Interfaces in Computing最新文献

High energy physics experiments are studying more and more exotic processes at ever-increasing energies. Enormous quantities of data must be measured and processed. This challenge can only be met by the use of computers throughout the experiments. An overview is given of how different applications each require specific hardware and software.

This paper describes the design and implementation of a kernel suitable for interfacing software written in a high-level distributed or concurrent programming language to the underlying multi-microcomputer environment. The kernel enables processes residing on different processors to execute in parallel, while processes allocated to the same processor are executed in a multiprogramming environment. Functions provided by the kernel include process management, memory management, input/output control and interrupts service. Processes can communicate with each other and synchronize themselves by means of the monitor construct or message passing.

This paper investigates the question of optimal lengths for command lines in dialogue management systems. The results of an experiment investigating typographical errors as a function of line length are presented. A feasibility study is made of the use of a similarity function for the dynamic processing of abbreviations. Recommendations are made for the design of a dialogue management system.

In this paper the development of a local area network based on Ethernet running a remote procedure call protocol is described. A working definition of the software protocol is provided together with the implementation details for an LSI 11/23 computer running RT11 and for a VAX 11/750 computer running VMS. The performance characteristics of this network have been measured and data rates of at least 62 kbytes s⁻¹ have been consistently recorded for disk-to-disk data transfer between these two machine types.

A digital-circuit-switched telecommunications network and its associated supervisory system in use at Sandia National Laboratories, Albuquerque, NM, are described in this paper. The network currently services over 1600 terminals and workstations as well as 600 computer ports. The seven circuit switches which constitute the switching network are distributed in a campus-like environment. While the circuit switches are commercial microprocessor-controlled port contenders, the controlling software has been extensively modified to meet the specific needs of this Department of Energy laboratory. The supervisory system, consisting of interconnected processors located in the major communications centers, forms the interface between operations personnel and the network switches. The processors provide a display of network activity and a convenient method of submitting commands to the individual switches. In addition, the supervisory system gathers network usage statistics, logs all system activity and generates periodic reports detailing usage.

A new high speed serial CAMAC system developed at Stanford Linear Accelerator Center for general use in control systems and experimental applications is described in this paper. The line protocol on which the system is based will be described, followed by the serial branch driver and CAMAC crate controller which support this protocol. The serial branch driver contains an assortment of scan modes particularly useful for data gathering in experiments.

A communication link which has been developed between a microcomputer and a mainframe to support several requirements encountered in the context of research projects dealing with handwritten signature verification and character recognition is described in this paper. The software package, which has been coded in assembly language, allows on-line transmission of data from the microcomputer memory, the keyboard or diskette files to the host. It permits reception of data on the screen, the printer or the files of the microcomputer. Two approaches to error detection an and recovery have been sequentially implemented. A summary of the transmission algorithm is presented with the help of a schematic pseudocode.

A one-day short course entitled “Personal Computers in Nuclear Instrumentation” was given in conjunction with the IEEE's 1984 Nuclear Science Symposium. The course was intended to be introductory in nature, but for an audience of scientists and engineers. The course began with a discussion of the hardware normally associated with personal computers, followed by this introduction to the software.

A technique for implementing authentication schemes in distributed systems, based on capability list protection mechanisms, is described in this paper.

Capabilities are generally supported by the hardware in the network nodes where client authentication is required by a server in order to perform the invoked service correctly. High efficiency can then be achieved by suitably mapping the access list check, required when services are requested by remote users, into a capability list check.

This is performed by means of “interlocutor” processes belonging to the node where the service provider resides. In this paper an implementation of the proposed scheme based on the Intel iAPX-432 microprocessor is introduced. The hardware support in the iAPX-432 can be used to enforce object protection as well as to minimize the overhead introduced in checking the client's identity.