Software and technical systems for implementing information processes. Computer science test “Software and hardware systems for implementing information processes. Implementation of information systems

6. Development and implementation of an information system

6.1. Principles of creating an information system

Many users of computer hardware and software have repeatedly encountered a situation where software that works well on one computer does not work on another similar device. Or the system units of one computing device do not interface with the hardware of another. Or the information system of another company stubbornly refuses to process the data that you prepared in the information system at your workplace. This problem is called the problem of compatibility of computing, telecommunications and information devices.

The development of computer systems and tools, their expanded implementation in all areas of science, technology, services and everyday life have led to the need to combine specific computing devices and information systems implemented on their basis into unified information and computing systems (ICS) and environments. At the same time, IVS developers faced a number of problems.

For example, the heterogeneity of technical means of computer technology in terms of the organization of the computing process, architecture, command system, processor bit capacity and data bus, etc. required the creation of physical interfaces that, as a rule, implement mutual compatibility of devices. With an increase in the number of types of integrated devices, the complexity of organizing the physical interface between them increased significantly. The heterogeneity of programmable environments implemented in specific computing devices and systems, in terms of the variety of operating systems, differences in bit depth and other features, has led to the creation of software interfaces between devices and systems. It should be noted that it was not always possible to achieve full compatibility of software products developed for a specific software environment in another environment. The heterogeneity of communication interfaces in the human-computer system required constant coordination of software and hardware and retraining of personnel.

The principle of "openness" of the information system

Solving compatibility problems has led to the development of a large number of international standards and agreements in the field of application of information technologies and development of information systems. The fundamental concept has become the concept of open systems.

The term "open system" can now be defined as "a comprehensive and consistent set of international information technology standards and functional standards profiles that specify interfaces, services and their supporting formats to enable interoperability and mobility of software applications, data and personnel."

This definition, formulated by specialists from the IEEE (Institute of Electrical and Electronic Engineers), unifies the content of the environment that an open system provides for widespread use. Currently, the generally recognized coordination center for the development and harmonization of open systems standards is OASIS (Organization for the Advancement of Structured Information Standards).

The general properties of open information systems can be formulated as follows:

extensibility/scalability: providing the ability to add new IS functions or change some existing ones, while leaving the remaining functional parts of the IS unchanged;

mobility/portability: ensuring the ability to transfer programs and data when upgrading or replacing hardware IS platforms and the ability for specialists using IT to work with them without retraining them when changing the IS;

interaction: the ability to interact with other information systems (the technical means on which the information system is implemented are united by a network or networks of various levels: from local to global);

standardizability: IS are designed and developed on the basis of agreed international standards and proposals, openness is implemented on the basis of functional standards (profiles) in the field of information technology;

user friendliness: developed unified interfaces in interaction processes in the “man-machine” system, allowing a user who does not have special “computer” training to work.

A new look at open systems is determined by the fact that these features are considered together, as interrelated, and are implemented in a complex, which is quite natural, since all the above properties complement each other. Only together, the capabilities of open systems make it possible to solve the problems of design, development and implementation of modern information systems.

Structure of the information system environment

The generalized structure of any IS can be represented by two interacting parts:

functional part, including application programs that implement the functions of the application area;

environment or system part that ensures the execution of application programs.

Two groups of standardization issues are closely related to this division:

standards for interfaces between application programs and the IS environment, Application Program Interface (API);

standards for interfaces between the IS itself and its external environment (External Environment Interface - EEI).

These two groups of interfaces define the specifications of the external description of the IS environment - the architecture, from the point of view of the end user, the IS designer, and the application programmer developing the functional parts of the IS.

Specifications of external interfaces of an IS environment and, as will be seen below, specifications of interaction interfaces between components of the environment itself are precise descriptions of all necessary functions, services and formats of a specific interface. The set of such descriptions constitutes the Reference Open System Model.

This model has been in use for over 20 years and is defined by the Systems Network Architecture (SNA) proposed by IBM in 1974. It is based on dividing the computing environment into seven levels, the interaction between which is described by the corresponding standards, and ensures the connection of the levels regardless of the construction of the level in each specific implementation (Fig. 6.1). The main advantage of this model is a detailed description of connections in the environment from the point of view of technical devices and communication interactions. However, it does not take into account the interconnection taking into account the mobility of application software.

Rice. 6.1.

The Open Systems Environment Reference Model (OSE/RM) defines the division of any information system into applications (application programs and software systems) and the environment in which these applications operate. Standardized interfaces (APIs) are defined between applications and the environment and are a necessary part of the profiles of any open system. In addition, in IS profiles, unified interfaces for interaction of functional parts with each other and interaction interfaces between components of the IS environment can be defined.

Model for creating an information system

Methodologically, it is important, along with the considered models of the IS environment, to propose a model for creating an IS that would have the same aspects of functional groups of components (users, functions, data, communications). This approach will provide an end-to-end process of design and support at all stages of IS operation and the possibility of an informed choice of standards for system development and project documentation.

A company is a complex ontological (conceptual) structure, consisting of a certain set of entities and relationships (Fig. 6.2).

Rice. 6.2.

The interactions between its elements, determined by business logic and enshrined in a set of business rules, are the activities of the company. The information system “reflects” logic and rules, organizing and transforming information flows, automating the processes of working with data and information, and visualizing the results in the form of sets of reporting forms. Therefore, first you should create a business model of the enterprise, which is a reflection of the enterprise and its information management system.

When creating a model, a “language of communication” is formed between enterprise managers, consultants, developers and future users, which allows them to develop a unified idea of WHAT and HOW an enterprise management system (corporate management system) should do. Such a business model is a tangible result, with the help of which you can specify the goals of IS implementation as much as possible and determine the following project parameters:

main business goals that can be achieved through process automation;
list of sites and sequence of implementation of IS modules;
actual need for volumes of purchased software and hardware;
real estimates of the timing of deployment and launch of the IMS;
key users of the IS and an updated list of implementation team members;
the degree of compliance of the application software you choose with the specifics of your company’s business.

