Quality requirements of an IS

Information System: a set of interrelated components (people, hardware, software, data, networks, procedures) that collect, process, store and distribute information to support decision making, coordination and control in an organization.

Components of an information system

1. Hardware - computers, servers, storage, input/output devices.
2. Software - system software (OS, DBMS) and application software.
3. Data - raw facts that are stored and processed into information.
4. Network / Telecommunication - links (LAN, WAN, Internet) for sharing data and resources.
5. People - users, analysts, programmers, administrators and managers who run and use the system.
6. Procedures - rules, manuals and policies that describe how the system is used and controlled.

 Input -> Processing -> Output
            |   ^
         Storage  Feedback/Control

Quality requirements of an information system

• Accuracy - output is free from errors and reflects reality.
• Timeliness - information is available when needed.
• Relevance - information suits the decision at hand.
• Completeness - all needed information is present.
• Reliability and availability - system works consistently with little downtime.
• Security - protected against unauthorized access and loss; confidentiality and integrity are kept.
• Usability - easy to learn and use.
• Flexibility and scalability - can adapt to changing needs and growing load.
• Efficiency and cost-effectiveness - uses resources well.
• Maintainability and integration - easy to fix, upgrade and connect with other systems.