Development & Implementation of Software
This lecture will examine several additional areas related the development and implementation of software. First of all many organizations must compare and evaluate the costs and schedule tradeoff of building an information system in house versus buying a vendor software product versus having a custom system built by contractors.
A number of organizations continue to build their own software today but usually do not spend resources developing standard administrative applications such as payroll, human resources, or accounting which can be purchased as Commercial off the Shelf software. Commercial off the shelf software is often referred to as COTS. In many instances, where an organization has a development staff, those resources will often be put to use developing information systems that can increase the profitability of the organization as well as those that which might provide a competitive advantage.
The most popular reason behind purchasing and using the COTS alternative today is that the software can be acquired and installed within a reasonably short time frame with the functionality required. As previously stated, it is often more cost effective to acquire and install an administrative information system from a vendor if it will not provide any competitive advantage to the organization.
Another reason for acquiring a COTS information system is the ability to acquire an information system that has been built by industry "experts" with expertise that doesn't exist within the organization.
The need to customize software is usually the result of unique requirements identified by the end user management. The context in which customization is being discussed here is not the same as in-house development. This context for customization is related to the use of a COTS purchased information system. A valid situation for a customization can occur when the basic functions, data capture, and information output of the COTS acquired software appears to be good but not quite adequate fit to the requirements needed by the organization. Although customization does take place, a critical element is the access to the source code for the application. While it might be possible to acquire the source code from the software vendor, it might also be cost prohibitive to do so. Additionally, the modification to the COTS source code would likely eliminate vendor support of the product.
The approach most often taken when using COTS is to develop customized interfaces from existing information systems to pass data into the COTS application as well as developing customized reports to satisfy management requirements. This approach is often a successful implementation strategy into today's information technology environment. Another aspect of customization in today's COTS environment is products that can be customized or parameter driven to meet the needs of many organizations. Leading
COTS packages such as SAP, BAAN, Lawson, and Oracle can be customized to meet
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the needs of different organizations in different industries. This form of customization does not modify the source code but utilizes organization data that is populated in the database along with operational parameters that will allow the software to operate as if it has been uniquely developed for the organization.
When implementing an information system, there are various testing activities that must take place. The basic premise of testing is to make sure the software is working properly before releasing the software into a production environment. There are testing procedures that can be used to ensure the validity of the software.
Unit testing is the typically the responsibility of the programmer. The programmer will usually create test data to make sure the program can process the test data without failure. One mistake occasionally made by the programmer is to…