The model is always based on the business goals of the enterprise, which completely determine the composition of all the basic components of the model:

business functions, which describe WHAT the business does;
core, support and management processes that describe HOW the enterprise performs its business functions;
organizational and functional structure that determines WHERE business functions and business processes are performed;
phases that determine WHEN (in what sequence) certain business functions should be implemented;
roles that determine WHO performs business functions and WHO is the “master” of business processes;
rules that define the connection and interaction between all the WHAT, HOW, WHERE, WHEN and WHO.

After building a business model (or in parallel with this), you can begin to form a model for the design, implementation and implementation of the IS itself (Fig. 6.3).

Rice. 6.3.

The experience of creating and using “custom” IS allows us to roughly identify the following main stages of their life cycle:

defining system requirements and analyzing them - determining what the system should do;
design - determining how the system will do what it is supposed to do; design is, first of all, a specification of subsystems, functional components and ways of their interaction in the system;
development - creation of functional components and individual subsystems, connection of subsystems into a single whole;
testing - checking the functional compliance of the system with the indicators determined at the analysis stage;
implementation - installation and commissioning of the system;
operation - the normal process of operation in accordance with the main goals and objectives of the IS;
support - ensuring the normal process of operating the system at the customer’s enterprise.

Determining system requirements and analysis is the first stage of creating an IS, at which the customer's requirements are clarified, agreed upon, formalized and documented. In fact, at this stage the answer to the question is given: “What is the information system intended for and what should it do?” This is where the key to the success of the entire project lies.

The goal of systems analysis is to transform general, vague knowledge about the original domain (customer requirements) into precise definitions and specifications for developers, as well as generating a functional description of the system. At this stage, the following are determined and specified:

external and internal operating conditions of the system;
functional structure of the system;
distribution of functions between a person and the system, interfaces;
requirements for technical, information and software components of the system,
quality and safety requirements;
composition of technical and user documentation;
conditions of implementation and operation.

The development of the above specifications when creating an IS intended to automate management processes generally goes through four stages.

The first stage of analysis - structural analysis of the enterprise - begins with a study of how the enterprise management system is organized, with an examination of the functional and information structure of the management system, and identification of existing and possible consumers of information.

Based on the results of the survey, the analyst at the first stage builds a generalized logical model of the original subject area, reflecting its functional structure, features of the main activity and the information space in which this activity is carried out (Fig. 6.4). Based on this material, the analyst builds a functional model “As Is” (As Is).

The second stage of work, in which interested representatives of the customer, and, if necessary, independent experts, are necessarily involved, consists of analyzing the “As Is” model, identifying its shortcomings and bottlenecks, and identifying ways to improve the management system based on the identified quality criteria.

The third stage of analysis, containing design elements, is the creation of an improved generalized logical model that displays the reorganized subject area or part of it that is subject to automation - the “As To Be” model.

The process (fourth stage) ends with the development of an “Automation Map”, which is a model of a reorganized subject area, on which the “automation boundaries” are necessarily indicated.

In most cases, the “As Is” model is improved by a systems analyst by eliminating obvious inconsistencies and bottlenecks, and the thus obtained version of the model is considered further as a preliminary “As It Should Be” model, which is subsequently supplemented in accordance with the enterprise development strategy (Fig. .6.5).

Rice. 6.5.

At the stage of analyzing the requirements for the designed system, the following are introduced:

user classes and corresponding business transaction diagrams;
models (diagrams) of applied activity processes and corresponding lists of functional IS tasks;
classes of domain objects and corresponding entity-relationship diagrams reflecting the information model of this subject domain;
topology of the location of departments and users served by this IS;
parameters for protecting data, information and the system itself.

The main document reflecting the results of the first stage of creating an IS is the terms of reference for the project (development), which contains, in addition to the above definitions and specifications, also information about the order of creation of the system, information about allocated resources, target dates for individual stages of work, organizational procedures and activities for acceptance of stages, protection of design information, etc.

The next stage is design. In real conditions, design is a search and modeling of a development method that satisfies the requirements of the system functionality using available technologies, taking into account the given initial conditions and restrictions. Information systems design always begins with defining the purpose of the project. The main task of any successful project is to ensure that at the time of system launch and throughout its operation it is possible to ensure:

the required functionality of the system and the degree of adaptation to the changing conditions of its operation;
required system throughput and minimum system response time to a request;
trouble-free operation of the system in the required mode, readiness and availability of the system to process user requests;
ease of operation and maintenance of the system;
necessary data security and user access rights.

Performance and reliability are the main factors determining the effectiveness of the system. Good design is the foundation of a high-performance system.

Information systems design covers three main areas:

designing data structures that will be implemented in the database;
designing programs, screen forms, reports that will ensure the execution of data queries;
design of a specific environment or technology, namely: network topology, hardware configuration, architecture used, parallel processing, distributed data processing, etc.

Based on the results of the system analysis at the preliminary project stage, the following are developed:

software and hardware implementation project, user interface project and technology for users to work in the system;
distributed system architecture and telecommunications network specifications;
data flow models (diagrams);
functional block diagrams of application and system software (the latter in accordance with accepted IS environment models and standards profiles).

The preliminary design stage may involve prototyping parts that are important from the user's point of view to test their compliance with requirements early in the development phase.

At the detailed design stage the following are developed:

complexes of functional IS programs and the project for implementing the IS environment;
data structures, database maintenance tools;
network addresses, telecommunication protocols and other components of the information exchange environment included in the designed IS;
rules for limiting user access and means of their implementation.

The IS implementation stage involves the development and testing of components and comprehensive testing of the system.

