Wed, 28 September 2016, 22:18

A student writes:

> Hello Dr. Patt,
> My name is *****, a student in your Computer Architecture class. Today
> when you discussed the Page Directory and you said each entry was PTE (Page
> Table Entry), it was not quite correct. Each entry of the Page Directory
> should be Page Directory Entry, according to the Intel's manual that I
> attached in this email. I am aware that you may not care about naming of
> these things but I hope it does not cause confusion to some student.
> --
> Best,
> <<name withheld to protect the student who is absolutely correct>>

The student is of course absolutely correct, (a) the entry is called a Page
Directory Entry, (b) I am far less interested in the actual names of these
things and far more interested in you understanding the concepts, and (c)
I do not want any student to be unnecessarily confused.  Ergo, I am forwarding
his correction to all of you, including the figure he sent which is much
prettier than the one I drew in class.

Incidentally, since I have your attention, do you know why there are 32 bits
coming out of CR3 but only 20 bits coming out of the PDE and the PTE?

Yale Patt