Showing papers on "Interface (computing) published in 1978"

SIFT: Design and analysis of a fault-tolerant computer for aircraft control

Abstract: SIFT (Software Implemented Fault Tolerance) is an ultrareliable computer for critical aircraft control applications that achieves fault tolerance by the replication of tasks among processing units. The main processing units are off-the-shelf minicomputers, with standard microcomputers serving as the interface to the I/O system. Fault isolation is achieved by using a specially designed redundant bus system to interconnect the proeessing units. Error detection and analysis and system reconfiguration are performed by software. Iterative tasks are redundantly executed, and the results of each iteration are voted upon before being used. Thus, any single failure in a processing unit or bus can be tolerated with triplication of tasks, and subsequent failures can be tolerated after reconfiguration. Independent execution by separate processors means that the processors need only be loosely synchronized, and a novel fault-tolerant synchronization method is described. The SIFT software is highly structured and is formally specified using the SRI-developed SPECIAL language. The correctness of SIFT is to be proved using a hierarchy of formal models. A Markov model is used both to analyze the reliability of the system and to serve as the formal requirement for the SIFT design. Axioms are given to characterize the high-level behavior of the system, from which a correctness statement has been proved. An engineering test version of SIFT is currently being built.

Interface between a microprocessor chip and peripheral subsystems

Abstract: An interface between a microprocessor chip and input/output, and memory modules. The interface uses a single, bidirectional bus comprised of a number of lines which is less than the number necessary to carry a complete address word or a full width data word. Information transfer is effected by transferring information in small portions utilizing two or more interface clock cycles. An encoded control specification placed on the bus during the first cycle of information transfer specifies the type of access, the direction of transfer, and the length (number of bytes) of data to be moved. Only two additional simplex lines, one from the microprocessor and the other to the microprocessor are needed to complete the basic interface.

Security system for data processing

Abstract: A data processing security system employs a secure enclosure, such as a vault, for all cryptographic processes, and the maintenance of digital information in storage outside of the enclosure in encrypted form and when not in use by the host computer system, where the information is used in plain text form and which communicates with the enclosed encryption system by a standard interface.

Automated validation of a communications protocol: the CCITT X.21 recommendation

Abstract: The call establishment procedure of the X.21 interface recommended by the International Telegraph and Telephone Consultative Committee (CCITT) has been validated as a test of a recently developed theory and of an implemented system for automated communications protocol validation. The test demonstrated the applicability of the validation technique and identified a number of points where the interface state diagram does not completely define the interface behavior.

Multiprocessor numerical control system

Abstract: A numerical control system includes a main processor which performs such functions as interpolation and outputting of motion command signals to the servomechanisms on a machine tool. A separate programmable interface processor connects to the main processor bus structure and it operates as a programmable controller to control the discrete digital I/O devices associated with the machine tool. A third processor couples through a serial data link with the main processor and it operates to service peripheral I/O devices associated with the front control panel on the numerical control system.

Computer driven control system for a numerically controlled machine tool

Abstract: A control system for a numerically controlled (NC) machine tool which includes a direct access, time sharing, general purpose host computer located remotely from the location of the machine tool, is provided with a dedicated microprocessor located proximate the machine tool. The dedicated microprocessor has a storage memory in which at least one control tape or program may be stored. The microprocessor is operatively connected to the general purpose computer through a telecommunication (telephone) data set. The dedicated microprocessor in turn is connected to the machine control unit (MCU) of the NC machine tool by a behind the tape reader interface. In operation, the general purpose computer is used on a time share basis to generate a suitable machine control program. The machine control program is transferred to the dedicated microprocessor by means of the telecommunication data set. Thereafter, the machine control program may be edited or revised on a real time basis at the machine tool. Once the machine control program is found acceptable, it is independent of the host computer and it may be shifted from one machine to another independently of machine tool location.

Apparatus and method for providing multiple ultrasonic sector image displays

Abstract: The apparatus includes an input controller connected to receive input data representing ultrasonic sector images of a patient for digitizing selected ones of the images thereby representing those images in a digital format. A front panel interface is provided for specifying the selected ones of the sector images to be digitized. Storage means are provided for storing the digitized data and processor means are provided for controlling the digitizing and storing of the input sector data and for enhancing the digital images. Display means are provided for displaying the enhanced sector images.

