Alan C. Benander

Data Warehouse Administration and Management

Abstract Data warehouses are huge repositories of legacy data. They are usually configured as stars or snowflakes, and their application strength is their ability to associate pieces of data in unique and multiple ways. Obviously, they are very different from traditional relational databases, and as such they require administrators that possess a skill set different from that of traditional database administrators. This article explores the skills a data warehouse administrator must possess.

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. >

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.

An empirical analysis of debugging performance — differences between iterative and recursive constructs

An experiment involving more than 500 responses from over 250 subjects was conducted for the purpose of identifying differences in debugging performance among subjects who debugged iterative code and those who debugged recursive code. The subjects, classified as novices or experienced, based on programming experience, were asked to locate and fix a single logical bug in small segments of C code. Two different tasks – searching a linked list and copying a linked list, were used in the experiment. Statistical analyses yielded the following significant results: (i) 63.2% of all subjects located the bug in the recursive constructs compared to 41.5% for the iterative constructs (p<.00001); (ii) Grouped by task, and level of programmer experience, there were significantly more correct responses for the recursive code than for the iterative code (p<.02 in all four groupings); (iii) In terms of locating and fixing the bug, more responses were correct for the recursive version of the copy task than for the iterative version (p=.01875). Results of a t-test procedure showed no significant difference between the iterative and recursive constructs in terms of mean times needed for successful completion of the debugging tasks.

Recursion vs. iteration: an empirical study of comprehension

Abstract An extensive study involving three test groups over a period of three different years was performed to determine differences between comprehension of recursive and iterative code constructs. This study involved computer science students enrolled in six different data structure classes using PASCAL and obtained 275 responses, which were statistically analyzed. Using a χ 2 test, one task—searching a linked list for a given value—showed a statistically significant ( p = 0.006) difference in comprehension favoring recursion. Another task—making a copy of a linked list—favored iteration, but not with statistical significance. Among responses with correct comprehension, a comparison of means test was performed on the comprehension times among the latter two groups in the study. There was a faster rate of comprehension of the recursive code for both of the tasks ( p = 0.096 for the search and p = 0.045 for the copy). A two-way analysis of variance suggested a tendency toward an interaction effect between task and construct in terms of comprehension time.

Factors related to the difficulty of learning to program in Java¿an empirical study of non-novice programmers

Abstract Due to its relative newness and popularity, Java is being taught to numerous non-novice programmers both in industry and in academia. Claims have been made that certain background characteristics of programmers relate to ease in learning Java. In this study, background information of 135 non-novice programmers was obtained, together with data relating to their difficulty of learning several different features of Java. Results of this study could be used by software project managers contemplating the use of Java, and by academicians involved in curricular planning.

An analysis of debugging techniques

AbstractAn empirical study of the use of debugging techniques among COBOL students was performed. Debugging time data for over 300 COBOL programs, together with information concerning use of debugging techniques was used in the analysis. Five debugging techniques were considered in this study: (a) COBOL debugging verbs and compiler options, (b) reading of system messages and basic JCL (Job Control Language), (c) reading of abnormal (ABEND) termination messages, (d) hand tracing, and (3) querying other programmers. Of pedagogical significance are results of the study which suggest the following: all of the debugging techniques will be used if students are made aware of them; students who spend the most time in debugging rely heavily on the use of debugging verbs, and use hand tracing less than all other groups of students; students who spend the least time in debugging will use a variety of debugging techniques, but rely most on hand tracing. Pedagogical approaches to the teaching of debugging skills are a...

Teaching Good Programming Style to COBOL Students

AbstractPedagogically significant results from an experiment which analyzed over 600 student COBOL programs for style provide evidence supportive of the use of good programming style. This paper presents some approaches which will aid instructors in the task of teaching good programming style to COBOL students. Specifically, the use of a style analyzer is discussed, a ranking of the style characteristics most often abused by COBOL students is presented, and classroom techniques for teaching good programming style are suggested.