Overview on External and Internal Design

External Design

In this phase, the full details of the system functions, screen and report formats, external interfaces, security and audit controls, operational procedures, recovery and contingency procedures and reponse times are defined.

Internal Design

This phase is concerned with the internal details of the system such as databases/files, records and programs. For each program it defines the functions it performs, the files accessed and the input and/or outputs processed.

Overview of SDLC

System Development Life Cycle (SDLC) sets out the steps to be performed when developing systems, the work to be done in each step and the deliverables to be produced. It applies to all types of system development projects. By following SDLC, it ensures planning the project at the beginning and monitoring it along the way so that the schedule is met and the final system meets the requirements.

SDLC comprises a number of consecutive phases:

1. Initial Request
2. Feasibility Study
3. External Design
4. Internal Design
5. Programming
6. System Test
7. Acceptance Test
8. Implementation
9. Post Implementation