Unfortunately some users are confusing two different issues:
A: name of Kurds and its roots.
B: origins of Kurds (i.e. who were Kurds forefathers.)
its is not completely clear what is origin of the name of Kurd. there are scholars who agree that it has a Sumerian root, used :A: either as a topynom for Kurdish regions or as a name for Hurrians. Some scholars who probably never heard about Sumerians think that it may origin from Corduchi, some others who are too biased say it is an Arabic word, though in Arabic language there is no root for a verb as KRD, for example in Arabic KTB exists and we can derive hundreds of words from this word, yaktubu, katib, maktub etc... but it is not possible with KRD;  this means that the word has a non-Arabic root and therefore it has a pre-Islamic origin.  before Arab invasion few Kurds were adientified as Kurds; but mostly either as Mede, or after name of their tribes. 
B: as for origins of Kurds I think Minorsky is a prominent iranologist. what he says is considered as valid.