The operation and maintenance stage involves monitoring the functioning of the IS, making the required changes to the information base in the process of ongoing work and upgrading the IS functions by application specialists using tools built into the system.

The stages of development, testing, implementation, operation and maintenance of an IS are united by the term implementation. Implementation of IP is an extremely complex multidimensional process carried out on the basis of sets (profiles) of harmonized international standards, specifications and agreements. This practice is a guarantee that the created information system will be implemented as an “open system”. In other words, such an IS will be scalable, mobile, portable, have user-friendly interfaces, etc.

The life cycle of an information system is formed in accordance with the principle of top-down design and, as a rule, is of a spiral-iterative nature. The implemented stages, starting from the earliest ones, are repeated cyclically in accordance with changes in requirements and external conditions, the introduction of additional restrictions, etc. At each stage of the life cycle, a certain set of technical solutions and documents is generated, and for each stage the initial documents and solutions are , adopted at the previous stage. The life cycle of an information system ends when its software and technical support ceases.

6.2. Business process reengineering

The introduction of information technologies and information systems implemented on their basis into the daily activities of an enterprise gives it tactical and long-term business advantages. Management's desire to use IT can remain only good intentions if it does not follow the established requirements and rules for the development, design and implementation of IT. Above we talked about the basic requirements for the standardization of objects and functional tasks, without which the implemented system will not be an open system, which will subsequently lead to numerous problems during its implementation and operation.

Following the requirements of standards when developing an IS automatically leads to the fact that the enterprise itself - the external environment for the IS - also meets the necessary requirements: definition and standardization of classes of users and objects, topology of data flows and work, architecture of inherited and developed subsystems, state of business processes and etc.

A business process is a system of sequential, purposeful and regulated activities in which, through control actions and with the help of certain resources, over a certain time, process inputs are converted into outputs - into results that are valuable to the consumer and bring profit to the manufacturer.

A standard enterprise-wide business process is implemented as a network of main, auxiliary, supporting and management processes (Fig. 6.6).

Rice. 6.6.

At the same time, the division into main and auxiliary processes depends to a certain extent on the subject area and direction of the enterprise’s activity: for a manufacturing company, for example, the activities of the legal department are auxiliary, and for a legal or consulting firm they are the main ones. Identification of processes is a prerequisite, without the implementation of which informatization of activities is impossible.

Enterprise managers who have decided to implement IT must firmly understand that the beginning of work on designing an information system most often entails mandatory reengineering of business processes! Reengineering consists of many methods and recommendations, among them you need to choose those that best satisfy your goals.

Business process reengineering is a set of methods and actions used to redesign processes in accordance with changed conditions of the external and internal environment and/or business goals.

There are several basic rules that should be followed during the reengineering process:

development of consistent step-by-step procedures for process redesign;
use of standard languages and notations in design;
the presence of heuristic and pragmatic indicators that allow assessing or measuring the degree to which the redesigned process or functionality meets the specified goals;
the approach to solving particular problems and their totality should be systematic;
even a small improvement should have a quick positive effect.

Reengineering of business processes and functions begins with a review of the goals of the enterprise, its structure, analysis of the needs of internal users and the market, products and services produced (Fig. 6.7).

Replanning goals and objectives involves revising the enterprise's policy and answering the following questions:

What new challenges do the changed business conditions present us with?
What does the enterprise represent now, and what do we want from it in the future?
What kind of consumers do we serve, how much do we satisfy their requirements and expectations, and what needs to be done to attract new ones?
What specific indicators determine the efficiency of an enterprise, labor productivity and product quality? Is this definition complete and adequate?
What information technologies and tools will help us with this?

Rice. 6.7.

To answer these key questions, it is necessary, first of all, to carry out a detailed description of the business architecture of the enterprise, its business logic, build a functional model of the interaction of business processes, resources and personnel and reflect it in the IS architecture, the content of modules of information subsystems and visualization of information presentation forms . It is also necessary to have methods and tools for reorganizing processes, solving applied problems and managing a reengineering project (Fig. 6.8). Description of the enterprise business architecture allows you to:

build a diagram of the main flows of data, work, movement of finances and documents;
understand how information is distributed between departments and who the end user is in a particular business process;
describe the interaction of processes and modules of the information system;
determine the critical importance of types of information for specific levels of enterprise management;
identify duplicate structures and connections.

Rice. 6.8.

The result of this description is:

refined process network map;
matrix of relationships between processes and departments involved in these processes;
information about what automation systems exist, in what operations they are used, where and what data is used, what automation and information systems need to be developed;
functional diagrams of data flows (Data Flow), work flows (Work Flow), financial flows (Cash Flow), management impact flows (Control Flow) and document flow (Doc Flow).

A functional model will help to create precise specifications of all operations, procedures and relationships between them. Such a model, if constructed correctly, provides a comprehensive description of the functioning process and all the information flows within it. This model describes the “As Is” state. Based on the results of the analysis of possible ways of improvement, it is necessary to move from the real model to a model that characterizes improvements - the “As To Be” model, option - “As It Should Be” (Fig. 6.9).

Rice. 6.9.

Functional modeling is a rather serious problem; the completeness and compliance of the constructed model depend both on the modeling tools and on the qualifications of the specialists performing this modeling.

Business process reengineering is a complex and multifaceted project that requires careful planning and elaboration of details. Table 6.1 shows the main stages of reengineering.

