* Functionality: These are the bare minimum features or capabilities needed for the system or product to work at all. Without these, the system is unusable or fails to meet its core purpose. Examples include:
* A web application needs a working login system.
* A car needs an engine.
* Software must be able to load and execute basic commands.
* Safety and Compliance: These are requirements mandated by law, regulations, or safety standards to prevent harm or ensure legality. Examples include:
* Medical devices must meet FDA standards.
* Software must comply with data privacy regulations like GDPR.
* Buildings must meet fire codes.
* Performance: These specify the lowest acceptable level of performance the system must achieve to be considered functional. Going below these levels renders the system unusable or significantly impacts its value. Examples include:
* Minimum processing speed for a computer game.
* Maximum response time for a web server.
* Minimum data throughput for a network connection.
* Usability: While often a spectrum, absolute minimums in usability may focus on accessibility or preventing catastrophic user errors. Examples include:
* A website must be accessible to users with screen readers (ADA compliance).
* Software must prevent users from accidentally deleting critical data without confirmation.
* Security: These define the basic level of protection needed to safeguard data and prevent unauthorized access. Examples include:
* Password requirements to prevent weak passwords.
* Basic encryption to protect sensitive data at rest and in transit.
* Resource Constraints: These are dictated by limitations in budget, time, or available resources. These constraints often influence the minimum acceptable level in other areas like functionality or performance. Examples include:
* Maximum memory usage for a software application.
* The maximum number of users a system can support.
Establishing absolute minimums often involves a careful balancing act between these different criteria. Prioritizing safety and compliance usually comes first, followed by core functionality. Performance, usability, security, and resource constraints then shape the final minimum acceptable standards. The process typically involves trade-off analyses and risk assessments.