What Are the Different Types of Maintenance Work?

In order to clear faults and errors that occur during system operation, software and hardware maintenance personnel must make necessary modifications and improvements to the system; in order to adapt the system to changes in the user's environment and meet new requirements, it is also necessary to make partial changes to the original system These tasks are called system maintenance. The task of system maintenance is to correct the hidden errors found during the use of the software system and expand the new functions and performance requirements put forward by the user during the use. The purpose is to maintain the "normal operation" of the software system. The documentation at this stage is a software problem report and a software modification report, which records the situations in which software errors are found and the process of modifying the software.

system maintenance

In order to clear faults and errors that occur during system operation, software and hardware maintenance personnel must make necessary modifications and improvements to the system; in order to adapt the system to changes in the user's environment and meet new requirements, it is also necessary to make partial changes to the original system These tasks are called system maintenance. The task of system maintenance is to correct the hidden errors found during the use of the software system and expand the new functions and performance requirements put forward by the user during the use. The purpose is to maintain the "normal operation" of the software system. The documentation at this stage is the software problem report and software modification report, which records the findings

The maintenance of the system is not only extensive, but also has many influencing factors. Generally, before carrying out a maintenance modification, the following three factors need to be considered:

Background of system maintenance

(1) Current situation of the system

(2) Maintenance object.

(3) The complexity and scale of maintenance work.

Impact of system maintenance work

(1) Impact on the goals of the new system.

(2) Impact on the current work progress.

(3) Impact on other parts of the system.

(4) Impact on other systems.

System maintenance resource requirements

(1) Time requirements for maintenance.

(2) The cost of maintenance (and whether it is cost-effective compared with the loss caused by no maintenance).

(3) Staff required for maintenance.

System maintenance organization management

System maintenance work is not just technical work. In order to ensure the quality of system maintenance work, a lot of management work is required. After the system is put into operation, in fact, the system maintenance work has begun before a specific maintenance request is made. System maintenance work must first establish a corresponding organization to determine the principles and standardized processes that should be followed for maintenance work. In addition, a set of documents and management measures applicable to the specific system maintenance process and standards for review should be established. After the information system is put into operation, a system maintenance manager should be set up to be responsible for the management of the entire system. For each subsystem or function module, a system manager should be equipped. Their task is to familiarize and carefully study the functions of some systems The implementation process, and even a clear understanding of the program details, in order to complete the specific maintenance work. The requirements for system change and maintenance often come from a part of the system, and whether such maintenance requirements are reasonable for the entire system, to what extent should be met, and a trade-off should be made from a global perspective. Therefore, in order to coordinate and review the maintenance work from a global perspective, each maintenance requirement must be reviewed and approved by a maintenance control department before it can be implemented. It is a maintenance control department and should be composed of business departments and system management departments. In order to control the rationality and feasibility of the maintenance content from the perspective of business functions and technical realization. The organization and management of the system is shown in Figure 1:

Structure chart of system maintenance organization management 1

Procedure of system maintenance work Figure 2:

Procedure of system maintenance work Figure 2

Each maintenance request of the user is submitted to the maintenance administrator in a written "Maintenance Request Report". For error-correcting maintenance, the report must fully describe the environment in which the error occurred, including input data, output data, and other system status information; For adaptive and comprehensive maintenance, a brief requirements specification should be presented in the report. Based on the application submitted by the user, the maintenance administrator must convene the relevant system administrator to verify and evaluate the content of the maintenance application report. For actual and reasonable maintenance requirements, a maintenance report should be prepared based on the nature, content, estimated workload, emergency procedures or priorities, and changes resulting from the modification, etc., and submitted to the maintenance control department for approval. The maintenance control department starts from the entire system, analyzes and reviews the maintenance requirements from the aspects of business function rationality and technical feasibility, and makes a full estimate of the impact of the modification. For inappropriate maintenance requirements, it is negotiated with the user. To be modified or revoked. Approved maintenance reports allow maintenance managers to formulate maintenance plans based on specific conditions. For error-corrective maintenance, estimate its urgency. If the maintenance is very urgent and seriously affects the operation of the system, it should be arranged to start the modification work immediately; if the maintenance is not serious, it can be combined with other maintenance projects to coordinate the maintenance and development resources ; For adaptive or complete maintenance requirements, a high priority is arranged in the maintenance plan, and the low priority can be considered as a new development project organization development. The contents of the maintenance plan shall include: the scope of maintenance work, the required resources, the confirmed requirements, maintenance costs, maintenance schedules, and acceptance criteria. The maintenance administrator issues the maintenance plan to the system administrator, and the system administrator plans to make specific modifications. Modifications should undergo rigorous testing to verify the quality of maintenance work. After the test is passed, the user and the management department will review and confirm it, and it cannot be fully reworked and modified. Only the confirmed maintenance results can update the corresponding documents of the system and finally deliver them to users.

All system maintenance must be carried out in strict steps to prevent unauthorized modification of the system, because whether the user directly finds the programmer or the programmer to modify the program by himself, it will cause system confusion. The program is inconsistent with the document, the results of multiple people's modification are inconsistent, and the local modification lacks global considerations. Of course, too many links in the maintenance approval process may also result in a slow response time. Therefore, when a system has a malignant or emergency failure, the so-called "fire fighting" maintenance requirement is that resources must be immediately used to solve the problem to ensure the continuity of business get on.

In order to evaluate the effectiveness of maintenance, determine the quality of the system, and record the maintenance content experienced by the system, the entire content of the maintenance work should be recorded in a standardized form of the document, mainly including the maintenance object, scale, language, operation, and error occurrence. As a part of the system development document, the historical situation, the modification made by maintenance, and the price paid for maintenance are formed into historical data for future reference.

Maintaining the old means modifying the system. Modifications have some side effects on the system, that is, errors or other undesired behaviors due to the modification. This side effect mainly comes from three aspects: first, the modification of the source code may Introducing new errors, such side effects can generally be found through regression testing. Second, data structure modifications, such as redefinition of local or global variables, modification of file formats, etc., may cause errors such as data mismatch. When modifying, you must refer to the detailed description of the data structure in the system file and the data cross-reference table between modules to prevent local changes from affecting the overall global effect. Third, any modification to the source program, such as the corresponding document Updates will cause inconsistencies between the source program and the documentation, and will confuse future applications and maintenance. In system maintenance, you should pay attention to the above 3 issues to avoid side effects caused by modification.

In addition, when arranging the work of system maintenance personnel, it should be noted that not only must each person's maintenance responsibilities be clear, but at least two people should be arranged for each subsystem or module to carry out maintenance work. This can avoid system maintenance work for someone Over-reliance on maintenance to prevent maintenance work from being affected due to work transfer and other reasons. The stability of the maintenance personnel team should be maintained as much as possible. When the system operation has not exposed problems, maintenance personnel should focus on being familiar with the relevant documents of the system and understanding the functions The implementation process of the procedures, once the maintenance requirements are raised, they should complete the maintenance work quickly and with high quality.

Finally, attention should be paid to the limits of system maintenance. System maintenance is based on the modification, adjustment and improvement of the original system. Make the system continuously adapt to the new environment and new needs. But at the end of the life cycle of a system, when the modification of the system no longer works, or the modification is difficult and the workload is large, the cost is too large, and the content of improvement and perfection far exceeds the original system design At that time, the requirement of developing a new system should be put forward, thereby starting a new system life cycle.