Table 6.1. Main stages of reengineering

Stage	Events
Planning and starting work	Identifying the main reasons for carrying out reform at an enterprise and assessing the consequences of abandoning such reform
	Identification of critical processes requiring reengineering
	Identifying like-minded people among management and creating a working group of administration representatives
	Ensure management support for the project
	Preparing a project plan: defining the scope, identifying measurable goals, choosing a methodology, drawing up a detailed schedule
	Coordination of project goals and scope with management
	Formation of a reengineering group
	Selecting consultants or external experts
	Conducting an introductory meeting
	Communicating project goals to lower-level managers; initial communication to the entire organization
	Reengineering team training
	Preparing a plan and starting work
Research	Analytical study of the experience of companies with similar processes
	Survey customers and control groups to identify existing and future requirements
	Interview employees and managers to identify issues; brainstorm
	Searching the literature and press for data on industry trends and other people's experiences
	Preparation of detailed documents for initial processes and collection of operational data; identifying deficiencies
	Overview of Technology Changes and Options
	Survey of owners and management representatives
	Attending clubs and seminars
	Collecting data from external experts and consultants
Design	Brainstorming and developing innovative ideas; Creative thinking exercises to "take off your blinders"
	Working through “what if” scenarios and applying the “patterns of success” of other companies
	Creation of 3-5 models with the help of specialists; development of complex models that combine the best from each of the previous ones
	Creating a Picture of the Ideal Process
	Definition of new process models and their graphical representation
	Development of an organizational model in combination with a new process
	Determination of technological requirements; choosing a platform for new processes
	Distinguishing short-term and long-term measures
Statement	Cost-benefit analysis; calculation of return on capital
	Assessing the impact on clients and employees; assessment of impact on competitiveness
	Preparation of a white paper for senior management
	Conducting review meetings to review and approve project details by the organizing committee and senior management
Implementation	Completion of detailed development of processes and organizational models; defining new job responsibilities
	Development of support systems
	Implementation of preliminary options and initial tests
	Introducing employees to the new option; development and implementation of a reform plan
	Development of a phased plan; implementation as such
	Development of a training plan; training employees in new processes and systems
Follow-up events	Development of periodic assessment activities; determining the outcome of the new process; implementation of a continuous improvement program for the new process
Follow-up events	Submission of the final report to the organizing committee and administration

6.3. Process mapping and modeling

Today, three main functional modeling methodologies (and their accompanying tools) have become widespread: IDEF (Integrated DEFinition), UML (Unified Modeling Language) and ARIS (Architecture of Integrated Information Systems). For each of them, there are certain software products that, in addition to development, allow you to carry out transformations and operations for subsequent work with the resulting models. The most widely used today are the IDEF methodologies and the BPWin software product, which contains the IDEF0, IDEF3, DFD (Data Flow Diagrams) and ERWin (IDEF1x) methodologies from Computer Associates.

The history of the IDEF methodology begins in the 70s of the twentieth century with the SADT (Structured Analysis and Design Technique) methodology developed by Douglas Ross (Softtech INC). SADT was initially used by the US Department of Defense for practical process modeling as part of the ICAM (Integrated Computer Aided Manufacturing) program. The fundamental requirement when developing the family of methodologies under consideration was the possibility of effective exchange of information between all specialists participating in the ICAM program (Icam DEFinition). This methodology was subsequently transformed into the IDEF0 (Function Modeling, FIPS No. 183) standard. The IDEF family includes the already mentioned IDEF3 (Process Description Capture) and IDEF1x (Data Modeling, FIPS No. 184).

After the publication of the standards, they were successfully applied in a variety of areas of business, showing themselves to be an effective means of analyzing, designing and displaying business processes (by the way, it is also actively used in domestic government agencies, for example, in the State Tax Inspectorate). Moreover, the widespread use of IDEF (and the previous SADT methodology) is responsible for the emergence of the basic ideas of the now popular concept of “Business Process Reengineering” (BPR).

The information process is a sustainable process (a sequence of works and actions with data and information) related to the support of the production and economic activities of a company and usually focused on information services for creating new value. A business process includes a hierarchy of interrelated functional activities that implement one (or several) business goals of the company and reflect the results in the information system, for example, information support for the management and analysis of product output or resource support for product output (products here mean goods, services , decisions, documents).

Working with the IDEF method begins with setting a modeling goal. World experience shows that errors in goal setting lead to an average of 50% failures in the modeling process. Formulating a goal initially directs work in a given direction, and therefore limits the range of questions for analysis. Practical work begins with defining the context (Context, Context Diagram), that is, the top level of the system, in our case, the enterprise. After formulating the goal, it is necessary to outline the modeling area (Scope), which will subsequently determine the general directions of movement and the depth of detail (Decomposition). Actually, the IDEF methodology itself defines standardized objects for operation and display. For example, these include a function (Activity), an interface arc (Arrow), a note (Note), as well as the method of their location and interpretation (Semantics).

Recently, the Business Studio software product has appeared on the Russian market, which is specially created to work with IDEF methods and has an intuitive and user-friendly interface.

Rice. 6.10.

The IDEF0 notation and methodology is based on the concept of a “block,” that is, a rectangle that expresses a certain business function (Figure 6.10). In accordance with the standard, a function must be expressed by a verb phrase. In IDEF0, the roles of the sides of the rectangle (functional meanings) are different: the top side has the meaning “control”, the left side means “input”, the right side means “output”, the bottom side means “execution mechanism”.

The second element of the methodology and notation is the “flow”, called the “interface arc” in the standard. This is an element that describes data, informal control, or anything else that influences the function depicted by the block. Streams are indicated by a noun phrase.

Depending on which side of the block the flow is directed to, it is, accordingly, called “input”, “output”, “control”. The figurative element representing flow is an arrow. A stream can be interpreted as a representation of an object, which refers to both an information object and an actual physical object.

An important factor is that the “source” and “destination” of flows (that is, the beginning and end of the arrow) can, as a rule, only be blocks. In this case, only the output side of the block can be the source, and any of the remaining three can be the receiver. If it is necessary to emphasize the external nature of the flow, then the “tunneling” method can be used - hiding or appearing the interface arc from the “tunnel”.

