 | Derive Current System Dependency Diagram |
| Map Current to Target Dependency Diagrams |
| Summarize Function Dependency Analysis |
In order to continue the functional assessment of the current application, an organization should develop a function dependency diagram of the current system. This diagram graphically depicts the sequence of functions within a system.
A function is dependent on another function when a prior function puts an entity in a state required by that subsequent function. Function dependencies are used in designing new systems and are a good way to formally re-document functional flows for existing systems.
Functions derived from current systems during function hierarchy analysis are now represented in a hierarchy that links existing functions, processes and programs.
Dependency analysis of existing systems, based on previously extracted functions, allows analysts to trace functions throughout a system. This assists in planning both enhancements as well as large scale redevelopment projects. Specific objectives include:
· Define functional dependencies based on how system functions flow in the current system(s)
Optional - Based on availability of top-down dependency diagram(s)
· Assess similarities and differences between current and target function dependency analysis
· Refine target analysis based on current functional dependencies
The entrance criteria for the function dependency analysis task are listed below.
· Completion of environmental analysis task for system being assessed
· Completion of general system architecture assessment, particularly flow analysis of systems entering this task
· Completion of the function hierarchy analysis for systems entering this task
Optional - based on availability of top-down architecture
· Completion of the program/process/function mapping analysis as depicted on functional mapping Form 004
· Completion of current to target mapping in the function hierarchy analysis task for systems being assessed
Optional - based on availability:
· Populated LTM model as completed in entrance criteria tasks
The personnel and skill requirements necessary to meet the function dependency analysis task objectives are identified below.
· Redevelopment Expert
- Knowledge of existing system analysis and dependency derivation process
- Rudimentary repository access skills
· Current Systems Expert
- Knowledge of existing system functional flows
- Knowledge of existing program/function flow
· Target System Functional Analyst
- Knowledge of target functional requirements
· Function Modeling Expert
- Expert at building top-down and bottom-up function dependency diagrams
The system components and related inputs required to initiate and complete the function dependency analysis task are listed below.
· JCL, Proc, Step to Executable Program cross reference analysis from environmental analysis task
· Current program/process/function mapping as entered on Form 004
· Function hierarchy diagram for the current system
· High-level system data flow diagrams from general system architecture assessment
· System/sub-system interface map (DFD) from general system architecture assessment
Optional - based on redevelopment objectives
· Target application function dependency diagrams
· Current to target function mapping Form 004 for each system being assessed
Optional - where available based on prior assessment tasks.
· Legacy transition meta-model (LTM) populated with all system components and relationships based on use in prior tasks - supports current system step sequencing analysis
Technologies supporting the function dependency analysis task include I-CASE modeling, spreadsheet, project management, open systems repository word processing tools. These tools are used to represent information as required by this task.
I-CASE Modeling Tools
I-CASE planning, and optionally analysis, tools capable of defining function and process hierarchies, support this task. The use of an integrated tool set supports the mapping of entities to functions during matrix development in the final task of the functional assessment.
Open systems repository>
A repository provides an important, yet optional, capability to link business areas, systems and components using the legacy transition meta-model. In this task, the repository is used to track job execution sequencing.
Spreadsheet
This tool is used to record metric results for this task.
Word processor
This is required to record analysis results.
The function dependency analysis task is comprised of the following task steps:
Derive Current System Dependency Diagram Map Current to Target Dependency Diagrams Summarize Function Dependency Analysis