Malfunction detection system for a microprocessor based programmable controller

Abstract: Fault detection hardware is employed at the I/O interface racks of a programmable controller to detect fault conditions which may occur there. An I/O fault line is connected in daisy chain fashion between the I/O interface racks and the controller processor, and when a fault is indicated at any of the I/O interface racks, it is communicated to the controller processor through this line. The indicated I/O fault freezes, or holds, a microprocessor in the controller processor, and if the I/O fault persists for a preselected time interval, all operating devices connected to the programmable controller interface racks are decontrolled. A watchdog timer is also provided in the controller processor for detecting malfunction conditions which may occur at the processor. When such a condition is detected, the operating devices connected to the programmable controller interface racks are decontrolled.

Microprocessor support system

Abstract: The disclosed microprocessor support system provides a total "laboratory" environment for developing and testing application software as well as for debugging the microprocessor-based application machine itself. The microprocessor support system contains a time shared minicomputer equipped with a full set of peripherals which functions as the main or operating system. A data link connects this operating system with test equipment located at the site of the application machine. This test equipment consists of a field test unit which provides an interface between the application machine, a local keyboard terminal and the operating system such that an engineer at the site of the application machine has access through the field test unit to both the microprocessor-based application machine and the operating system with its sophisticated hardware and software resources to assist in developing and testing application software, as well as debugging the application machine itself.

Maintenance interface for a service processor-central processing unit computer system

Abstract: A maintenance interface is provided for interfacing a service processor and a central processing unit operating asynchronously to each other. The maintenance interface includes circuitry for synchronizing the service processor to the central processing unit and decode circuitry for interpreting commands from the service processor. The maintenance interface also includes circuitry responsive to control signals from the central processing unit such that the maintenance interface establishes communication between the service processor and the central processing unit. The central processing unit includes a microprocessor for interpreting data sent between the service processor and the central processing unit. The maintenance interface is responsive to control signals from the central processing unit to resolve communication contention between the central processing unit and the service processor. The maintenance interface further facilitates the use of the LSSD testing procedure by degating central processing unit interfaces as required for this testing approach.

Computer to recording medium interface

Abstract: A central computer is utilized to control a recording medium while a peripheral computer is utilized to supply data to the recording medium for recording on magnetic tape. Method and apparatus is provided whereby an error indication is provided to the central computer if an error occurs in the transfer of data from the peripheral computer to the recording medium.

Laboratory statistics made simple. Interfacing a clinical chemistry computer system with a general statistical program package.

Abstract: A general-purpose statistical program package (BMDP) has been linked by a simple program interface to the data file of a clinical chemistry laboratory's computer system. This system may be used for various types of statistical data analysis based on the laboratory's routine work.

Micronet: A reconfigurable microcomputer network for distributed systems research:

Abstract: MICRONET is a reconfigurable network of closely cou pled microcomputers intended for general-purpose com puting. The initial system will consist of 16 Digital Equipment Corporation LSI-11 microcomputer nodes, each with its own set of peripherals. The nodes are linked via front-end computers which send packet-switched messages over shared buses which form a passive com munications network.The specially designed front ends are on interface cards which fit in LSI-11 backplanes in each node. Each front end controls three high-speed ports: two for communications on shared buses at 0.7 megabytes per second and one for direct memory access at 0.3 megabytes per second to the LSI-11. Each front end contains 4096 bytes of memory for use in queuing message packets. Each uses two microprocessors: a Signetics 8X3006 for logic control and a Zilog Z-808 for communications routines.MICRONET has been designed to be a flexible research and simulation tool for studying distributed computer hardware and software. The topolog...

The user — cordial interface

Abstract: A great deal of effort has been expended on the topic of user‐oriented interface (UOI) to online retrieval systems. This paper discusses the contradictory nature of the phrase UOI as commonly applied to retrieval systems today and describes a different approach to the problem made feasible through improvements in the technnology.

Commercial applications of ate

Abstract: The need for custom designed Automatic Test Equipment (ATE) for production testing of high volume commercial and consumer electronics is explored. Topics discussed include economic rationale, hardware and software design considerations, hardware interface, operator interface as well as the relationship between the ATE supplier and his customers.

A rule-based approach to knowledge acquisition for man-machine interface programs

Abstract: The development of computer programs, called agents, that act as man-machine interfaces for computer users are described. These programs are written in RITA: the Rule-directed Interactive Transaction Agent system, and are organized as sets of IF-THEN rules or “production systems.” The programs, or “personal computer agents,” are divided into two main categories: those that interface the user to computer systems he wishes to use and those that interact with the user to acquire the knowledge needed to create these interface programs. The relationship between the interface program and the knowledge acquisition program is that of parent-offspring. Three types of parent-offspring RITA agent pairs are described: (1) an exemplary programming agent that watches a user perform an arbitrary series of operations on the computer and then writes a program (a task agent) to perform the same task; (2) a tutoring agent that watches an expert demonstrate the use of an interactive computer language or local operating system and then creates a teaching agent that can, help naive users become familiar with the language or system demonstrated by the expert; and (3) a reactivemessage creating agent which elicits text from a user (the sender) and from it creates a new RITA agent which is a reactive message. The reactive message is sent to some other user (the recipient) who interacts with it. During the course of the interaction a record of the recipient's responses is sent back to the sender.

