A software lineage

The author traces the lineage of the DEC software to the present day. The hardware legacy of the Digital Equipment Corporation (DEC) is well documented. From its humble beginnings in an abandoned New England textile mill as a specialized peripheral manufacturer, DEC grew to become one of the dominant computer companies in the 1970s and 80s. DEC engineers produced landmark computers, such as the PDP-8, PDP-11, and VAX. At the company's height, DEC hardware was synonymous with university, engineering, and research computing, but its machines could also be found in hospitals, financial institutions, and offices. The article outlines the operating systems developed by DEC for its machines     

RJ: a Java package providing JR‐like concurrent programming

The JR concurrent programming language extends Java with a richer concurrency model, by adding several new types and statements. JR provides dynamic remote virtual machine creation, dynamic remote object creation, remote method invocation, dynamic process creation, rendezvous, asynchronous message passing, semaphores, concurrent invocation, and shared variables. This paper presents RJ, a package for Java that provides JR‐like features. The paper gives an overview of RJ and its key features; describes the implications of RJ's design, including how RJ provides additional, useful flexibility; discusses the implementation of RJ; and gives qualitative and quantitative evaluations of our work with respect to feasibility and usability, experimentation, migration, and performance. RJ has been successful in meeting these goals and in providing insight into the trade‐offs between using a concurrent programming language versus using the equivalent concurrent package. Our work has yielded a few surprises in dealing with some concurrent programming language features, in understanding the run‐time performances of JR versus RJ programs, and in obtaining some additional, useful flexibility for concurrent programming applications. Copyright © 2015 John Wiley & Sons, Ltd.     

Implementation of the EARTH programming model on SMP clusters: a multi‐threaded language and runtime system

This paper describes the design and implementation of an Efficient Architecture for Running THreads (EARTH) runtime system for a multi‐processor/multi‐node cluster. The (EARTH) model was designed to support the efficient execution of parallel (multi‐threaded) programs with irregular fine‐grain parallelism using off‐the‐shelf computers. Implementing an EARTH runtime system requires an explicitly threaded runtime system. For portability, we built this runtime system on top of Pthreads under Linux and used sockets for inter‐node communication. Moreover, in order to make the best use of the resources available on a cluster of symmetric multi‐processors (SMP), this implementation enables the overlapping of communication and computation. We used Threaded‐C, a language designed to implement the programming model supported by the EARTH architecture. This language allows the expression of various levels of parallelism and provides the primitives needed to manage the required communication and synchronization. The Threaded‐C programming language supports irregular fine‐grain parallelism through a two‐level hierarchy of threads and fibers. It also provides various synchronization and communication constructs that reflect the nature of EARTH's fibers—non‐preemptive execution with data‐driven scheduling—as well as the extensive use of split‐phase transactions on EARTH to execute long‐latency operations. Copyright © 2003 John Wiley & Sons, Ltd.     

Fei Teng 64 Stream Processing System: Architecture, Compiler, and Programming

The stream architecture is a novel microprocessor architecture with wide application potential. It is critical to study how to use the stream architecture to accelerate scientific computing programs. However, existing stream processors and stream programming languages are not designed for scientific computing. To address this issue, we design and implement a 64-bit stream processor, Fei Teng 64 (FT64), which has a peak performance of 16 Gflops. FT64 supports two kinds of communications, message passing and stream communications, based on which, an interconnection architecture is designed for a FT64-based high-performance computer. This high-performance computer contains multiple modules, with each module containing eight FT64s. We also design a novel stream programming language, Stream Fortran 95 (SF95), together with the compiler SF95Compiler, so as to facilitate the development of scientific applications. We test nine typical scientific application kernels on our FT64 platform to evaluate this design. The results demonstrate the effectiveness and efficiency of FT64 and its compiler for scientific computing.     

Mirror‐based reflection in AmbientTalk

This paper introduces a novel mechanism to perform intercession (a form of reflection) in an object‐oriented programming language with the goal of making the language extensible from within itself. The proposed mechanism builds upon a mirror‐based architecture, leading to a reusable reflective application programming interface that cleanly separates interface from implementation details. However, support for intercession has been limited in contemporary mirror‐based architectures. This is due to the fact that mirror‐based architectures only support reflection explicitly triggered by metaprograms, while intercession requires reflection implicitly triggered by the language interpreter. This work reconciles mirrors with intercession in the context of an actor‐based, object‐oriented programming language named AmbientTalk. We describe this language's full reflective architecture, highlighting its novel mirror‐based approach to reflect upon both objects and concurrently executing actors. Subsequently, we apply AmbientTalk's mirror‐based reflection to implement two language features, which crucially depend on intercession, to wit future‐type message passing and leased object references. Copyright © 2008 John Wiley & Sons, Ltd.     

