To implement a system successfully, a large number of inter-related tasks need to be carried out in an appropriate sequence. They describe the required functionality that the final deliverable must have or specific conditions the final deliverable must meet in order to satisfy the objectives of the project.
Functional Requirements Functional requirements describe the characteristics of the final deliverable in ordinary non-technical language. Common problems that arise during implementations include the missing of deadlines, going over budget for the entire project, underestimating hours that staff is devoted to a project, running into unexpected delays or blockages due to an external partner and facing the withdrawal of support from key stakeholders or various unforeseen consequences that could otherwise slow the process down.
Final thoughts Successful project delivery is not a rocket science. But if you are sending emails to stakeholders by yourself, then you are certainly not doing it in the best way, you are spending time on things which are best handled and automated by project management tool.
Similarly, for the computer system example, you might specify values for the generic types of performance constraints: The response time for information is displayed on the screen for the user.
Communication strategy and plan is crucial for greater project visibility and ultimately for project success. Sometimes, this might require an auditor -- either from a third partya vendor, or someone internally -- to be brought in to evaluate every customer-facing business process to diagnose problem areas or inefficiencies that need to be corrected.