And finally, the “third pillar” of the IDEF0 methodology is the principle of functional decomposition of blocks, which is a model interpretation of the practical situation that any action (especially something as complex as a business process) can be broken down (decomposed) into simpler operations ( actions, business functions). Or, in other words, an action can be represented as a set of elementary functions.

An example of a functional model of the process of shipment and delivery of products is shown in Fig. 6.11.

The degree of formalization of the description of business processes may vary depending on the tasks being solved. A specialized language BPEL (Business Process Execution Language) has been developed to describe information processes. BPEL is based on XML to formally describe business processes and protocols for their interaction with each other. BPEL extends the Web services interaction model to include transaction support.

Currently, the BPMS (Business Process Management System) methodology is actively developing - a class of software for managing business processes and administrative regulations. (The terms BPM system and simply BPM are also used). Using BPMS allows you to organize effective interaction between managers and IT specialists, make better use of existing subsystems and speed up the development of new ones.

The main functions of BPMS are modeling, execution and monitoring of business processes. Based on monitoring data, enterprises identify bottlenecks and improve their business processes. The management cycle is closed when, with the help of BPMS, changed business processes are quickly put into operation.

Modern methods of designing and developing IS software are trying to fully focus on the possibilities of automated, operational changes. The most difficult process turned out to be the standardization of the BPEL language to unify the use of the same constructs by software from different manufacturers. IBM and Microsoft have defined two quite similar languages: WSFL (Web Services Flow Language) and Xlang, respectively.

The growing popularity of BPML and the open movement of BPMS to users led Intalio Inc., IBM and Microsoft to the decision to combine these languages into a new language BPEL4WS. In April 2003, BEA Systems, IBM, Microsoft, SAP and Siebel Systems contributed BPEL4WS version 1.1 to OASIS for standardization in the Web Services BPEL Technical Committee. Although BPEL4WS appeared in versions 1.0 and 1.1, the WS-BPEL OASIS technical committee voted on September 14, 2004 to call the specification WS-BPEL 2.0. This change was made to align BPEL with other Web services standards that, based on the Naming Convention, begin with the letters "WS-".

Active Endpoints Corporation, Adobe, BEA, IBM, Oracle and SAP published consensus specifications BPEL4 People and WS-HumanTask, which described how the interaction of processes with people could be implemented in the system and BPEL notations. It is expected that semantics will be added to BPEL in the form of WS-HumanTask and various other additions.

6.4. Providing the process of analysis and design of IP with the capabilities of CASE technologies

The term CASE (Computer Aided Software/System Engineering) is currently used in a very broad sense. The original meaning of the term CASE, limited to issues of automation of the development of software only, has now acquired a new meaning, covering the process of developing complex IS as a whole.

Now the term CASE tools refers to software tools that support the processes of creating and maintaining IS, including analysis and formulation of requirements, design of application software (applications) and databases, code generation, testing, documentation, quality assurance, configuration management and project management, as well as other processes. Thus, modern CASE tools, together with system software and technical support, form a complete IS development environment.

The emergence of CASE technology and CASE tools was preceded by research in the field of programming methodology. Programming has acquired the features of a systems approach with the development and implementation of high-level languages, methods of structured and modular programming, visual modeling and design tools based on the UML (Unified Modeling Language), tools for their support, formal and informal languages for describing system requirements and specifications, etc. d. In addition, the emergence of CASE technology was facilitated by such factors as:

training analysts and programmers receptive to the concepts of modular and structured programming;
widespread adoption and constant growth in computer performance, which made it possible to use efficient graphics tools and automate most design stages;
the introduction of network technology, which made it possible to combine the efforts of individual performers into a single design process through the use of a shared database containing the necessary information about the project.

CASE technology is an IS design methodology, as well as a set of tools that allow you to visually model a subject area, analyze this model at all stages of IS development and maintenance, and develop applications in accordance with the information needs of users. Most existing CASE tools are based on methodologies of structural (mostly) or object-oriented analysis and design, using specifications in the form of diagrams or texts to describe external requirements, connections between system models, system behavior dynamics and software architecture [Vendrov A. M. . , http://www.citforum.ru/database/case/index.shtml].

CASE tools allow you to create not only a product that is practically ready for use, but also ensure the “correct” process of its development. The main goal of the technology is to separate software design from its coding, assembly, testing and to “hide” as much as possible from future users all the details of software development and operation. At the same time, the designer’s work efficiency is significantly increased: development time is reduced, the number of software errors is reduced, and software modules can be used in future developments.

Most CASE tools are based on the methodology/method/notation/structure/tool paradigm.

The methodology sets guidelines for evaluating and selecting a software development project, stages and sequence of work, and rules for applying certain methods.

Method - a systematic procedure or technology for generating descriptions of software components (for example, descriptions of flows and data structures).

Notations are intended to describe the system as a whole, its elements: graphs, diagrams, tables, block diagrams, algorithms, formal languages and programming languages.

Structures are a means for implementing structural analysis and constructing the structure of a specific system.

Tools - technological and software tools to support and enhance methods.

CASE technologies have the following main advantages, which allow them to be widely used in the development of information systems:

accelerate the process of collective design and development;
allow you to create a prototype of an ordered system with specified properties in a short time;
free the developer from routine work, leaving time for creativity;
ensure the efficiency and quality of developed software by automating control of the entire development process;
support the maintenance and development of the system at a high level.

It should be noted that, despite all the potential capabilities of CASE tools, there are many examples of their unsuccessful implementation, as a result of which CASE tools become “shelf” software.

In this regard, the following must be taken into account:

CASE-remedies do not necessarily give an immediate effect; it can only be obtained after some time;
the real costs of implementing CASE tools usually far exceed the costs of purchasing them;
CASE tools provide opportunities for significant benefits only after successful implementation, effective user training, and regular use.

