I was wondering
- Generally, does specification mean interface, regardless the implementation beneath the interface?
Only systems fully compliant with and certified according to the Single UNIX Specification are qualified to use the trademark "Unix"; others might be called "Unix system-like" or "Unix-like" (though the Open Group disapproves of this term).
Suppose not considering the certification, how shall one know if an OS is Unix-like or Unix, and what it means to be compliant with the specification?
For an OS that can be called "Unix", must its implementation also satisfy some requirements besides meeting the specification?