ASE 12.5.1

From the Sybase online manual (A):

'Note that the logical page size is not the same as the memory
allocation page size. Memory allocation page size is always 2K,
regardless of logical page size, which can be 2, 4, 8, or 16K.'

Again manual says (B):

'
Note that the logical page size is not the same as the memory
allocation page size. This is the unit in which disk space is
allocated, and Adaptive Server allocated this space in 2K pages
'

Again (C):

'
Adaptive Server allocates buffer pools in units of logical pages.
'

I am comfused. To me, logical page size is used when disk space is
allocated. But if so, how can I understand part C above?

Could anyone give me clear definitions for these two pages? And what's
the relationship between 'memory allocation page size' and the way
Sybase allocate data cache pool?

Thanks a lot!