Application architecture and Process Design:- Applications are designed according using a system development life cycle, which passes through several phases including requirements gathering, design, implementation, testing, and maintenance. We describe the application design process by designing an information system for Riordan Manufacturing, Inc. , an industry in the field of plastic injection moulding. The first step of design is to identify the processes and the entities. Processes represent the operations performed by the system. Entities represent all the information sources of the system. We represent the entities and the processes in the data flow diagrams, DFD. While designing the DFD’s we increase the level of detail with each level. At each level the process divides into sub-processes until indivisible sub-processes are reached. Here is an example. Data Flow Diagram 0: Here we represent the information system at Riordon Manufacturing Inc. The information system comprises of :
- Employees
- Clients
- Manager Employees
Employees are the people working for Riordan Inc. Their job is to make innovative plastic designs of international acclaim, help in the production of the finished plastic products from these designs,etc. They include the Chemical Engineers, Labour, etc. Clients The Clients or the customers are the people who give orders to purchase the finished products developed in the industry. Manager Manager is also an employee at Riordan Inc. but his job is more important as he has to manage the whole Information System. He has to look into the Sales and the Accounting and also talk with the Clients. He also listens to the problems of the employees and the complaints from the Clients and takes the corrective measures. Visitors Visitors are the group of people who visit the industry’s website to gather information about the company and its products but are not interested in placing the orders right now.
Diagram 0 is divides into the following modules: – Production – Sales – Accounting Production: The production module at Riordan Inc. is linked with the Sales and the Accounting modules. The amount of production is directly linked to the sales, if the sales in a particular financial year are high then the production is stepped up, on the other hand if the sales are low then the production is slowed down. Production module is also directly linked to the Accounting module as the cost of production and the raw materials purchased by the company for the production are directly a part of the Accounting process. Sales: The sales module is linked with the Clients and the Manager. The Clients place the order for the products which leads to sales and the Manager manages the whole sales process. Accounting:
The accounting process is linked to the Sales and the Production modules as they directly affect the Accounting at Riordon Inc. Employees and the Clients have also been linked to the module as employees take their salary from the company bank accounts and the Clients deposit the cheques in the bank accounts. In the DFD it has been shown that the employee controls the production system. The production system sends the details to the stock (inventory database). The sales module takes the updates from the stock inventory to check whether the products being ordered by the customer are actually available or not.
If they are not then the product request is rejected otherwise accepted. The accounting process subtracts the salary of the employees from the accounts of the company. It also adds the earnings from the Clients and other sources like the government funds,etc. to the accounts database. Manager finalises the sales decisions and supervises the accounting process. [pic] Data Flow Diagram 2 Each module has been divided into the various processes that handle it. Sales Module has the following processes: PlaceOrders Billing Update_Inventory Update_Software
Accounting Module has been divided into the following: Subtrac Salary Employees Subtract Production Costs Add Earnings Client – Update_Software Here the DFD 2 shows that once the Client places a demand for a particular product, the Order Input process sends the update to the manager. Manager runs the process stock_check to see whether the product is available in the inventory of the company or not. The output given by the Stock Check process is sent to the Order Input process which takes the appropriate action depending upon the output. Billing is handled by the Billing and payment process.
The Client pays the bills by either giving their Credit card numbers or the Demand Draft Numbers (with the demand drafts being sent to the company headquarters). All this is handled by the billing process. Once we draw the data flow diagrams, we concentrate on data design, in data design we draw ER diagrams, consisting of all entities and their attributes. The diagram also shows the relationships between the entities. It also explains the multiplicity between various entities. Once an ER-diagram is designed it can be directly converted into database tables.
Networking model represents the interconnection and details of all the hardware’s present in the system, we first note down all the hardware required and then represent it, by describing or by diagram. Here is a description of network model for our problem. The networking model AT Riondan Inc. is a client/server design. Each locality dedicates hardware (servers) for handling the application requests from the workstations. All locations support more than 10 users. The current network consists of hubs, Cat3 cabling, Windows 98 workstations and NT Servers.
All facilities are employing firewalls on the network. Good Bandwidth enables efficient and fast data transfer between different plants. The local area networks (LAN) mirror one another and are standardized within the WAN. The networks follow the Bus and Ring topology principals with two WAN connections. Each network patterned on a 100 base T Ethernet backbone with an edge router for data transmission to and from the other locations and external sources on a full T1 line. The number of users supported in each location is between 35 and 50 users, per site.
In addition, each location is running the following servers: basic Windows NT network servers, UNIX based servers, and NAS file storage servers. Each location contains a satellite connection that serves as a back up for these locations in the event that the primary T1 line is unavailable. Each network is daisy-chained to comprise the backbone. The following protocols are being used at Riondan Inc. TCP/IP (Transmission Control Protocol/ Internet Protocol) LAN Routing and transport protocol, which holds the entire network together. SNMP (Simple Network Management Protocol) Network management protocol for managing the network infrastructure.
- FTP(File Transfer Protocol) File transfer protocol for WAN/LAN wide file transfers.
- DNS (Domain Name System) Domain naming system for network name resolution.
REFERENCES
- Bennett,Simon (2006) Object-Oriented Systems Analysis and Design, 2nd edition, papaerback.
- Orfali, Robert(1996) The Essential Distributed Objects Survival Guide , 2nd edition John Wiley & Sons
- Amyot, Daniel; Williams, Alan W. ( 2005) System Analysis and Modeling, 4th edition, Springer publications.
