¤ Prepare procedure dependency diagrams:
Prepare a procedure dependency diagram by mapping the elements of the process dependency diagram. When process to procedure mapping is 1:1 for every process, this exercise is trivial. More thought is required, however, whenever the process to procedure mapping is not 1:1.
The procedure dependency diagram is simply a copy of the process dependency diagram, where each:
* Process becomes a procedure
* Information view becomes a data view
* External process becomes an external object
* Process dependency becomes a data flow
» Creates deliverable D4.1.2 Procedure Dependency Diagram.
¤ Define the data views:
Define each data view as a collection of other data views and/or fields, and document this in the information library.
Identify the data views while you construct the procedure dependency diagram.
¤ Determine the data stores:
Before constructing the data flow diagram, define the data stores. The general approach involves defining a data store for each prospective physical file. By defining a data store, you are not committing yourself to using one physical file for that data store. The actual physical files will be determined during the TD phase of design stage.
Each data store is defined in the information library. It is assigned a name, given a brief description, and associated with the record types it contains. In some cases (e.g., transfer files and clerical files) it will also be necessary to define the record types.
Examples of Data Stores
A data store could be:
* An entire database
* A part of a database
* A master file
* A transfer file for interfacing procedures or systems
* A clerical file
» Creates deliverable D4.7.7 Record Types List.
» Creates deliverable D4.1.7 Data Store Description.
¤ Construct data flow diagrams:
Convert the procedure dependency diagrams to data flow diagrams using the Data Flow Diagramming technique.
» Creates deliverable D4.1.6 Data Flow Diagram.
¤ Synthesize to higher-level data flow diagrams:
The data flow diagram that has been drawn at the procedure level is now summarized at the subsystem and system levels.
» Creates deliverable D4.1.6 Data Flow Diagram.
¤ Check diagrams:
The diagrams will be checked formally as part of the Confirmation task, but, at this point, it is sensible to check the consistency of what has been drawn, and the completeness of the documentation.
¤ Design the system controls:
System controls, which are requirements arising out of the system design, are now defined. The controls required by the business auditors that are independent of the design should have already been defined as processes during BAA. These controls should be reviewed again at the end of the "Procedure Design" task.
ð Updates deliverable D4.1.1 Procedure Definition (for System Controls).
¤ Design fallback procedures:
For each procedure, the consequences to the business of a failure of
the computer system must be analyzed. You must decide whether the procedure
can remain unavailable for the maximum expected outage, or whether alternative
procedures must be available. When deciding on the fallback procedures,
consult the output of the procedure design task and the data flow diagram.
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Activity Overview : A4.1
Stage Overview : Design Stage
Overview : Table of Contents