Narasimhaiah Gorla

Effect of software structure attributes on software development productivity

Improving programming productivity and controlling software costs are very important tasks for an information system manager. Program structure is defined to be the organization of program elements within a program. In this research, we examine the relationship between programming productivity and program structure measures in a COBOL programming environment. Structure measures considered are span of control, levels of control, and their derivatives. The productivity measures considered are program development time and number of computer runs needed. Our results indicate that program development time is significantly associated with span of control and levels of control used in the program. Furthermore, programs having smaller span of control at the top (initial paragraphs) relative to that at the bottom (concluding paragraphs) are associated with the least development times. For illustration purposes, we showed two different program structures, one with low program development time and the other with high development time.

Evaluation of process tools in systems analysis

Abstract Process tools are used during Systems Analysis to describe the process logic of bubbles in Data Flow Diagrams. We conducted two experiments to determine the relative merits of three process tools: Structured English from textual tool category; Decision Tables from tabular tool category; and Nassi-Schneiderman Charts from graphical tool category. We measured three performance types: tool-based comprehension to find understandability of the information in the tool itself; context-based comprehension to find understandability of information in the tool in combination with the information in the rest of structured specification; and the time of comprehension. Unlike most previous research that show graphical tools are the best, our results are different. We show that textual tools (Structured English) are better than both graphical tools (N-S Chart) and tabular tools (Decision Tables), when the problem size is smaller and the users are technically (computer) oriented. The tabular tools (Decision Tables) are better than graphical tools and textual tools, when the problem is moderately large and the users are non-technically (management) oriented.

Debugging effort estimation using software metrics

Measurements of 23 style characteristics, and the program metrics LOC, V(g), VARS, and PARS were collected from student Cobol programs by a program analyzer. These measurements, together with debugging time (syntax and logic) data, were analyzed using several statistical procedures of SAS (statistical analysis system), including linear, quadratic, and multiple regressions. Some of the characteristics shown to correlate significantly with debug time are GOTO usage, structuring of the IF-ELSE construct, level 88 item usage, paragraph invocation pattern, and data name length. Among the observed characteristic measures which are associated with lowest debug times are: 17% blank lines in the data division, 12% blank lines in the procedure division, and 13-character-long data items. A debugging effort estimator, DEST, was developed to estimate debug times. >

Techniques for application software maintenance

Abstract Software maintenance accounts for up to 90% of software lifecycle effort. Software maintenance activities are re-classified into five categories. Reasons for high maintenance costs are described for each maintenance type. Several techniques to reduce current and future maintenance are described and compared. Current maintenance techniques for program browsing, software documentation, and program analysis as well as commercially available computer-aided software maintenance tools are described. Techniques to improve software maintainability, such as software re-structuring, re-engineering, reverse engineering, and defensive programming approach, and techniques to increase the maintenance productivity of future programs are described. Selection criteria in choosing these maintenance techniques and some recommendations for maintenance organization are discussed.

An empirical study of the use of the GOTO statement

Abstract This paper reports on the results of an empirical study on the use of the GOTO statement. A lack of empirical studies on this issue has been acknowledged [1–4]. In this experiment, a total of 311 Cobol programs were input to a Cobol program analyzer for analysis of GOTO usage. The data supplied by the analyzer was then used by SAS (Statistical Analysis System) for statistical analysis. The results of the analysis show that programs with incorrect output used more GOTOs than did programs with correct output. Also, the mean time to debug programs using GOTOs was considerably longer than the mean time to debug GOTO-less programs. There are significant (at the 0.01 level) positive linear and quadratic correlations between the number of GOTOs and debugging time. Furthermore, it is found that programs containing at least one GOTO statement had significantly more “bad performs” (a perform statement invoking paragraphs above, rather than below) than did the GOTO-less programs. Also, in terms of program style, on the average, programs containing at least one GOTO statement had a significantly higher number of mismatched IF-ELSEs, and a higher number of bad indents in True-False tasks, than did programs containing no GOTO statements.

