System Hierarchy and Subsystem Classification Principles

System Hierarchy and Subsystem Breakdown

The breakdown begins by subdividing the total target system into a series of simpler subgoals. Each subsystem is designed to have its own specific objectives. If the objectives of this initial group remain complex, they should be further subdivided into smaller goals. This process continues until reaching the so-called Black Boxes, where the only critical information required is the inputs and outputs produced.

Every system is potentially:

• A subsystem of a larger system.
• A component of a supra-system or meta-system.

System Interactions

All subsystems are interconnected through interactions, categorized into four basic types:

• Series (Chain): The output of a predecessor subsystem becomes the input of the successor subsystem.
• Parallel: The output of a predecessor subsystem feeds into two or more successor subsystems, or the outputs of multiple ancestor subsystems feed into a single successor.
• Immediate (Direct) Feedback: The output of a predecessor subsystem feeds into the successor, and the output of the successor is fed back as the entry for the predecessor.
• Mediate (Indirect) Feedback: Involves at least three subsystems where the output of the first is the input of the second, the output of the second is the input of the third, and the output of the third is fed back into the first.

Ackoff's Laws of Systems

Three fundamental laws apply to all systems:

1. The behavior of a system element affects the behavior of the entire system.
2. The behavior of an element that affects the system depends on the behavior of at least one other element within that system.
3. Each subsystem (set of elements) possesses the two properties mentioned above.

System Classification

Systems are classified based on computer usage:

• Non-Computerized Systems
• Computerized Systems

Types of Computerized Systems

• Batch Systems
• Online Systems
• Real-Time Systems
• Decision Support Systems
• Strategic Planning Systems
• Knowledge-Based (Expert) Systems

Characteristics of Batch Systems

Information is entered in batches, processed, and retrieved sequentially, recording data one item after another.

Characteristics of Online Systems

• Data is entered remotely via keyboard terminals, barcode readers, or other input devices.
• Data is organized in files and databases, allowing for direct retrieval, reading, or modification from workstations.
• The system interfaces directly with the user.