Data acquisition system for electrochemical applications

Abstract: A low cost data acquisition system for electrochemical cells has been devised on the basis of the new microprocessor computer generation with IEC-BUS interface connections. This modular structure allows the application and extension of the proposed system to all IEC-BUS† compatible measuring apparatus. Our special interest was focused on the control of experiments with a large data flow like impedance spectroscopy as well as long time experiments like the temperature dependence of a cell e.m.f. Beside this, experiments like d.c.-conductivity, discharge characteristics and current-voltage curves can easily be carried out. The programs have been developed in a way which allows an application of the system in scientific laboratories as well as in the routine quality control of electrochemical device production.

Interface apparatus for coupling a minicomputer to a microcomputer for the transfer of data between them and method for using same

Abstract: Interface apparatus which facilitates asynchronous parallel transfer of data at a speed of up to at least 1.6 megabits per second between a minicomputer and a microcomputer. The apparatus includes a plurality of bidirectional data circuits parallel coupled between the minicomputer and the microcomputer for carrying data between the minicomputer and the microcomputer when either computer wants to send data to the other computer. The apparatus also includes data transfer control circuitry coupled between the minicomputer and the microcomputer for permitting either computer, when it wants to send data, to: (a) indicate by means of a first or second control signal to the receiving computer that the sending computer wants to transmit data over the data circuits, (b) resolve contention between the computers for access to the interface apparatus, (c) enable the receiving computer to indicate to the sending computer that the receiving computer is ready to receive data over the data circuits, (d) effect transfer of data from the sending computer to the receiving computer over the data circuits, and, (e) enable the receiving computer to indicate to the sending computer that the receiving computer has received the data.

Interface between data reading wand and cash register display

Abstract: Circuitry receives data information from a wand and decodes the same for duplicating a keyboard input to a display. The interface circuit includes a plurality of switches paralleling the keyboard input switches and generates autonomously a control signal indicative of a status of the display.

Automated clean-out system for film processors

Abstract: Disclosed herein is an automated system adapted to be connected to commercial film processors, the system including a common automated sequencer for advancing the wash, rinsing and fill cycles in both the developer and fixer containers To accommodate the level requirements in the various containers and the variations in pumping rate there are periodic wait logic sections which bring the developer and fixer cycle into synchronism The foregoing system includes an interface panel provided with level detectors and the necessary interconnections with the commercial units

IEEE standard 488 and microprocessor synergism

Abstract: The assembly and use of more new and versatile instrumentation systems is now enhanced dramatically with the widespread application of IEEE Standard 488-1975, "Digital Interface for Programmable Instrumentation." This Standard interface provides an easy-touse high performance concept that links instruments, calculators or computers, and peripheral devices to function as automated instrumentation systems. Microprocessor technology applied to both smart instrumentation and the implementation of IEEE Standard 488's interface functions provides still further benefits to system designers and users. This article describes both the interface function concepts important to instrumentation systems and the roles played by IEEE Standard 488 and microprocessor techniques in support of these functional concepts. Microprocessor and IEEE Standard 488 interface techniques combine to provide designers and users with significant new tools for improved product performance, something neither technology alone could provide. In the near future, special LSI chips optimized to integrate the two technologies should further enhance the benefits for all concerned.

Interface conversion device

Abstract: PURPOSE:To regard the analog facsimile unit as identical to the data communication terminal unit for a data communication system and to secure an easy connection to the electronic computer facilities.

A multi-user on-line 8080 microcomputer system

Abstract: A laboratory control system based upon the Imsai 8080 microcomputer is described. This system is capable of programming separate events in each of five animal operant chambers and recording the resulting behavioral data. The interface between the computer and the chambers is compatible with the 28-V dc nature of these chambers and various peripheral devices, such as cumulative recorders. At present, system software is based on the 8080 assembly language, while the BASIC language is used for data analysis. Cost considerations and comparisons with minicomputers are discussed.

A microcomputer-based control and communication system for the severely disabled

Abstract: A microcomputer-based environmental control and communication system for the severely disabled has been developed. By puffing and sipping on a tube the user can store messages in computer memory and control a number of peripheral devices. A scanning method of operation is employed in which characters are selected for message building or control purposes from lists displayed on a CRT. An interface system is presently being developed to allow the computer to control peripheral devices by transmitting coded signals over the power mains.