Showing papers on "Data access published in 1986"

An object-oriented approach to multimedia databases

Abstract: This paper identifies data modelling and data access and sharing requirements which multimedia applications impose on a database system. It shows the capabilities of an object-based data model and indicates extensions which are needed to meet the data modelling aspects of these requirements. A logical implementation of the operations on the model is described. The model generalizes the notions of instantiation and generalization in the standard object-oriented paradigm, and augments it with the notions of aggregation and relationships which are specialized for a multimedia application environment. Objects may exist in aggregation hierarchies which provide the capability to integrate diverse types of multimedia information such as text, sound, bit-mapped images, and complex graphics drawings. Objects may also be linked through other user-defined relationships to capture such application functions as voice annotation and referencing of one document by another. Using this model, the semantics of aggregation and relationships in a multimedia application environment can be understood and efficiently supported by a database system.

Performance evaluation of the binary tree access mechanism in mimd type parallel computers.

Abstract: One of the most serious problems in a highly multiple parallel processing system involves memory access contention. In the hierarchically structured access mechanism, the number of simultaneous access paths increases with degree of parallelism. Consequently, it is considered as a configuration suited to a highly multiple parallel system. This paper uses a queue model to analyze the hierarchical routing bus (H-R bus), which is an access mechanism with a hierarchical structure. The paper further makes a quantitative evaluation of the locality in data access. Based on the derived theoretical expressions and measured results obtained by executing several test programs on the H-R bus-connected parallel computer, the H-R bus performance is evaluated. The results obtained in this paper are as follows: (1) Low external data access rates (i.e., external data access time/processing time) indicate that the H-R bus-connected multiprocessor system operates with high efficiency even under high multiplicity. (2) Under sufficient access locality, even high external data access rates do not unduly impair efficiency. Although the above properties have qualitatively been known before, this paper derives theoretical expressions for the properties, supported by experiments.

Apparatus and method for controlling access in a multi-cache data processing system

Abstract: Access to data stored within a main memory in a data processing system having a plurality of data processing units is restricted so that the data may not be corrupted by being accessed by more than one processing unit at any time.

External memory medium for storing program and computer system for external memory medium

Abstract: PURPOSE:To form small portable convenient external memory medium for storing a program by converting the program data, which have been read serially from the memory medium to parallel data and inputting the data into a computer. CONSTITUTION:External memory medium 10 for storing the program data has a data access circuit 13 provided with a generating function of writing and reading addresses of the data and a parallel/serial converting function of the data,and an interface which converts input/output data of a data access circuit 13 into parallel data and gives the same to a computer 20. Consequently, to transfer the data read from a memory 12 to the computer 20, the number of a terminal 14 installed at the memory medium 10 can be set to terminals, as small as five in number the mechanism constitution of a connector part goes to be simple and the reliability of the connecting condition of the two can be improved.

Collective control system for data access

Abstract: PURPOSE:To attain a data access regardless of existence in a main memory or an auxiliary memory by using a file control information table which is capa ble of collective controlling of data. CONSTITUTION:When the reference and replacement are given to a data set A by an application program, the reference is given to a file control information table 4 by a data collective processing means 3. Thus it is known that the data set A exists in an auxiliary memory means 2 and an access function of an auxiliary memory means of an operation system OS is called out. While it is known in the same way that a data set B eixsts in a main memory means 1. Thus it is possible to give an acess to a desired data set by a single procedure regardless of existence of the data set in a main memory or an auxiliary memory.

Data control system

Abstract: PURPOSE:To reduce the capacity of a main storage device because of residence, to secure a stable read-in/storage necessary time, and to read resident data at a high speed by giving resident attribute information to each data independently. CONSTITUTION:A parameter file 1 is stored with data, an operation parameter, and an attribute parameter; and an attribute giving part 2 stores an attribute and data which is processed as required in a data file 3 according to an operation parameter, and when a data processing system is started, a data developing part 4 reads data out of the data file 3 and stores only data whose attribute shows residence in a main storage device 5. A data access part 6 accesses the main storage device 5 or data file 3 according to an access indication from a data processing system.

Data management system

Abstract: PURPOSE:To detect that target data does not exist in a file with high speeds by retrieving an index part with a part of high-order keys and detecting a better the data belonging data key value exists in a data part or not. CONSTITUTION:A file is composed of an index part 1 and a data part, and each entry of the index 1 consists of parts k1-kn of high-order keys and address data a-c where the data having a key whose key value is the same as that of parts k1-kn exist. At the data access, in regard to whether the data equal to a part of the specified high-order key exist in the index 1 or not parts k1-kn of the high-order key are retrieved. If it exists, an address of a data part 2 is obtained from the entry of the index part 1 to read the block of the data part 2. thereafter, whether data having the specified key exist in the block or not is retrieved to read the data.

Distributed on-line digitized control architectures for process control

Abstract: A tremendous amount of investigations and realisations has been carried on for the last ten years in the domains of communication media and protocols, distributed database management, distributed operating systems and reliability resulting in significant progresses towards standardization. However, most of these results apply to on-line systems and relatively very little of this work is related to hard-real-time environments whereby specified bounds on processing delays are stringent and ranging from few millisecunds to few hundreds of millisecunds. Based on the ISO OSI-Reference Model analysis, rationale are presented for a reliable connectionless-mode, message due-date-dependant qualities of services and flexible conversation protocols above the transport layer. So as to support time-dependant transmission protocols, it is shown that the IEEE 802 Local Area Network standards must be enhanced in order to provide message transmission scheduling based on message due-dates. A task priority is defined as a function of both its static priority and its due-date. Data access serialization induces precedence constraints on task scheduling. Task resource allocation conflicts are solved though a unique task-priority-dependant resolution rule.

Diagnostic software development for TFTR

Abstract: The development of diagnostic software for the tokamak fusion test reactor (TFTR) machine is discussed. Key problems in the development process are the control of a large body of applications code and the provision of an environment that maximizes the productivity of the applications programmers. Control of the large body of code is accomplished through the use of a common method of software module specification, standard naming conventions, standard documentation, and automated utility programs to check the consistency of source code. The productivity of the applications programmers is enchanced by the presence of services providing graphics capabilities, terminal and user dialog management, data access, smoothing and compression, hardware device access and testing, and program execution tracing.