The C programming language: Popularity grows for the high-level assembly language

The programming language C is becoming increasingly popular. It has many advantages over PASCAL and BASIC for use with PCs. It is known as a high-level assembly language, and provides useful tools for programmers.     

An algol-like assembly language for a small computer

In a classic paper¹ Wirth describes a language which combines the readability of ALGOL 60 with the flexibility and degree of control of a conventional assembly language. This paper gives an outline of a similar language for a small 16-bit computer—the Honeywell DDP-516. Implementing the compiler in its own language by recoding an ALGOL version of the compiler has shown that the language is suitable for large systems. With the compiler written in a high-level language, many enhancements have been possible even though these were not envisaged in the original coding This use of the language clearly demonstrated that a high-level assembly language can be a very effective tool for a small machine as well as for computers like the 360 series.     

The design and implementation of a high-level language converter

There is now a good understanding of problems encountered in the design, implementation and use of a high-level language converter. These general issues are illustrated in terms of an account of the design and implementation of one particular converter, which converts programs from Pascal-SC (a Pascal dialect) to Ada. A specific aim of the presentation is to provide guidance for those contemplating future language conversion projects.     

Implementing LISP in a high-level language

The problems of producing an efficient but robust implementation of a high-level language by building on existing compilers are discussed with reference to a LISP system consisting of an interpreter, a compiler and a large collection of support routines. In retrospect it can be seen that almost all of the major difficulties encountered were facets of a general problem concerned with the global control of the use of store. The garbage collector, originally intended solely to manage the LISP heap, extends its scope to simplify the solution of many of these problems.     

Jade: a high-level, machine-independent language for parallelprogramming

Jade, a high-level parallel programming language for managing coarse-grained parallelism, is discussed. Jade simplifies programming by providing sequential-execution and shared-address-space abstractions. It is also platform-independent; the same Jade program runs on uniprocessors, multiprocessors, and heterogeneous networks of machines. An example that illustrates how Jade programmers express irregular, dynamically determined concurrency and how the implementation exploits this source of concurrency is presented. A digital video imaging program that runs on a high-resolution video system and several other examples of Jade applications are described     

A computer simulator for use in an introductory course on computer systems and assembly language programming

This paper describes a simulator for a computer system comprising a simple central processor, memory and a variety of peripheral devices. The simulator is used in the laboratory component of an introductory course on computer systems and assembly language programming. The simulator exploits the limited “cursor graphics” capabilities of commonly available display terminals; the graphics are used to present a view of the internal operations of the simulated computer.     

The development of a specification language for a computer security system

The primary goal of this paper is to define an initial step towards the definition of ‘systems grammar’ based on the notion of formal languages which can be used as a ‘tool’ in the formal representation of computer security systems. Currently all modelling done on computer security systems is written up as mathematical models. These mathematical models are usually based on the mathematics of relations amongst objects, as opposed to the model described in this paper which is based on the theory of formal languages. This paper is aimed at people who are doing research on the logical aspects of computer security. It is the first of a series of two papers. This paper will give interim results and make more specific the definition of a ‘formal language’ which suits the computer security environment. The second paper will illustrate the actual use of the defined ‘formal language’ and show how to represent the characteristics of a computer security environment by using this ‘formal language’.     

Adding graphics to a high-level programming language

When graphics input/output capabilities are added to a programming language originally designed with a text stream input/output model, various design decisions affect the ease with which the graphics facilities are learned and used by applications programmers. In adding window system facilities to the Icon programming language, some design decisions were made very differently from the conventional wisdom, resulting in substantial benefits for programmers. In addition, some pre-existing Icon language features have proved to be useful in graphics programming.     

Identification in a high-level graphics programming language

This paper describes programming elements for the identification in the high-level graphics programming language PASCAL/Graph [1]. The result is an extended form of the so-called indirect identification model. The identification process takes place in three steps: the user interaction, the search through the relevant graphical data, and the logical inquiry. By this method all reasonable identification actions can be formulated in a device-independent manner and also implemented efficiently. The concept can be carried over to other graphics programming languages easily.     

FORK: A high-level language for PRAMs

We present a new programming language designed to allow the convenient expression of algorithms for a parallel random access machine (PRAM). The language attempts to satisfy two potentially conflicting goals: On the one hand, it should be simple and clear enough to serve as a vehicle for human-to-human communication of algorithmic ideas. On the other hand, it should be automatically translatable to efficient machine (i.e. PRAM) code, and it should allow precise statements to be made about the amount of resources (primarily time) consumed by a given program. In the sequential setting, both objectives are reasonably well met by the Algol-like languages, e.g. with the RAM as the underlying machine model, but we are not aware of any language that allows a satisfactory expression of typical PRAM algorithms. Our contribution should be seen as a modest attempt to fill this gap.     

Molecule: a language construct for layered development of parallelprograms

A new language construct, called molecule, is described for the efficient implementation of algorithms on parallel computers. A molecule can be considered a procedure associated with a molecule type. Each molecule type characterizes a particular computation mode (sequential, pipelining, array processing, dataflow, multiprocessing, etc.). Basic concepts of molecule are introduced with a procedural language, called PAL. A concrete example is presented to illustrate layered software development using PAL on a multicomputer (the iPSC). It is concluded that high-level languages, augmented with the molecule construct, offer application flexibility, user friendliness, and efficiency in implementing parallel programs     

The high-level graphics programming language PASCAL/Graph

A high-level programming language like PASCAL offers data types, variables, constants and operators, with which the programmer can represent the actual world as a model inside the computer. The world of numbers and text has been represented in the computer for many years by various kinds of variables. The importance of computer graphics is increasing extremely fast. But the development of high-level programming languages, which include standard constructs for processing graphical informations, is far from where it could be. A good system should be based on understandable concepts, easy to learn and similar to normal programming, so that the programmer can fully concentrate upon the design of his pictures[1–4]. For these purposes PASCAL/Graph³ was designed and implemented[5–8].     

Programming the 68000 in high-level language for VME

Many choices of VME hardware module now exist but software still continues to be the major cost in systems development. As development teams face more complex projects, productivity can be improved by four approaches: the use of standard system architecture, the use of software building blocks, the use of better tools and an increase in the level of software engineering management. Some characteristics of realtime systems programming are presented. Next an overview of the VMEbus is given. Then a target operating environment for 68000-based applications in PASCAL is described. The software components are called pSOS, pHILE and pROP. These provide the realtime executive or kernel, file management system and runtime support for PASCAL respectively. Languages other than PASCAL can be used with pSOS and pHILE, but a preference is expressed for PASCAL over the language C.     

The changing construct of computer anxiety for younger and older adults

A revalidation of a previously developed computer anxiety scale (Marcoulides, 1989) indicated changes in the factor structure for both younger and older adults. Two factors emerged — Direct and Indirect Involvement with computers — as compared with the previous two factors of General Computer Anxiety and Equipment Anxiety. This suggests that the construct of computer anxiety may have changed, perhaps because of the rapid changes in computers and the technological environment. Additional results showed that, while the factor structure was similar for younger and older adults, two items differentially loaded on the two factors. These results suggest the need for further examination of computer anxiety with older adults, with the possibility of developing computer anxiety scales specifically for older adults.