Preliminary analysis: Discover the organization’s objectives and the nature and scope of the problem under study. Propose alternative solutions: After digging into the organization’s objectives and specific problems, several solutions may have been discovered. However, alternate proposals may still come from interviewing employees, clients, suppliers, and/or consultants. Insight may also be gained by researching what competitors are doing.
Cost benefit analysis: Analyze and describe the costs and benefits of implementing the proposed changes. In the end, the ultimate decision on whether to leave the system as is, improve it, or develop a new system will be guided by this and the rest of the preliminary analysis data.

Development: The real code is written here.
Integration and testing: All the pieces are brought together into a special testing environment, then checked for errors, bugs, and interoperability.
Acceptance, installation, deployment: This is the final stage of initial development, where the software is put into production and runs actual business.
Maintenance: During the maintenance stage of the SDLC, the system is assessed/evaluated to ensure it does not become obsolete. This is also where changes are made to initial software.