Exploring factors underlying effective office information systems

Abstract Office Automation (OA) traditionally emphasized productivity of the clerical workforce, ignoring higher-level office tasks. Office Information Systems (OIS) are meant to support office tasks done by managers and professionals within a company. By surveying local firms through telephone interviews, we investigate the factors responsible for effective OIS. We analyzed the results by partitioning responses by type of firm, firm size, degree of integration of OIS tools, top management support, and usage of OIS tools. Some findings are: professional service firms reported a greater improvement of productivity due to the introduction of OIS than non-professional service firms. A higher degree of system integration led to higher success rates of OIS in the perspective organization.

Identifying MIS research issues using a research framework

Abstract A research framework is important in identifying the research areas of a discipline. A comprehensive framework is proposed to identify the MIS research issues: a 5 x 5 matrix; it has MIS core activities as one dimension and MIS allied fields as the other. The previously proposed frameworks are mapped into this. Some example research hypotheses are made using the framework, and it is used to determine the areas with inadequate research. The statistics for each of the 25 cells for the period 1979–1987 are obtained using Dialog, a computer-aided aided database. A regression analysis is used to find the growth of each cell of the matrix: most is done in the technological issues of system design and construction. The areas with the least research effort are economic aspects of MIS use/effect, economical aspects of information system operation, and quantitative analysis in MIS management.

Database operating efficiency in fragmented databases in mainframe, mini, and micro system environments

Abstract Vertical fragmentation in database design is the process of assigning attributes to physical segments to improve the database performance. Experiments were conducted to measure the performances of four Fragmentation design methods in the three hardware environments with six transaction mixes, using simulation and quantitative modelling. Some hypotheses are laid down regarding database performance and are validated. The MRGB design method which considered the hardware characteristics produced highest fragmentation in micro (IBM AT), and lowest in mini (Prime), with mainframe (IBM) in between. MRGB design performed the best in the three systems. The Hammer & Niamirs design did its best in mini (61%), and better in mainframe (50%) than in mini (41%) in low update environment. While the fully fragmented design performed the best in micro and the worst in mainframe, the unfragmented design performed the best in mini and the worst in micro.

Is the lack of keyword synergism inhibiting maturation in the MIS theory? an exploratory perspective

Abstract This article explores previous research on keyword search techniques and evaluates the comprehensiveness of a well-known keyword classification scheme. Comparison of literature reviews provide evidence that this topic is not well agreed upon and these contradictions have reduced reliance on keyword searches as a method of exploring prior research on a given topic. Presently, there does not exist a comprehensive management information systems (MIS) keyword list. Information regarding keyword usage in 14676 articles published in 27 MIS journals from 1985–1994 was collected electronically from an ABI Inform database. After several levels of refinements on 4386 keywords, a comprehensive list of 1056 keywords was obtained. Our MIS keyword list was compared with that of Barki and differences with Barkis list were identified, such as: (i) failing to include many keyword subjects that have frequently occurred during the past decade, and (ii) inclusion of keywords that have not had a single occurrence in MIS journals for the same period.

Combined optimal tuple ordering and attribute partitioning in storage schema design

Abstract Database operating efficiency in relational databases can be improved significantly by using proper storage schema. Two such methods to improve performance are attribute partitioning and record clustering. In the past, the two design problems were treated separately — the optimal attribute partitioning was obtained without considering the order in which tuples are laid out; this does not produce a true optimal solution. The paper provides experimental evidence that the best attribute partitioning scheme is dependent on the tuple ordering and vice versa. The combined optimal solution of attribute partitioning and tuple ordering obtained in the experiments showed an improvement in database operating efficiency ranging from 12% to 35%, compared to the independent optimal solutions of attribute partitioning and tuple ordering considered separately. This is of significance to the database designer interested in improving database operating efficiency.