Showing papers on "Data access published in 1983"

The Architecture of an Integrated Local Network

Abstract: The DOMAIN system is an architecture for networks of personal workstations and servers which creates an integrated distributed computing environment. Its distinctive features include: a network-wide file system of objects addressed by unique identifiers (UID's); the abstraction of a single level store for transparently accessing all objects, regardless of their location in the network; and a network-wide hierarchical name space. The implementations of these facilities exhibit several interesting approaches to layering the system software. In addition to network transparent data access, interprocess communication is provided as a basis for constructing distributed applications; as a result, we have some experience to guide the choice between these two alternative implementation techniques. Networks utilizing this architecture have been Operational for almost three years; some experience with it and lessons derived from that experience are presented, as are some performance data.

Active Databases as a Paradigm for Enhanced Computing Environments

Abstract: : Active databases emphasize the notion that a body of information is dynamic and should respond intelligently and in non-trivial ways to the user. It provides a paradigm for research and development which combines aspects of both databases and artificial intelligence technologies. A prototype system has shown the viability of this approach. The author focuses on the following database issues : (1) Descriptions are used as semantic templates for associatively accessing and manipulating data objects; (2) Dynamic views minimize the typical distinctions between queries and retrievals, and between views and real data, and thereby increase the perceived immediacy of the user interface; and (3) Constraint Equations are developed as a declarative representation for semantic constraints. The uniform approach they provide for expressing database integrity, consistency, and more general semantics derives its power from the rule-based framework of recent A.I. expert systems. The efficiency of constraint maintenance also is considered. Lastly, (4) The notion of binding time of data associations and reference is discussed relative to both the choice of data model and to the method of data access. (Author)

McIDAS III: A Modern Interactive Data Access and Analysis System

Abstract: A powerful facility for meteorological analysis called the Man Computer Interactive Data Access System (McIDAS) was designed and implemented in the early 1970's at the Space Science and Engineering Center of the University of Wisconsin-Madison. Hardware and software experience gained via extensive use of that facility and its derivatives have led to a newer implementation of McIDAS on a larger computer with significant enhancements to the supporting McIDAS software. McIDAS allows remote and local access to a wide range of data from satellites and conventional observations, time lapse displays of imagery data, overlaid graphics, and current and past meteorological data. Available software allows one to perform analysis of a wide range of digital images as well as temperature and moisture sounding data obtained from satellites. McIDAS can generate multicolor composites of conventional and satellite weather data, radar and forecast data in a wide variety of two- and three-dimensional displays as well as time lapse movies of these analyses. These and other capabilities are described in this paper.

Abstraction mechanisms for database programming

Abstract: Databases contain vast amounts of highly related data accessed by programs of considerable size and complexity. Therefore, database programming has a particular need for high level constructs that abstract from details of data access, data manipulation, and data control. The paper investigates the suitability of several well-known abstraction mechanisms for database programming (e.g., control abstraction and functional abstraction). In addition, it presents some new abstraction mechanisms (access abstraction and transactional abstraction) particularly designed to manage typical database problems like integrity and concurrency control.

Natural language access to data bases: interpreting update requests

Abstract: For natural language data base systems to operate effectively in practical domains, they must have the capabilities required by real applications. One such capability is understanding and performing update requests. The processing of natural language updates raises problems not encountered in the processing of queries. These difficulties stem from the fact that the user will naturally phrase requests with respect to his conception of the domain, which may be a considerable simplification of the actual underlying data base structure. Updates that are meaningful and unambiguous from the user's standpoint may not translate into reasonable changes to the underlying data base. Update requests may be impossible (cannot be performed in any way), ambiguous (can be performed in several ways), or pathological (can be performed only in ways that cause undesirable side effects).Drawing on work in linguistics and philosophy of language, we have developed a domain-transparent approach to identifying and performing "reasonable" changes in response to a user's update request, using only knowledge sources typically present in existing data base systems. A simple notion of "user model" and explanation with respect to the user's state of knowledge are central to the design. This paper describes a prototype system PIQUE (Program for Interpretation of Query/Update in English), which implements this approach.

Lower bounds on the time of probabilistic on-line simulations

Abstract: We study probabilistic on-line simulators for several machine models (or memory structures). The simulators have a more constrained access to data than the virtual machines, but are allowed to use probabilistic means to improve average access time. We show that in many cases coin tosses can not make up for inadequate access.

Lower Bounds on the Time of Probabilistic On-Line Simulations (Preliminary Version)

Abstract: We study probabilistic on-line simulators for several machine models (or memory structures). The simulators have a more constrained access to data than the virtual machines, but are allowed to use probabilistic means to improve average access time. We show that in many cases coin tosses can not make up for inadequate access.