MICROTEXT: a new dialogue programming language for microcomputers

MICROTEXT is a new dialogue programming language that has recently been developed by the United Kingdom's National Physical Laboratory. This paper presents an overview of the language, describes its mechanism of program creation and then provides some examples of its use in the context of dialogue engineering.     

Structural analysis software and the C programming language

The C programming language is becoming popular in the application software development. The advantages of C are due to its compactness, modularity, faster execution speed and portability. This paper reviews the various features of C and its suitability in structural analysis software development. A quantitative comparison is made between C and Fortran by developing a truss analysis program in both languages. These programs are tested for execution speed on a VAX 11/785, SUN workstation and an IBM-PC/AT. The results of this investigation show that future software development in structural engineering should consider C as a viable alternative to the traditional programming languages.     

触发器在数据库编程中的应用

针对当前数据库编程中数据不匹配的现象,采用触发器可以有效地解决这方面的问题。首先介绍了触发器的概念、优点及作用;其次从触发器的原理、使用注意事项、创建、查看、修改、修改触发器及触发器嵌套等几个方面来介绍触发器的使用;最后将SQL与C#语言相结合,给出了查询触发器与修改触发器的核心代码。对于数据库管理人员和软件开发人员有着一定的积极作用。     

An assembler and disassembler framework for Java™ programmers

The Java™ programming language is primarily used for platform-independent programming. Yet it also offers many productivity, maintainability and performance benefits for platform-specific functions, such as the generation of machine code.

We have created reliable assemblers for SPARC™ , AMD64, IA32 and PowerPC which support all user mode and privileged instructions and with 64 bit mode support for all but the latter. These assemblers are generated as Java source code by our extensible assembler framework, which itself is written in the Java language. The assembler generator also produces javadoc comments that precisely specify the legal values for each operand.

Our design is based on the Klein Assembler System written in Self. Assemblers are generated from a specification, as are table-driven disassemblers and unit tests. The specifications that drive the generators are expressed as Java language objects. Thus no extra parsers are needed and developers do not need to learn any new syntax to extend the framework for additional ISAs.

Every generated assembler is tested against a preexisting assembler by comparing the output of both. Each instruction’s test cases are derived from the cross product of its potential operand values. The majority of tests are positive (i.e., result in a legal instruction encoding). The framework also generates negative tests, which are expected to cause an error detection by an assembler. As with the Klein Assembler System, we have found bugs in the external assemblers as well as in ISA reference manuals.

Our framework generates tens of millions of tests. For symbolic operands, our tests include all applicable predefined constants. For integral operands, the important boundary values, such as the respective minimum, maximum, 0, 1 and −1, are tested. Full testing can take hours to run but gives us a high degree of confidence regarding correctness.     

Finite element analysis on the BBN butterfly multiprocessor

Applications of the finite element method can easily exhaust CPU and memory resources on conventional uniprocessor machines, and are thus prime candidates for multiprocessor application. In order to investigate various parallel processing methodologies and to evaluate their performance, we have developed a finite element program for the Butterfly Parallel Processor. The overall organization of the program and its data structures are described along with parallel implementations of well-known algorithms for transient and static analysis. Results are presented for two implementations of explicit time integration, and for static analysis using a parallel version of Gaussian elimination. For comparison, results from running the same program on a DEC VAX 11/785 are also included. The transient cases yielded near-linear (within 2.5%) speedup in the full range of 1–64 processors; the static case results showed significant nonlinearity over the same range.     

面向国产异构众核系统的Parallel C语言设计与实现

异构众核架构具有超高的性能功耗比,已成为超级计算机体系结构的重要发展方向.但众核系统更为复杂的并行层次和存储层次,给编程和优化带来了极大的挑战,因此研究面向众核系统的并行编程技术,对于降低国产众核系统并行应用的编程难度、提升并行程序的性能都具有重要的意义.提出统一架构的多模式并行编程模型,包括异构融合的加速运算模型和按同构方式编程的自主运算模型,根据编程模型设计了Parallel C语言,能有效描述国产众核系统的异构并行性,与其它众核系统上MPI+X的使用模式相比,编程和系统优化都具有全局视角,在多级局部性描述、单边消息、兼容已有多核应用等方面具有特色;基于Open64构建了Parallel C编译系统,全面支持加速运算模型和自主运算模型,提出并实现了数据布局与自动DMA、编译指导的线程代理和拓扑位置感知的集合通信等优化.Micro Benchmark和实际应用在神威太湖之光计算机系统上的测试数据表明,Parallel C语言和编译系统具有良好的性能和可扩展性,能够有效支撑大型应用.     

