問34
頻出度★★★
ソフトウェア保守の説明として, 適切なものはどれか。
平成24年度 春期 ITパスポート試験 問34
マネジメント系システム開発技術 › システム開発技術
This question's explanation and your answers so far.
解説
問 34
Incorrectア
“During system development, check whether each program created based on the detailed design contains errors, and correct them as needed” describes programming and unit testing (debugging) in the development phase. As the opening words “during system development” state explicitly, this is work done before live operation: errors built in before release are removed on the spot. Maintenance is an activity that changes the system after it is in operation, so the timing is decisively different. Even though “correcting errors” sounds similar, note that debugging during development is not maintenance.
- イ
正解 The correct answer is イ. Software maintenance is the activity of modifying and changing programs, data, and related documents after development has finished and the system has gone into live operation, so that the system can be kept in a usable state. It sits at the final stage of the software life cycle (planning → requirements definition → development → operation → maintenance), and it is generally the longest phase, taking up most of a system's lifetime. The reasons maintenance is needed can be organized into four points, and those points are exactly the categories of maintenance. First, corrective maintenance, which removes defects found after the system is in operation. Second, preventive maintenance, which deals in advance with latent faults that have not yet surfaced. These two correspond to “stable system operation” in choice イ. Third, adaptive maintenance, which fits the system to changes in the external environment, such as version upgrades of the OS, middleware, or hardware, and revisions of communication standards or laws. This corresponds to “advances in information technology.” Fourth, perfective maintenance, which improves performance and functions to raise usefulness when the way work is done changes or when new products and services must be handled. This corresponds to “changes in management strategy.” Choice イ lists all three of these motives and ends with “modify or change programs,” accurately stating the essence of maintenance: continuing to change the system after it is in operation. Therefore イ is appropriate.
Incorrectウ
“In response to inquiries from system users, record and manage the inquiry content, hand it over to the appropriate department, and record the results of the response” describes the service desk (help desk). In ITIL, the service desk acts as the single point of contact (SPOC) with users: it receives and records inquiries and incidents, escalates what it cannot solve itself to specialist departments, and records and reports the results of the response. This is user support in the operation stage, not an activity that modifies the programs themselves. It may hand work over to maintenance staff, but the side that hands the work over is not maintenance.
Incorrectエ
“Investigate the system from a broad perspective and judge whether it contributes to management” describes a system audit, or system evaluation (post-implementation evaluation of IT investment). In a system audit, an auditor in an independent position inspects and evaluates the system from viewpoints such as reliability, safety, and efficiency, and gives advice and recommendations to management; the deliverables are the evaluation and the report. It does not include the work of actually modifying or changing programs the way maintenance does. Tell them apart by asking whether the work is evaluating or actually going in and fixing.
ここがポイント
- Software maintenance is a phase that comes after the system is in operation — within the software life cycle (planning → requirements definition → development → operation → maintenance), it means modifying and changing programs after the system has gone into live operation. Debugging before live operation belongs to the development phase and is not maintenance; this split by timing is the biggest clue for telling them apart.
- The four types of maintenance and how to separate them from confusable roles — there is corrective maintenance, which removes defects found after the system is in operation; preventive maintenance, which heads off latent faults in advance; adaptive maintenance, which keeps the system in step with changes in the external environment such as the OS, hardware, or laws; and perfective maintenance, which raises functions and performance as work and management strategy change. The keywords “stable operation,” “advances in information technology,” and “changes in management strategy” map onto these. On the other hand, receiving, recording, and handing over inquiries is the service desk (help desk), and investigating and judging the contribution to management is a system audit or system evaluation. Cut the choices with the viewpoint that maintenance is the one that actually goes in and fixes the programs.
用語