Louise H. Jones

An information processing framework for understanding success and failure of MIS development methodologies

Abstract Organizations seeking to improve systems development performance have implemented a variety of project methodologies. The success of these efforts has been mixed. Some organizations have found that implementation of a systems development methodology leads to on-time, within budget project completions with improved productivity; others have experienced reduced productivity. This paradox can be explained by viewing both systems development and the methodology development in terms of two key information processes - uncertainty reduction and equivocality resolution. Project methodologies that are implemented with the procedures, definitions, and policies necessary to reduce the uncertainty and resolve the equivocality associated with the systems development process can be successful only if the management of the process allows those mechanisms to be fully utilized. Implementation experiences with a particular methodology in different environments discussed here demonstrates that equivocality resolution during the implementation process is critical to realizing improved productivity. Suggestions for management action necessary to resolve equivocality during the implementation of a systems development methodology are discussed.

Trends in Microprogramming: A Second Reading

Microprogramming is a rapidly emerging technology for the implementation of the control section of modem digital processing systems. An assessment was made of this approach to control unit design three years ago in a series of papers derived from the Third Annual Workshop on Microprogramming and published as a special issue of this TRANSACTIONS. This technology has matured in the ensuing three years, and an updated assessment has been prepared again as a special issue of this TRANSACTIONS based upon the papers presented at the Sixth Annual Workshop. The extent of realization of past predictions is reviewed and current trends are discussed. Finally, an attempt is made to assess future developments that may be expected to occur in the applications of microprogramming.

Corporate productivity and shared information technology

Abstract Corporations have made large investments in information technology over the past thirty years. The current trend is to continue this investment in shared information technology (SIT), including such tools as electronic mail, distributed databases, teleconferencing, and group decision support systems. However, investment in SIT may not be appropriate for or beneficial to every company. This paper suggests that in order for SIT to be successfully implemented within a firm the corporate culture must be one that supports the sharing of information across traditional organizational boundaries. Further, the particular SIT tool selected must allow the same type of communication to take place as does the traditional communications mechanism that it is intended to replace. General guidelines are given for firms concerning conditions under which high return SIT can be implemented.

The role of instruction sequencing in structured microprogramming

The current literature is filled with descriptions of various microprogrammed processors and discussions of the improvements in performance that can be realized through microprogramming. Thus, Tucker and Flynn [1] describe a dynamically microprogrammed processor and give several examples of problem-oriented programming in which the performance of the microcode was much better than that of assembly language code (System/360, normalized technology). Recently, Abd-alla and Karlgaard [2] have developed an algorithm for the synthesis of applications-oriented microcode for a dynamically microprogrammed computer. Their paper gives examples of problem-oriented architectures (realized through specialized instruction sets) which have much better performance than the corresponding general purpose architectures. This trend toward realizing specialized computer systems by means of writable control store probably means that more people will be writing microcode in the future. In particular, it seems worthwhile to consider the relation of the instruction sequencing functions of a given machine to both the ease of writing correct microcode and the size of control memory required for that machine. So far there seems to have been little or no discussion of this topic in the literature [3].

Functional memory-based dynamic microprocessors for higher level languages

Dynamic microprocessors have been proposed as a means for providing the basic instruction sets necessary for efficient processing of a variety of higher level languages with specific hardware. Functional memory-based dynamic processors consisting of a collection of identical modules formed from writable associative arrays offer a more general solution to this problem. The basic properties of functional memory modules are discussed; and the structure of a functional memory-based microprocessor suitable for executing the SNOBOL 4 replacement statement using the data structures defined by Griswold (15) is given.

Controlled graphs and instructions

This paper is concerned with controlled graphs, a graph-theoretic formalism which was developed from the study of microprogramming. In this formalism, a microinstruction is equivalent to a subgraph of the graph representing the (microprogrammed) computer, and the problem of designing a micro-instruction is simply that of finding an appropriate subgraph. However, this idea can be generalized and applied to other networks which are characterized by flows of discrete elements. The results of one instruction or of a sequence of instructions, a natural notion for a programmer, are developed for controlled graphs in this paper.

Teaching microprogramming(Panel Discussion)

The following are excerpts from the material that will be discussed by the panelists: “Microprogramming and Emulation”. This experimental seminar was directed toward learning about microprogramming rather than how to microprogram because of lack of equipment. Some of the topics discussed were: Organization of Microprogrammable Machines, Languages f o r Microprogramming, Synthesis of System Architectures, Emulation and Signal Processing, and the Future of Microprogramming. Student projects from the course included an ALGOL simulation of the HP 2100 and the John Hopkins dynamic multiprocessor and a simulation package to investigate the emulation of the AN/UYK-20.—L.H. Jones “CIS 672 - Microprogramming”. The objectives of this course are (1) teaching the basic principles of microprogramming, (2) to develop the students ability to write microprograms and evaluate machines, (3) to demonstrate the potential of writable control store and, (4) to prepare students to do research in the microprogramming field . Material covered in the course includes: A review of control structures and history of microprogramming, development of microprograms for functions and emulators and future trends and research topics in microprogramming.—E.W. Reigel “Microprogramming Theory” This is a graduate level course that takes up where our introductory course in microprogramming leaves off. The prerequisites are a basic understanding of microprogramming and the ability to write and debug microprograms. The course begins with discussion of control structures and micro-memory. Particular attention is placed upon microword encoding, time validity, and sequencing techniques. Micro-programming languages are developed from the standpoint of those which assume a particular hardware configuration (e.g. IBMs CAS) to those which include virtual machine definition capability (e.g. Youngs ALSIM).—W.G. Sitton “Microprogramming Activities at Northwestern University”. The equipment at Northwestern has been used to develop a senior/graduate course and to provide facilities for Master and Ph.D. research. The Varian V73 has been used in a variety of projects including the development of a microprogram monitoring device study microprogram resource utilization, the implementation of microprogram parallelism detection techniques and the development of a high level language for V73 microprogramming.—M. Tsuchiya