DFL: A Data Flow Language

Many novel computer architectures like array and multiprocessors which achieve high performance through the use of concurrency exploit variations of the von Neumann model of computation. The effective utilization of the machines makes special demands on programmers and their programming languages, such as the structuring of data into vectors or the partitioning of programs into concurrent processes. In comparison, the data flow model of computation demands only that the principle of structured programming be followed. A data flow program, often represented as a data flow graph, is a program that expresses a computation by indicating the data dependencies among operators. A data flow computer is a machine designed to take advantage of concurrency in data flow graphs by executing data independent operations in parallel. In this paper, we discuss the design of a high level language (DFL: Data Flow Language) suitable for data flow computers. Some sample procedures in DFL are presented. The implementation aspects have not been discussed in detail since there are no new problems encountered. The language DFL embodies the concepts of functional programming, but in appearance closely resembles Pascal. The language is a better vehicle than the data flow graph for expressing a parallel algorithm. The compiler has been implemented on a DEC 1090 system in Pascal.     

试谈C语言程序设计教学

C语言凭借其丰富的数据结构、优良的机构性灵活性为电脑编程工作的人推崇学习。C语言作为一门基础课程,在高等院校计算机专业和很多的非计算机专业中开设,具有十分重要的作用和意义,它不仅能锻炼学生的思维逻辑能力,还为很多课程,如数据结构、单片机和其他程序设计语言打下良好的基础,具有引导性的作用。根据教学过程中学生常出现的问题,总结出了在C语言教学过程中的几点教学方法。     

Two approaches to on-line graphics systems

This article describes two types of software systems which provide an interface to users who wish to apply the power of interactive graphics to their specific problem. The systems are based on an 8K IMLAC PDS-1 minicomputer CRT display which provides sufficient processor power to handle display generation, management, and dynamic manipulation. The minicomputer software was first designed as an independent operating system which not only provides the user with high-speed timesharing access to the host computer, but also the resources of the local processor and its associated input/output devices. In this configuration, host compiled FORTRAN IV programs are loaded into the minicomputer through the timesharing link and executed independently from the host processor. A higher degree of processing is provided by the master-slave relationship between a local DEC PDP $\text{11}\text{40}$ minicomputer and the IMLAC. The user's FORTRAN IV program, executing in the PDP $\text{11}\text{40}$, directs an IMLAC graphics subsystem through subroutine calls. These systems provide the programmer with a foundation for a broad range of high level applications involving computer graphics.     

Towards a Programming Language for Interaction Nets

Interaction nets were introduced almost 15 years ago. Since then they have been put forward as both a graphical programming paradigm and as an intermediate language into which we can compile other languages. Whichever way we use interaction nets, a problem remains in that the language is very primitive. Drawing an analogy with functional programming, we have the λ-calculus but we are missing the functional programming language: syntactic sugar, language constructs, data-structures, etc. The purpose of this paper is to make a first step towards defining such a programming language for interaction nets.     

Uniforms: an automatic forms facility

An automatic forms facility has been built which provides an editor for designing forms and a reporting facility to display information about a form. Furthermore it provides a set of functions which, when linked to an application program, display the forms and accept data supplied by the user at run time. The forms facility was developed in the C programming language and is implemented on a DEC Vax-11/750 running VMS.     

The trio operating system

This paper is an overview of the Trio system which enables users to simultaneously develop and execute programs at three terminals. The system consists of an operating system written in Concurrent Pascal and a set of standard programs written in Sequential Pascal. The system has been used on a PDP 11/55 minicomputer since spring 1979. This work concludes 5 years of experience with the first abstract language for concurrent programming.     

Early experience with the Visual Programmer's WorkBench

The Visual Programmer's WorkBench (VPW) addresses the rapid synthesis and customization of environments for the specification, analysis, and execution of visual programs. The goal of VPW is to enable the easy creation of environments for visual languages. The design of VPW and experience using it to generate a distributed programming environment for a concurrent visual language are described. A visual programming environment for the PetriFSA language generated with VPW is outlined. An overview is provided of the language definition model and its relation to the logical architecture of VPW. Details are given of the language specifications used in VPW, and its application in defining the PetriFSA language. A language-based environment for a specific visual language is generated in VPW from a specification of the syntactic structure, the abstract structure, the static semantics, and the dynamic semantics of the language. VPW is built around a model of distributed processing based on a shared distributed memory. This framework is used in defining the architecture of the environment and for the execution model of visual languages