You can also list the following factors that make it difficult to determine the possible effect of using CASE tools:

a wide variety of quality and capabilities of CASE tools;
relatively short time of using CASE tools in various organizations and lack of experience in their use;
wide variety in implementation practices of different organizations;
lack of detailed metrics and data for already completed and ongoing projects;
wide range of subject areas of projects;
varying degrees of integration of CASE tools in different projects.

Some analysts believe that the real benefits of using some types of CASE tools can only be realized after one or two years of experience. Others believe that the impact may actually occur during the operational phase of the IS life cycle, when technological improvements can lead to lower operating costs.

Listed below are the main types and sequence of work recommended when constructing logical models of a subject area within the framework of the CASE technology for analyzing an enterprise management system.

Conducting a functional and information survey of the management system (administrative and managerial activities) of the enterprise (Fig. 6.1.2):
- determination of the organizational structure of the enterprise;
- determination of the functional structure of the enterprise;
- determination of the list of target functions of structural elements (divisions and officials);
- determining the scope and order of inspection of the structural elements of the control system in accordance with the formulated target functions;
- inspection of the activities of the selected structural elements;
- construction of an FD diagram of a control system indicating structural elements and functions, the implementation of which will be modeled at the DFD level.
Development of models of activity of structural elements and the management system as a whole:
- identifying a variety of external objects that have a significant impact on the activity of a structural element;
- specification of input and output information flows;
- identification of the main processes that determine the activity of the structural element and ensure the implementation of its target functions;
- specification of information flows between the main processes of activity, clarification of connections between processes and external objects;
- assessment of volumes, intensity and other necessary characteristics of information flows;
- development of a hierarchy of data flow diagrams that form a functional model of the activity of a structural element;
- combining DFD models of structural elements into a single model of an enterprise management system.
Development of information models of structural elements and a model of the information space of the control system:
- defining model entities and their attributes;
- conducting attribute analysis and optimization of entities;
- identifying relationships between entities and defining types of relationships;
- analysis and optimization of the information model;
- combining information models into a single model of the information space.
Development of proposals for automation of the enterprise management system:
- determining the boundaries of automation - compiling a list of automated structural elements, dividing the processes of core activities into automatic, automated and manual;
- compiling a list of subsystems and logical workstations (automated workstations), determining ways of their interaction;
- development of proposals for the order of design and implementation of subsystems and individual logical workstations included in the IS;
- development of requirements for basic technical support of information systems;
- development of requirements for basic IS software.

A logical model that reflects the activities of the enterprise management system and the information space in which this activity takes place represents a “snapshot” of the state of affairs (functional structure, roles of officials, interaction of departments, accepted technologies for processing management information, automated and non-automated processes, etc. .) at the time of the examination. This model allows you to understand what the enterprise does and how it functions from the standpoint of system analysis, and to formulate proposals for improving the situation.

The development of a logical model of the subject area, its consistent transformation into a model of the target IS, will allow for the integration of promising proposals from management and leading employees of the enterprise, experts and system analysts, and to form a vision of the new, reorganized and automated activity of the enterprise (Fig. 6.12).

Rice. 6.12.

The constructed model is a complete result for the following reasons.

It includes a model of the existing manual technology adopted by the enterprise. A formal analysis of this model allows us to identify bottlenecks in enterprise management and formulate recommendations for its improvement (regardless of whether further development of an automated system is planned or not).
It is independent and separable from specific developers, does not require maintenance and can be painlessly transferred to others. Moreover, if for some reason the enterprise is not ready to implement the project at a given time, the model can be “put on the shelf” until the need for it arises.
It allows for effective training of new employees in specific areas of the enterprise’s activities, since the relevant technologies are contained in the model.
With its help, it is possible to carry out preliminary modeling of promising areas of activity of the enterprise in order to identify new data flows, interacting processes and structural elements.
It ensures the dissemination of accumulated experience at other enterprises and makes it possible to unify the administrative, managerial and financial activities of these enterprises.

The model is not just the implementation of the initial stages of work and the basis for the formation of technical specifications for its subsequent stages. It represents an independent result that is of great practical importance, since it allows the further use of CASE technologies for the actual design and development of IS.

Paradigm Plus - application modeling and object code generation;

Rational Rose - modeling business processes and application components

Rational Suite AnalystStudio - a package for data analysts;

Oracle Designer (part of the Oracle9i Developer Suite) is a highly functional tool for designing software systems and databases, implementing CASE technology and Oracle's own methodology - CDM. Allows the development team to fully carry out the project, starting from business process analysis through modeling to code generation and obtaining a prototype, and subsequently the final product. A complex CASE tool makes sense to use when targeting the Oracle product line.

Rice. 6.15. Composition of the IBM-Rational CASE tool Fig. 6.16).

6.5. Implementation of information systems

The implementation of corporate IP, developed independently or purchased from a supplier, is often accompanied by disruption (redesign) of existing business processes at the enterprise. We have to rebuild them to meet the requirements of the standards and the logic of the system being implemented. Let us note right away that the introduction of information systems solves a number of managerial and technical problems, but gives rise to problems associated with the human factor.

The implementation of an information system, as a rule, greatly facilitates the management of enterprise activities, optimizes internal and external information flows, and eliminates bottlenecks in management. However, after the system has been successfully installed, “tested” in operation and shown to be effective, some employees show reluctance to use the IS in their work. As a result of the reengineering, it becomes clear that some employees largely duplicate the work of others or are not needed at all. In addition, the implementation of CIS is accompanied by mandatory training, but, as Russian experience shows, there are not many people willing to retrain. Breaking old skills and instilling new ones is a long and difficult process!

It must be clearly understood that corporate IP is designed to simplify the management of an organization, improve processes, strengthen control and thereby provide competitive benefits. Only from this point of view can the benefits of its implementation be assessed.