Data management support for selected climate data sets using the climate data access system

Abstract: The functional capabilities of the Goddard Space Flight Center (GSFC) Climate Data Access System (CDAS), an interactive data storage and retrieval system, and the archival data sets which this system manages are discussed. The CDAS manages several climate-related data sets, such as the First Global Atmospheric Research Program (GARP) Global Experiment (FGGE) Level 2-b and Level 3-a data tapes. CDAS data management support consists of three basic functions: (1) an inventory capability which allows users to search or update a disk-resident inventory describing the contents of each tape in a data set, (2) a capability to depict graphically the spatial coverage of a tape in a data set, and (3) a data set selection capability which allows users to extract portions of a data set using criteria such as time, location, and data source/parameter and output the data to tape, user terminal, or system printer. This report includes figures that illustrate menu displays and output listings for each CDAS function.

Control system for associative buffer memory

Abstract: PURPOSE:To shorten the time of data access and to improve a processing speed by storing data having high stack access frequencies in an associative buffer memory and storing data having low stack access frequencies in a stack. CONSTITUTION:In a figure, 5 is a detection part and 6 is a control part. The detection part 5 detects and outputs data having a minimum stack access frequency stored in an access frequency memory part 4 among data corresponding to associated addresses generated by a write address generation part 3 among data stored in a data memory part 2. Under the control of the control part 6, the stack access frequency of data obtained by accessing the stack newly is compared with the frequency of the data detected by the detection part 5 and when the frequency detected by the detection part 5 is less, the data and its access frequency are erased from the memory part 2 and access frequency memory part 4 to write the newly accessed data and its frequency therein respectively.

Data access system for disk file

Abstract: PURPOSE:To improve data processing efficiency by providing plural record buffer registers, and starting retrieval at data stored later in response to a data access request and storing accessed data in the register again. CONSTITUTION:In the plural record buffer registers, data equivalent to data to be stored in a disk file for storing numbers of data, are stored together with additional disk addresses. In response to the data access request, the retrieval is started at data stored later to access corresponding data, and the accessed data is re-stored in the record buffer registers as up-to-data data together with additional disk addresses. When the corresponding data is not found, data in the disk file is accessed and the accessed data is stored in the record register as up-to- data data together with the additional disk addresses. Thus, mean access time is shortened to improve the data processing efficiency.

Local Network Cryptosystem Architecture: Access Control

Abstract: A mechanism which uses keyed verification sequences at the link layer of protocol to control access to data transport facilities of a local area network will be described.

Data access device

Abstract: PURPOSE:To speed access to data by freely varying the response setting time of each storage element CONSTITUTION:When the storage parts 12-14 of external storage devices 6-8 are accessed through the CPU1 of a central arithmetic part 19, respose signal generation parts 9-11 of the storage parts 12-14 send response signals to the CPU1 at set time Then, data read out of the storage parts 12-14 are inputted to the arithmetic part 19 and checked by a diagnosing circuit 2; when no error is found, they are stored in a storage device 3 If an error is found, on the other hand, the set time of a corresponding generation part is varied through the CPU1 and said operation is retried Writing is the same and data access is speeded without the need to fix the response time to the longest time for safety

An integrated system for data acquisition, archiving and analysis in eta-beta ii

Abstract: The paper describes the conceptual design of a new system, built around the functional blocks of data acquisition and archiving. Various kinds of data are recognized, on which specific functions are to be performed: shot setting parameters, shot attributes, raw data, intermediate results and also software module names. In order to adequately describe an intrinsicaly dynamic experiment the concept of experiment model is introduced, with a hierarchical structure reflecting logical and physical relationships. The interactions between blocks and with the environment are standardized by the definition of interface data structures. An integrated archiving system for raw data, intermediate results and related computing procedures is described, whose main goal is to simplify and standardize data access and analysis.

Storage device for disc data

Abstract: PURPOSE:To detect the defective state of storage media for disc data easily and to improve preliminary maintenance capacity by providing means for storing pseudo times of read errors and pseudo times of data access in track units. CONSTITUTION:An adapter 1 of a storage device for disc data is connected to a data control device by means of a data path 3 and a command path 4. A logic part 14 for receiving commands receives the command code for setting storage addresses and a command decoder 12 supplies the data that the data control device puts on the path 3 as data storage address into a memory 11. Also, the decoder receives the command code for setting the stored data and stores the contents of the data stored in a data register 18 in the memory 11. The decoder receives the command code for taking in of the stored data, reads out the stored data of the memory 11 and stores the same in the register 18. In succession, the decoder 12 acts so as to transfer the contents of the data in the register 18 into a buffer logic part 13 for transmission and reception of data by taking a timing, and to put the same on the path 3. Thus, the data control device stores and reads out optional data.