In modern conditions, there is an active development of information systems of various levels. 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. Let's take a closer look at this area.
Design: general information
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 branches of human activity. A wide variety of tasks that are solved by means of IS leads to the emergence of different schemes. They differ in the principles of formation and data processing rules. The stages of designing information systems allow you to determine the way to solve problems that meets the requirements of the functionality of existing systems.technologies.
Main destinations
Design always starts with setting the goal of the future system. The main task of any scheme is to provide:
- Required functionality and level of adaptation to constantly changing conditions.
- Bandwidth.
- Response time to request.
- Reliability of work in the established mode.
- Easy to operate and maintain.
- Necessary security.
The project design stages cover:
- Data objects to be used in the database.
- Programs, reports, screen forms that provide the execution of requests.
- Accounting for a specific technology or environment (network topology, parallel or distributed 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 IS. This provision is considered fundamental and ensures objectivity. The system design stages involve a description of the requirements for IS with their subsequent transformation into a model structure. First, IS architecture diagrams are created. After that, the requirements for software and information support are formulated.
Define requirements
Steps in the design process associated with this task,considered to be the most responsible. Mistakes in the definition of requirements are difficult to correct. In addition, the subsequent adjustment is associated with significant costs. The tools that exist today make it possible to quickly create systems according to ready-made 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 the models. In this regard, each stage of system design must be accompanied by a thorough analysis.
Simulation
The main stages of design are accompanied by a deep study of the information, goals and objectives of IP. To form data models, experts use the results of the analysis. This design stage includes the construction of a logical and then a physical circuit. In parallel with this, the formation of operation models is carried out. They are necessary for the description (specification) of IS modules. The main stages of design - definition of requirements, modeling of operations and data - are closely interconnected. Part of the business logic is usually implemented in the details database (stored procedures, triggers, constraints). The main task that the operations design stage solves is the mapping of the functions that were obtained during the analysis into IS modules. When forming the latter, program interfaces are determined: 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 operating systems. There are heterogeneous ICs. In them, several computers run on different platforms, and management is carried out by different operating systems. The design phase involves the definition of a number of characteristics of the architecture. She can be:
- Client-server or file-server.
- Three-level, including several layers.
- Distributed or centralized. In the first case, mechanisms for maintaining relevance and consistency are additionally defined.
It also sets whether parallel servers will be used.
Shutting down
The design stage ends with the development of a technical plan for the IP. In the process of implementation, software for operational documentation is created. After the development of a single module is completed, a stand-alone test is performed. Required for:
- Fault detection (hard failure).
- Definitions of conformance to the specification (lack of unnecessary and presence of necessary functions).
After passing the test, the module is included in the developed part of the system. Then the connection tests are carried out. They are necessary to track the mutual influence of elements.
Control measures
Group of models tested for reliability. First of all, system failures are simulated. In addition, failure times are tested. In the first case, control measures allow you to determine how wellthe system recovers in the event of a software or hardware failure. According to the second group of tests, the level of IS stability is determined during regular work. These control measures allow to estimate the period of non-failure operation. The set of tests should also include those simulating the maximum load. After that, the entire complex of modules is subjected to system launch. In the course of it, internal acceptance control is carried out, which allows assessing its quality. During the evaluation, tests of the reliability and functionality of the system are carried out. The final control event is the acceptance test. In this case, the quality of the design stage at which the requirements were determined is manifested. During the test, the IP is demonstrated to the customer. During the demonstration, real operations are simulated, which illustrate the compliance of the project with the requirements of the customer.
Safety
Each IS must have certain collateral requirements:
- Protection against unauthorized access.
- Audit.
- Event registration.
- System Restore.
- Backup.
All these requirements are formalized by analysts at the beginning of the design. Specialists create an IP security strategy. They define the categories of users who have access to specific data through the respective components. Along with this, the subjects and objects of protection are established. It must be said that a security strategy should not be limited tosoftware. 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, highlight critical information, access to which will be strictly limited. System users are registered. In this regard, specialists are designing modules that will be responsible for the 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, views, tables. If you need to restrict access directly to the data itself, then you need to create a mandatory protection. In this case, individual records in tables, specific fields, and so on will be closed. System designers must be clear about what level of protection for a particular data item will be sufficient and what is necessary.
Conclusion
The stage of system design is considered one of the most important in the work on its creation. With him, in fact, the life of IP begins. Before designing, specialists must clearly define and understand the tasks that will be solved using the system, establish traffic flows, the physical location of resources and users, the method of connecting to the Internet, and so on. Of no small importance is the study of structures and buildings in which the network will be deployed, as well as an analysis of the existing infrastructure.
