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Stages and stages of design. Main Stage of Design

In modern conditions there is an active development of information systems of different levels. All of them are implemented through modern computer technology. Today, data processing acts as an independent direction of human activity. In this connection, the stages of designing information systems acquire special relevance. Let's consider this sphere in more detail.

Designing: general information

In today's world, data is considered one of the most important resources. Information systems, in turn, have turned into a necessary tool that is used in all fields of human activity. A lot of various tasks that are solved by means of IP, causes the emergence of different schemes. They differ in the principles of formation and rules of data processing. The stages of the design of information systems allow us to determine the method of solving problems that meets the requirements of the functionality of existing technologies.

Main directions

Design always begins with establishing the purpose of the future system. The main task of any scheme is to ensure:

  1. Required functionality and level of adaptation to constantly changing conditions.
  2. Bandwidth.
  3. The response time to the request.
  4. Trouble-free operation in the established mode.
  5. Simplicity of operation and maintenance of working capacity.
  6. Necessary security.

The stages of project design cover:

  1. Data objects that will be used in the database.
  2. Programs, reports, screen forms, providing the execution of requests.
  3. Accounting for a particular technology or environment (network topology, parallel or distribution processing, architecture, hardware, and so on).

Stages and stages of design

The primary task of specialists is modeling operations, through which the goals of the organization will be realized. The scheme allows to define and formulate the main requirements for IP. This provision is considered fundamental and provides objectivity. The stages of the system design assume the description of the requirements for the IC with the subsequent transformation of them into a model structure. First, schemes of the IP architecture are created. After this, the requirements for software and information support are formulated .

Definition of requirements

The stages of the design process associated with this task are considered to be the most responsible. Errors in determining requirements are difficult to fix. In addition, subsequent adjustment is costly. Existing tools today allow you to quickly create systems for already ready requirements. However, often such ICs do not satisfy the customer, they need numerous improvements. This, in turn, leads to a sharp increase in the actual cost of 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 generate data models, specialists use the results of the analysis. This stage of design involves the construction of a logical, and then a physical scheme. Simultaneously, formation of models of operations is carried out. They are necessary for the description (specification) of the IC modules. The main stages of design - the definition of requirements, modeling of operations and data - are closely interrelated. 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 the functions that were obtained during the analysis to the IC modules. When creating the latter, the program interfaces are defined: the type of windows, menu layout, hot keys and calls associated with them.

Architecture

This design stage involves selecting one or more platforms and operating systems. There are heterogeneous ICs. They have several computers running on different platforms, and the management is performed by different OSes. The design phase involves determining a number of characteristics of the architecture. She may be:

  1. Client-server or file-server.
  2. Three-level, including several layers.
  3. Distributed or centralized. In the first case, mechanisms for maintaining relevance and consistency are additionally defined.

It is also established whether parallel servers will be used.

Shutdown

The design phase ends with the development of the 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 autonomous test is performed. It is necessary for:

  1. Failure detection (hard failure).
  2. Determination of compliance with the specification (the absence of unnecessary and the availability of necessary functions).

After passing the test, the module is included in the developed part of the system. Then the bond tests are conducted. They are needed to track the mutual influence of the elements.

Control measures

The model group is tested for reliability. First of all, system failures are simulated. In addition, MTBFs are tested. In the first case, control measures can reveal how well the system is recovering in the event of a software or hardware failure. The second group of tests determine the level of stability of the IP in the course of regular work. These control measures make it possible to assess the period of failure-free operation. In the set of tests should be present and simulating the maximum load. After that, the whole complex of modules undergoes a system start-up. During it, the internal acceptance control is carried out, allowing to estimate its quality. During the evaluation, tests are carried out on the reliability and functionality of the system. The final control measure is the acceptance test. In this case, the quality of the design phase is manifested, on which the requirements were determined. During the test, the IS is demonstrated to the customer. During the show, real operations are simulated, which illustrate the suitability of the project to the customer's requirements.

Security

In each IP there should be certain requirements for ensuring:

  1. Protection against unauthorized access.
  2. Audit.
  3. Event recording.
  4. System Restore.
  5. Backup.

All these requirements formalize the analysts at the beginning of the design. Experts 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 the security strategy should not be limited only to software. It should include a whole set of rules for conducting operations. It is necessary to clearly establish the optimal level of protection for each individual element, to allocate critical information, access to which will be strictly limited. Users of the system are registered. In this regard, specialists design modules that will be responsible for the authentication and identification of subjects. In most cases discretionary protection is realized. It involves regulated access to certain data objects. This can be, for example, views, tables. If you want to restrict access directly to the data itself, you must create a mandatory protection. In this case, individual records in the tables, specific fields, and so on will be closed. Specialists who design the system should clearly represent exactly what level of protection a specific data unit will be sufficient, and which is necessary.

Conclusion

The design phase of the system is considered one of the most important in the work on its creation. From it, in fact, the life of IP begins. Before designing, specialists must clearly define and understand the tasks that will be solved by the system, establish traffic flows, the physical location of resources and users, the way to connect to the Internet, and so on. Of no small importance is the study of structures and buildings in which the network will unfold, as well as an analysis of the existing infrastructure.

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