CASE STUDY: PETRIE ELECTRONICS

STRUCTURING SYSTEMS REQUIREMENTS: PROCESS MODELING

Structuring Systems Requirements: Process Modeling Jim and Sanjay chatted in Jims office while they waited for Sally to arrive. Good work on researching those alternatives, Jim said. Thanks, replied Sanjay. There are a lot of alternatives out there. I think we found the best three, considering what we are able to pay. Just then Sally walked in. Sorry Im late. Things are getting really busy in marketing right now. Ive been putting out fires all morning. Sally sat down at the table across from Sally sat down at the table across from Jim.

I understand, Jim said. But to stay on schedule, we need to start focusing on the specifics of what we want our system to do. Remember when you wanted more details on what the system would do? Well, now we start to spend some serious energy on getting that done.

Awesome, replied Sally, as she pulled a Red Bull out of her oversized bag and popped it open.

Ive got a list here of four core functions the system must perform, said Sanjay, pulling copies of a list from a folder on the table (PE Table 6-1). Lets look at these.

After reviewing the list Sanjay had given them, Jim said, Nice job, Sanjay. But we need to put this in graphical format, so that everyone can see what the inputs and outputs are for each function and how they are related to each other. We also need to see how the new system fits in with our existing data sources. We need

Some data-flow diagrams, Sanjay interrupted. Exactly, said Jim.

They are already done, replied Sanjay, handing diagrams to both Jim and Sally. Ive already created a first draft of the context diagram [PE Figure 6-1] and a level-1 diagram [PE Figure 6-2]. You can see how Ive defined the boundaries of our system, and Ive included our existing product and marketing databases. What can I say? Jim said. Again, a nice job on your part. These diagrams are both good places for us to start. Lets get copies of all of this to the team. Ill be right back, Sally said, standing up. I need to get some coffee.

Case Questions

1. Are the DFDs in PE Figures 6-1 and 6-2 balanced? Show that they are, or are not. If they are not balanced, how can they be fixed?
2. Decompose each of the core processes in PE Figure 6-2 and draw a new DFD for each core process.

3.. Why is it important for the team to create DFDs if they are not going to write the actual system code themselves?

REFERENCE BOOK TO THE QUESTION

ESSENTIALS OF SYSTEMS ANALYSIS AND DESGN (6^TH EDITION)

AUTHORS: JOSEPH S. VALACICH, JOEY F. GEOGRGE, JEFFREY A. HOFFER

CHAPTER SIX, PAGE 191 193