According to the book Microsoft Sql server 2012, Chapter 13 (Transactions and concurrency):
If an exclusive page lock is held in one page of a table, another process can not get even a shared table lock for that table. This hierarchy is protected using intent locks. A process acquiring an exclusive page lock, update page lock or intent exclusive page lock first acquires an intent exclusive lock on that table. This intent exclusive table lock prevents another process from acquiring the shared table lock on that table.
And according to another paragraph of this book:
... lock compatibility is an issue only when the locks affect the same object. For example two or more process can hold exclusive page locks simultaneously, as long as the locks are on different pages.
I think these two paragraphs are in contradiction with each other, because in the first one it is said that if there is an exclusive lock on a page a table, other type of locks can't be granted on the whole table to other processes In the second paragraph it is said that it can be granted if it is on a different page.
Which one is true?