You be a bit upset by that?
This is an exclusive or.
The or in this case means one or the other, or both and
then there's the problem of people saying and when they mean or.
The moral of this story is we need to be very careful of the language we use when
developing these statements.
So let's distinguish them a little bit.
User requirements are exactly what the user wants the solution to do in
the user’s language.
Users do not want to log in though, we want them to.
They want the system to be secured to only allow them to say,
post to Facebook on their behalf.
Logging in is the systems specification.
The required action of the system solution were developing.
System spec is the usually more precise or
constraining statement of how the system will meet the user requirements.
This is still with the solution we'll do not how, but
it's how the system will meet the requirement.
Software design then takes this requirement specification and details that
how, which modules be constructed will it be oriented toward design and development.
How do we make it happen?
This still may not be clear, so let’s take a quick example.
Take this user requirement.
We want to make a boat and sell to the general public.
We talked to some users to find out what they want, so
that we can build what they want so we can make money.
We can tell when a user can put our boat on a rack by themselves,
but how do we constrain and specify our solution to make sure that happens?
Because the generic statement, one person must be able to load the boat on a car
rack doesn't really give our design team anything to go on.
So we specify the solution in such a way that our specification means that we
have met the requirement here.
Now, we have at least a partial list of things we must meet.
And if we meet these things, we have met the user requirement or
at least we think we have.
This is another area of potential mistake.
Making assumptions about whether these specifications will translate about having
met the requirement.
So you need to take care that these and
only these are sufficient to meet the requirement.
So we assume that if the boat's lighter than 100 pounds that it has handles,
that one person can load it onto the car rack.