Following this logic, it becomes clear that although corporate IS is intended in general to provide all users with the necessary information, managing the development and implementation of CIS is the prerogative of the company's top management! Do leaders understand this?

Here, too, we have to fight persistent stereotypes. “Why do I need a corporate system if things at the enterprise are already going well?” “Why break something if everything works?” But most often there is no need to break it. At the first stage, you only need to competently and correctly formalize and transfer the identified processes within which the enterprise lives into corporate IS. Such formalization will only sharpen and refine successful marketing and production ideas, optimize the management and control process and allow for targeted changes in the future.

The introduction of a new IS is a complex process, lasting from several months for small IS to several years for the IS of large distributed companies with a wide range of products and a large number of suppliers. The success of a project for the development (acquisition) and implementation of IP largely depends on the readiness of the enterprise to conduct the project, the personal interest and will of management, a realistic program of action, the availability of resources, trained personnel, and the ability to overcome resistance at all levels of the established organization.

By now, a standard set of techniques for introducing information systems has emerged. The basic rule is to complete the required phases sequentially and not skip any of them.

The following factors are critical to implementation:

the presence of clearly defined project goals and IP requirements;
availability of a strategy for the implementation and use of IP;
conducting a pre-project survey of the enterprise and constructing “As is” and “As will be” models;
planning work, resources and monitoring the implementation of the implementation plan;
participation of senior management in the implementation of the system;
carrying out work on IS implementation by systems integration specialists together with enterprise specialists;
regular monitoring of the quality of work performed;
quickly obtaining positive results at least in part of the implemented IS modules or during its trial operation.

Before starting to develop an implementation project, you must:

formalize the goals of the IS implementation project as much as possible;
estimate the minimum necessary costs and expense items;
set a high priority for the implementation project over other ongoing projects;
give the project manager the maximum possible powers;
carry out mass educational work with the personnel of the enterprise in order to convey to everyone the importance and necessity of the upcoming transformations;
develop organizational measures for the use of new information technologies;
distribute personal responsibility across all stages of implementation and trial operation.

It is also necessary to determine the functional areas of implementation of information system modules:

organizational management;
organizational and administrative support;
business process management;
management, financial planning and accounting;
personnel Management;
document management;
logistics management;
management of relations with clients and the external environment.

In addition to what is listed above, it is necessary to set technological requirements for the implementation of IS:

system platform: implementation and adaptation of a ready-made solution from the manufacturer or custom development in accordance with the customer’s technical specifications.
integrability: data is stored and processed in a single information space - this ensures their completeness, consistency, reliability and reuse; the system may include newly developed and already used technologies and applications.
adaptability: the system is configured in accordance with customer requirements and the characteristics of the customer’s information field.
distributed: the system can function effectively in geographically remote divisions and branches of the enterprise.
scalability: the system can be implemented in the form of a frame containing basic modules and expanded in accordance with the requirements of a changing external and internal environment.

Main phases of information system implementation

Phase "Preliminary work on the preparation of the IS implementation project." During the pre-project survey of the enterprise (Fig. 6.1.4), detailed information is collected about the structural structure of the organization, functional relationships, management system, main business processes, flows within the enterprise (Control Flow, Doc Flow, Data Flow, Work Flow, Cash Flow), necessary for building appropriate models and selecting objects for automation. The timing, resources, types and volumes of work, the range and cost of software, hardware and telecommunications, the cost of personnel training, etc. are assessed.

Phase "Project preparation". After completion of the first phase, preliminary planning and formation of project launch procedures are carried out:

formation of project and expert groups;
distribution of powers and responsibilities;
determination of organizational and technical requirements for the implementation process;
clarifying customer specifications and expectations;
training of the implementation group consisting of specialists from the customer enterprise.

For some reason, the last very important point is often missed when drawing up an implementation plan. But the success of the entire project greatly depends on it! After the start of financing, the project is considered to be launched.

Rice. 6.17. Sample contents of the implementation project repository

Phase "Project Implementation". During the main implementation work, the system environment is created, installed and configured, system administration procedures are determined, and basic hardware and software systems and applications are installed. The system configures the organizational, staffing and organizational-functional structures of the enterprise using such organizational units as a branch, department, division, work group, etc.

Installation, configuration and setup of network and telecommunications tools are carried out, data is transferred from previous local systems and interfaces are formed with legacy and external systems. At the same time, all created models, plans, working software products, documentation are placed in the end-to-end repository of the implementation project (Fig. 6.17

Topic 1. Concept of information. General characteristics of the processes of collecting, transmitting, processing and storing information.

Information is information about certain objects, phenomena or processes in the environment. Any form of human activity is associated with the transmission and processing of information. It is necessary for proper management of the surrounding reality, achieving set goals and, ultimately, for human existence. Any system: socio-economic, technical, or a system in living nature operates in constant relationship with the external environment - other systems of higher and lower levels. Communication is carried out through information that conveys both control commands and information necessary for making the right decisions. The concept of information as the most important element of a system, covering all aspects of its life, can be considered universal, applicable to any systems.

There is no single scientific opinion on the quantitative meaning of the concept “information”. Different scientific directions give different definitions based on the objects and phenomena that they study. Some of them believe that information can be expressed quantitatively, giving definitions of the quantity and volume of information (measures of information), others are limited to qualitative interpretations.

The syntactic measure of information is used to quantitatively express impersonal information that does not express a semantic relationship to objects.

The semantic (notional) amount of information is measured by a thesaurus measure. It expresses the ability of the observer (user) to receive an incoming message.

Pragmatic measure of information. Creating a piece of information happens for a reason, and receiving information can lead to some result. A quantitative measure of information in this case may be the degree of response of the system to this information.

This measure determines the usefulness of information (value) for the user to achieve his goal. It is also relative, determined by the peculiarities of using information in a particular system. It is advisable to measure the value of information in the same units (or close to them) in which the goal is measured.

