Purchasing Software and the SDLC
Companies that buy rather than develop AIS software still follow the SDLC process, as follows:
• Systems analysis. Companies must conduct an initial investigation, system survey, and feasibility survey. They must also determine AIS requirements.
• Conceptual system design. An important part of conceptual design is a make-or-buy decision must be made.
• Physical design. If software is purchased, some of the physical design phase, such as designing and coding the program, can be omitted. However, it may necessary to modify the purchased software to better meet company needs. Even when software is purchased, companies often design output, input, files, and control procedures.
• Implementation and conversion. Companies must plan implementation and conversion activities, select and train personnel, install and test the hardware and software, document procedures, and convert from the old to the new AIS. They do not, however, develop and test software modules or document the computer program itself.
• Operation and maintenance. The AIS is operated like any other software, and the vendor usually maintains the software.
Selecting a Vendor
Decisions to make or purchase software can be made independently of the decision to acquire hardware, service, maintenance, and other AIS resources. Likewise, these resources can be purchased independently of the software, although the hardware and vendor decisions may depend on the software decision.
Vendors can be found by looking in the phone book, obtaining referrals, scanning computer or trade magazines, attending conferences, or using search organizations. Some vendors flourish for a while and then go out of business. Additionally, many companies offer computer services but have little experience or capital. When vendors go out of business, they often leave the companies that use their products high and dry. As a result, it is important to be selective when choosing a vendor.