This preview shows page 1. Sign up to view the full content.
Unformatted text preview: tice that no data is actually transferred between disk and memory. For this reason, pages in areas that are mapped to anonymous ﬁles are sometimes called demand-zero pages. 10.8. MEMORY MAPPING 517 In either case, once a virtual page is initialized, it is swapped back and forth between a special swap ﬁle maintained by the kernel. The swap ﬁle is also known as the swap space or the swap area. An important point to realize is that at any point in time, the swap space bounds the total amount of virtual pages that can be allocated by the currently running processes. 10.8.1 Shared Objects Revisited
The idea of memory mapping resulted from a clever insight that if the virtual memory system could be integrated into the conventional ﬁle system, then it could provide a simple and efﬁcient way to load programs and data into memory. As we have seen, the process abstraction promises to provide each process with its own private virtual address space that is protected from errant writes or reads by other processes. However, ma...
View Full Document
This note was uploaded on 09/02/2010 for the course ELECTRICAL 360 taught by Professor Schultz during the Spring '10 term at BYU.
- Spring '10
- The American