In modern conditions, the active development of information systems at various levels is noted. All of them are implemented through the latest computer technology. Today, data processing acts as an independent direction of human activity. In this regard, the stages of designing information systems are of particular relevance. Consider this area in more detail.
Design: General
In today's world, data is considered one of the most important resources. Information systems, in turn, have become a necessary tool that is used in all areas of human activity. A lot of different tasks that are solved by means of IP, causes the emergence of different schemes. They differ in the principles of formation and data processing rules. The stages of designing information systems make it possible to determine a method for solving problems that meets the functionality requirements of existing technologies.
The main directions
Design always begins with setting the goal of a future system. The main task of any scheme is to ensure:
- The required functionality and level of adaptation to constantly changing conditions.
- Bandwidth.
- The response time to the request.
- Fail-safe operation in the established mode.
- Simplicity of operation and maintenance.
- The necessary security.
Project design steps include:
- Data objects to be used in the database.
- Programs, reports, screen forms that ensure the execution of queries.
- Accounting for a specific technology or environment (network topology, parallel or distribution processing, architecture, hardware, and so on).
Stages and design stages
The primary task of specialists is the modeling of operations through which the goals of the organization will be realized. The scheme allows you to define and formulate the main requirements for IP. This provision is considered fundamental and provides objectivity. The stages of system design involve a description of the requirements for IP with their subsequent transformation into a model structure. First, IP architecture designs are created. After that, the requirements for software and information support are formulated .
Definition of requirements
The stages of the design process associated with this task are considered the most responsible. Errors in determining requirements are difficult to fix. In addition, the subsequent adjustment is fraught with significant costs. The existing tools today allow you to quickly create systems according to ready-made requirements. However, often such IPs do not satisfy the customer; they need numerous improvements. This, in turn, leads to a sharp increase in the actual cost of the models. In this regard, each stage of system design should be accompanied by a thorough analysis.
Modeling
The main stages of design are accompanied by a deep study of information, goals and objectives of IP. To create data models, specialists use the results of the analysis. This stage of design includes the construction of a logical, and then a physical circuit. In parallel with this is the formation of models of operations. They are necessary for the description (specification) of IP modules. The main stages of design - the definition of requirements, modeling of operations and data - are closely interlinked. Part of the business logic, as a rule, is implemented in the database of information (stored procedures, triggers, restrictions). The main task that the design stage of operations solves is the mapping of functions that were obtained during the analysis into IP modules. When forming the latter, program interfaces are defined: the appearance of windows, menu layout, hot keys and calls associated with them.
Architecture
This design phase involves the selection of one or more platforms and OS. There are heterogeneous IP. They have several computers running on different platforms, and management is carried out by different OS. The design phase involves the identification of a number of architectural characteristics. She may be:
- Client-server or file-server.
- Three-level, including several layers.
- Distributed or centralized. In the first case, additional mechanisms for supporting relevance and consistency are additionally defined.
It also sets whether parallel servers will be used.
Shutdown
The design phase ends with the development of a technical plan for IP. In the process of implementation, software for operational documentation is created. After the development of a separate module is completed, an offline test is performed. It is necessary for:
- Failure detection (hard failure).
- Definitions of conformity to the specification (absence of unnecessary and availability of necessary functions).
After passing the test, the module is included in the developed part of the system. Then, link tests are performed. They are necessary to track the mutual influence of the elements.
Control activities
A group of models is tested for reliability. First of all, system failures are simulated. In addition, failure times are tested. In the first case, the control measures allow us to determine how well the system is restored in the event of a software or hardware failure. The second group of tests determine the level of stability of IP during regular work. These control measures allow you to evaluate the period of uptime. In the test suite should be present and simulating maximum load. After that, the entire complex of modules is subjected to system startup. During it, control of internal acceptance is carried out, allowing to evaluate its quality. During the assessment, tests of the reliability and functionality of the system are carried out. The final control measure is the acceptance test. In this case, the quality of the design stage is manifested, at which the requirements were determined. During the test, the IP is demonstrated to the customer. During the show, real operations are simulated, which illustrates the project's compliance with customer requirements.
Security
Each IP should have specific requirements for ensuring:
- Protection against unauthorized access.
- Audit
- Registration of events.
- System Restore.
- Backup.
All these requirements are formalized by analysts at the beginning of design. Specialists create an IP security strategy. They define the categories of users who have access to specific data through the relevant components. Along with this, subjects and objects of protection are established. It must be said that a security strategy should not be limited to software only. It should include a whole range of rules for conducting operations. It is necessary to clearly establish the optimal level of protection for each individual element, highlight critical information, access to which will be strictly limited. System users are registered. In this regard, specialists design modules that will be responsible for authentication and identification of subjects. In most cases, discretionary protection is implemented. It involves regulated access to certain data objects. It can be, for example, representations, tables. If you need to restrict access directly to the data itself, then you must create credential protection. In this case, individual entries in the tables, specific fields and so on will be closed. Specialists designing the system must clearly understand which level of protection for a particular unit of data will be sufficient and which is necessary.
Conclusion
The stage of system design is considered one of the most important in the work on its creation. From it, in fact, begins the life of IP. Before designing, specialists must clearly identify and understand the tasks that will be solved using the system, establish traffic flows, the physical location of resources and users, the way to connect to the Internet, and more. Of no less importance is the study of structures and buildings in which the network will be deployed, as well as an analysis of existing infrastructure.