Information processes (collection, processing and transmission of information) have always played an important role in science, technology and social life. In the course of human evolution, there has been a steady tendency towards automation of these processes, although their internal content has essentially remained unchanged.

Collection of information is the activity of a subject during which he receives information about an object of interest to him. Information can be collected either by humans or using technical means and systems - hardware. For example, a user can obtain information about the movement of trains or planes himself by studying the schedule, or from another person directly, or through some documents drawn up by this person, or using technical means (automated help, telephone, etc.) . The task of collecting information cannot be solved in isolation from other tasks, in particular, the task of information exchange (transmission).

Information exchange is a process during which the source of information transmits it and the recipient receives it. If errors are detected in the transmitted messages, then retransmission of this information is organized. As a result of the exchange of information between the source and the recipient, a kind of “information balance” is established, in which, ideally, the recipient will have the same information as the source.

Information is exchanged using signals, which are its material carrier. Sources of information can be any objects in the real world that have certain properties and abilities. If an object belongs to inanimate nature, then it produces signals that directly reflect its properties. If the source object is a person, then the signals produced by him can not only directly reflect his properties, but also correspond to the signs that a person produces for the purpose of exchanging information.

The recipient can use the received information repeatedly. For this purpose, he must record it on a material medium (magnetic, photo, film, etc.). The process of forming an initial, unsystematized array of information is called information accumulation. The recorded signals may include those that reflect valuable or frequently used information. Some information may not be of particular value at a given time, although it may be required in the future.

Information storage is the process of maintaining original information in a form that ensures the issuance of data at the end user's request in a timely manner.

Information processing is an orderly process of transforming it in accordance with an algorithm for solving a problem.

After solving the information processing problem, the result must be presented to end users in the required form. This operation is implemented while solving the problem of issuing information. Information is usually provided using external computer devices in the form of texts, tables, graphs, etc.

Information technology is a set of methods, production processes and software and hardware, combined into a technological chain that ensures the collection, processing, storage, distribution and display of information in order to reduce the labor intensity of the processes of using an information resource, as well as increase their reliability and efficiency.

Information technologies are characterized by the following basic properties:

The subject (object) of processing (process) is data;

The purpose of the process is to obtain information;

The means for carrying out the process are software, hardware and software-hardware computing systems;

Data processing processes are divided into operations in accordance with a given subject area;

The choice of control actions on processes must be carried out by decision makers;

The criteria for optimizing the process are the timeliness of delivery of information to the user, its reliability, authenticity, and completeness.

Literature:, p. 5-19; , With. 13-19.

Topic 2. Technical means for implementing information processes.

Computer technology is the material basis of information technology, with the help of which the collection, storage, transmission and processing of information is carried out.

It is necessary to distinguish between the concepts of computer architecture and structure. Under computer architecture It is generally accepted to understand a set of general principles for the organization of hardware and software and their main characteristics, which determines the functionality of a computer when solving relevant types of problems.

The architecture of a computing facility must be distinguished from its structure. The structure of a computing tool defines its current composition at a certain level of detail and describes the relationships within the tool. The architecture determines the basic rules for the interaction of the constituent elements of a computing tool, the description of which is carried out to the extent necessary for the formation of the rules for their interaction. It establishes not all connections, but the most necessary ones, which must be known for more competent use of the tool used.

Despite the fact that modern computers do not look at all similar to the first models, the fundamental ideas adopted in them and associated with the concept of an algorithm developed by Alan Turing, as well as the architectural implementation proposed by John von Neumann, have not yet undergone fundamental changes (with the exception of of course, parallel information processing systems).

Any Neumann architecture computer contains the following basic devices:

· arithmetic-logical unit (ALU);

· control device (CU)

· storage device (storage device);

· input/output devices (I/O);

· control panel (PU).

In modern computers, the ALU and control unit are combined into one common device called a central processor.

A modern personal computer contains the following main devices:

External memory devices, most often magnetic disks, on which information and programs are saved even when the power is turned off;

RAM, in which information and the program are located when performing the necessary actions;

The processor, which actually executes commands in the order prescribed by the program;

Input and output devices (such as the keyboard and monitor) through which the computer receives or transmits information and programs from outside.

Externally, modern personal computers usually consist of three parts: a system unit, a keyboard, and a monitor. The system unit is a processing unit; it contains at least the following computer components:

Electronic circuits (processor, RAM, device controllers, etc.);

A power supply unit that converts alternating current electricity into low voltage direct current electricity to be supplied to electronic circuits;

A floppy disk drive (disk drive) used to transfer programs and data between different computers;

A hard magnetic disk drive designed for long-term storage of large amounts of information on a computer.

Peripheral devices include: printers, scanners, speakers, uninterruptible power supplies, modems, removable memory drives, i.e. those devices without which the computer can function independently.

Printers. Printers (print - printing) are automatic printing devices designed for printing the results of computer work (texts, drawings, graphs) onto paper.

Based on the principle of operation, they distinguish between impact matrix, inkjet, laser and other printers.

A scanner is a device that allows you to enter images of texts, drawings, and photographs directly from a paper document into a computer. Desktop scanners are divided into flatbed, roller and projection scanners.

For long-term archival storage of information or for rewriting large amounts of data to another computer, removable memory drives are used.

Removable storage media includes high-capacity memory drives that can be disconnected from the computer and used for their intended purpose. The drives usually have a small weight and volume; they can be easily carried even in a briefcase.

The use of removable drives makes it possible to completely eliminate unauthorized access to confidential data. Information left on the internal hard drive of a computer is always available to an unlimited number of people and can be accidentally damaged.

The following drives are used to accumulate data: floppy disk-based, hard drive type, magneto-optical, streamers, laser, modular, etc.

Literature:, p. 20-39; , With. 100-156.

Related information.