor which executes instructions within the program under the first operating system by emulation. According to the present invention, the emulator accesses instructions of the program directly from the simulated mass storage data area to minimize emulation overhead.

Abstract: In a processor having a real address space larger than its virtual address space, all of the physical memory is addressed by using a separate prefix register associated with each of the address registers to hold both a high-order address portion and a control bit specifying whether the address is to be translated or used as a direct real address.