software requirements 2 karl wiegers pdf free download

Nonfunctional requirements aren’t directly implemented in software or hardware. When people talk about nonfunctional requirements, they’re usually referring to quality attributes. The terms design for excellence and DfX refer to quality attributes as well, where X is a property of interest that designers strive to optimize. Software project teams must consider a broad set of quality attributes as they explore requirements. Consequently, an essential part of requirements analysis is understanding which quality characteristics are the most important so that designers can address them appropriately.

There are inevitable trade-offs among various aspects of quality-increasing one often causes an unavoidable decrease in another. It’s impossible to get the best of all possible worlds for every aspect of a software system’s capabilities and characteristics. Oh, yes, I almost forgot-this app should be free too.ĭoesn’t that sound like a fabulous app? It sure does! Are my expectations reasonable? Of course not! It should let me import and export any data I need from other sources. I should be able to use the app on any device I want with instantaneous downloads and no timeouts. The user interface should never let me make a mistake. I don’t want to see any “internal server error” or “application is not responding” messages. It should respond instantaneously to my every command and be completely reliable. The app should be completely secure: no one can steal my data or impersonate me. It shouldn’t use much memory or slow down my computer, and it ought to free up all the memory it used when it’s done.

The next software app I use had better not have any bugs in it: no 404 “page not found” errors or help screens that don’t match the form with which I’m working.

Software requirements 2 karl wiegers pdf free download