Premise: After it has been installed, the DOS, as it is called (once identified, nothing in computerese is ever called by its full name  a Personal Computer becomes a PC; a Disk Operating System becomes a DOS; if it is made by a company called MicroSoft, it is called MS/DOS), performs certain functions, though rarely any that anyone but a computer specialist would want to perform.

Hypothesis: Nothing in computer sense is called by its full name.
Relation: entailment