Unit 3
Terms 1 & 2 (20 weeks)
Focuses on developing computer-based systems and producing spreadsheet and database solutions. Students study systems analysis and development, then apply managing data skills.
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Systems Analysis
Systems Analysis and Development
Project Management
System Development Life Cycle (SDLC)
Methodologies include prototyping and the SDLC. The SDLC is a structured approach to system development.
The cycle returns from Evaluation & Maintenance back to Preliminary Analysis
Context Diagrams (Yourdon/DeMarco)
A context diagram is a single-process view of a system with external entities and data flows.
[Customer] ---- order ----> (System) ---- receipt ----> [Customer] [Supplier] ---- delivery -> (System) ---- invoice ---> [Supplier]
Common Mistake: Context diagrams should only have ONE process (the system). Multiple processes means it's a DFD, not a context diagram.
Hardware and Software
Hardware
Physical components: input, output, processing, storage
Software
Operating systems, utilities, and applications
Storage Units
| Unit | Equivalent |
|---|---|
| 1 byte | 8 bits |
| 1 kilobyte (KB) | 1024 bytes |
| 1 megabyte (MB) | 1024 KB |
| 1 gigabyte (GB) | 1024 MB |
| 1 terabyte (TB) | 1024 GB |
CPU Components and Fetch-Execute Cycle
Fetch-Execute Cycle
Managing Data
Spreadsheet Fundamentals
Key terms: cell, formula, function, label, worksheet, lookup table.
Common Mistake: Confusing formulas (calculations like =B2*C2) with functions (built-in operations like =SUM()).
Data Hierarchy
Database Concepts
Data Integrity
Accuracy and consistency of data
Data Redundancy
Unnecessary duplication of data
Common Mistake: Mixing up data integrity (correctness) with data redundancy (duplication).