SLC Exam Preparation
Class 12 Computer Science Notes
A System is a collection or arrangement of entities or things that work together to achieve one or more common goals.
It can also be defined as, a set of components linked together according to a plan to achieve a specific objective.
In a typical system one or more inputs are changed into a desired output. Systems may be made up of other smaller systems, which are called as Subsystems. Subsystems in turn are made up of other subsystems.
For example, a Computer System is made up of number of subsystems, which are input subsystem, storage subsystem, processing subsystem and output subsystem.
Information System is as a system, which gathers and delivers information to the people in an organization. The purposes of Information Systems are to process input, maintain files, and produce information and reports about the organization.
An Information System, today, is considered as subsystem of business. An information system is a set of processes and procedures that transform data into information and knowledge.
Information Systems consists of subsystems, including customized hardware and software along with data that’s central to the company or organization’s mission, trained users who know how to use the system to serve customers better, and procedures that outline precisely how to accomplish a task with out error. The five basic interacting components of any information system are;
Capturing / accepting components that enter into the system to be processed. Example: raw data.
Process that series of changes to be done on information, to convert input into output. Example: data processing.
Which produced by the transformation process to their ultimate destination. Example: reports.
TYPES OF INFORMATION SYSTEM
There are different types of Information Systems. They are:
a. Data Processing Systems (DPS)
A DPS process transactions and produce reports. DPS represents the automation of basic, routine processing to support operations. Typical examples of DPS are payroll, inventory, financial accounting etc.
b. Management Information Systems (MIS):
MIS can be defined as information system for providing information to support operations, management, and decision-making. MIS utilize computer, procedures, analysis, planning, control, decision-making, and a database. Users of MIS, normally, use a shared database.
c. Decision Support Systems (DSS):
DSS supports decision makers by providing information on demand. DSS tends to be used in planning, analysing alternatives and search for solutions. DSS is similar to MIS, in that, they both depend on a database as a source of data. DSS differs from MIS in that it emphasises the support of decision making in all of its phases. Though, the actual decision is still in the hands of the decision maker.
d. Expert Systems (ES):
Expert Systems capture the expertise of decision makers in solving problems. ES automates the decision-making process in a specific area, such as medical diagnoses or review of credit history for loan approvals.
System Development Life Cycle (SDLC):
System Development is the creation of new system or modification of old system. Systems development involves number of stages starting from Systems Study to Systems implementation and maintenance. SDLC is an organized way to build an Information System. SDLC, in fact, is a sequence of events carried out by Systems Analysts, Systems Designers, and users to develop and implement an Information System.
The system development life cycle (SDLC) can also be defined as, a framework for developing computer-based information system. In order words, SDLC is the overall process of developing information system through a multi-step process from investigation of initial requirements through analysis, design, implementation and maintenance. These activities are carried out in different phases, which are mentioned below:
1. Problem Definition
2. System Analysis
3. System Design
4. System Development
5. System Testing
6. System Implementation
7. System Evaluation
8. System Support & Maintenance
All these phases, together, are called a life cycle because they cover the entire life of an Information System.
Notes Written by:
Komal Singh: Komal Singh is a Computer Teacher at Janjyoti HSS, Florida , Western Public and Ghatal HSS.