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School of Computer Science & Engineering
University of New South Wales
 Advanced Operating Systems 
 COMP9242 2002/S2 

Address Spaces

Address spaces are recursively constructed from mappings into other address spaces:

• A ``magic'' initial address space maps physical memory one-on-one;
• each address space (pager) can map portions of its own address space into another (cooperating) address space.

This is done with the help of three mapping primitives

Map:

map a page from sender's to receiver's AS
caller retains page

Grant:

map a page from sender's to receiver's AS
page is removed from caller

Flush:

undoes a Map (removes page from receiver's address space)