Virtual Memory Page Translation Quiz

Study Flashcards Play Quiz

Questions and Answers

In a paging system, what is the main advantage of dividing virtual address space into fixed-size pages and physical memory into fixed-size frames?

ANY virtual page can be stored in any available frame, making finding an appropriately-sized memory gap very easy.

What is the purpose of the table maintained by the OS for each process?

The table maps each virtual page to a physical frame.

In a 32-bit virtual address, how many bits are used to address each byte in an 8-KB page?

13 bits

What is the term for the process of translating a virtual address into a physical address?

Address translation Signup and view all the answers

In a 32-bit virtual address, what is the purpose of the remaining 19 bits after the 13 bits used for the offset?

The remaining 19 bits are used for the page number. Signup and view all the answers

Where are the page tables typically stored?

The answer is not explicitly stated in the text, but in a typical system, page tables are stored in physical memory. Signup and view all the answers

What is temporal locality in the context of memory access?

Temporal locality refers to the tendency of programs to reuse the exact same memory addresses. Signup and view all the answers

What happens when a cache hit occurs?

When a cache hit occurs, the requested data is found in the cache, resulting in faster access times. Signup and view all the answers

What is the term for the process of finding data in the cache?

A cache hit is the term for finding data in the cache. Signup and view all the answers

What must be done when a cache miss occurs?

When a cache miss occurs, the system must access the page table in RAM to retrieve the requested data, and then store it in the cache for future use. Signup and view all the answers

What is the purpose of a page table in RAM?

The page table in RAM is used to translate virtual addresses to physical addresses. Signup and view all the answers

What is the purpose of a Translation Lookaside Buffer (TLB)?

TLB caches recently used Page Table Entries (PTEs) to speed up address translation by storing a small fraction of the page table in fast on-chip memory. Signup and view all the answers

How many bits are required for the offset in a virtual address with 4KB pages?

12 bits Signup and view all the answers

Describe the process of page translation in hardware (MMU) for each memory reference.

The steps include extracting the VPN (Virtual Page Number) from the VA (Virtual Address), calculating the address of the Page Table Entry (PTE), reading the PTE from memory, extracting the PFN (Page Frame Number), building the PA (Physical Address), and finally reading the contents of the PA from memory into a register. Signup and view all the answers

Why is the additional read required to get the physical page number from the page table considered bad?

The additional read increases the paging latency, impacting memory access speed due to the slow nature of RAM access. Signup and view all the answers

What is the significance of learning the PPN for a VPN during address translation?

Learning the Page Frame Number (PPN) for a Virtual Page Number (VPN) is crucial for mapping the virtual address to the corresponding physical address. Signup and view all the answers

How does the Array iterator example demonstrate the impact of page table access on memory references?

The example showcases how accessing elements of an array generates multiple memory references involving page table lookups, illustrating the effect of paging latency on performance. Signup and view all the answers