Podcast
Questions and Answers
What is the purpose of sections and supersections in ARM virtual memory address translation?
What is the purpose of sections and supersections in ARM virtual memory address translation?
- To increase the size of the translation table
- To allow mapping of a large region of memory while using only a single entry in the TLB (correct)
- To slow down the memory access process
- To reduce the size of the TLB
What is the primary function of the Scheduler in the depicted system?
What is the primary function of the Scheduler in the depicted system?
- To manage memory allocation
- To allocate CPU time to processes (correct)
- To control input/output operations
- To handle interrupts
What is the size of a supersection in ARM virtual memory address translation?
What is the size of a supersection in ARM virtual memory address translation?
- 16-MB blocks of main memory (correct)
- 1-MB blocks of main memory
- 64-kB blocks of main memory
- 4-kB blocks of main memory
What is the state of Process A in figure (a)?
What is the state of Process A in figure (a)?
What is the function of the level 1 table in ARM virtual memory address translation?
What is the function of the level 1 table in ARM virtual memory address translation?
What is the size of a large page in ARM virtual memory address translation?
What is the size of a large page in ARM virtual memory address translation?
What is the role of the Service Handler in the system?
What is the role of the Service Handler in the system?
What is the state of Process B in figure (c)?
What is the state of Process B in figure (c)?
What is the purpose of the translation table in ARM virtual memory address translation?
What is the purpose of the translation table in ARM virtual memory address translation?
What is the size of a small page in ARM virtual memory address translation?
What is the size of a small page in ARM virtual memory address translation?
What is the primary function of the Interrupt Handler in the system?
What is the primary function of the Interrupt Handler in the system?
What is the state of Process A in figure (b)?
What is the state of Process A in figure (b)?
What is the function of the level 2 table in ARM virtual memory address translation?
What is the function of the level 2 table in ARM virtual memory address translation?
How much memory is required by the level 2 table in ARM virtual memory address translation?
How much memory is required by the level 2 table in ARM virtual memory address translation?
What is a monitor in the context of computer systems?
What is a monitor in the context of computer systems?
Why is memory protection necessary in a computer system?
Why is memory protection necessary in a computer system?
What happens when a processor encounters a privileged instruction while executing a user program?
What happens when a processor encounters a privileged instruction while executing a user program?
What is the purpose of a timer in a computer system?
What is the purpose of a timer in a computer system?
What happens when the timer expires?
What happens when the timer expires?
What is the purpose of interrupts in a computer system?
What is the purpose of interrupts in a computer system?
What type of instructions can only be executed by the monitor?
What type of instructions can only be executed by the monitor?
What is the role of the monitor when a user program encounters an error?
What is the role of the monitor when a user program encounters an error?
What is the main purpose of the Inverted Page Table Structure?
What is the main purpose of the Inverted Page Table Structure?
What happens when the CPU checks the TLB and does not find a page table entry?
What happens when the CPU checks the TLB and does not find a page table entry?
What is the function of the hash function in the Inverted Page Table Structure?
What is the function of the hash function in the Inverted Page Table Structure?
What is stored in each entry of the Inverted Page Table?
What is stored in each entry of the Inverted Page Table?
What is the purpose of the Lookaside Buffer (TLB)?
What is the purpose of the Lookaside Buffer (TLB)?
What happens when the OS instructs the CPU to read a page from disk?
What happens when the OS instructs the CPU to read a page from disk?
What is the purpose of the page fault handling routine?
What is the purpose of the page fault handling routine?
What is the main advantage of using an Inverted Page Table?
What is the main advantage of using an Inverted Page Table?
What does the Base field in a segment descriptor define?
What does the Base field in a segment descriptor define?
What is the function of the D/B bit in a code segment?
What is the function of the D/B bit in a code segment?
What does the Granularity bit (G) control?
What does the Granularity bit (G) control?
What is the maximum segment size limit when the Granularity bit is set to 1?
What is the maximum segment size limit when the Granularity bit is set to 1?
What is the function of the S bit in a segment descriptor?
What is the function of the S bit in a segment descriptor?
What is the function of the Accessed bit (A) in a page table?
What is the function of the Accessed bit (A) in a page table?
What is the function of the Dirty bit (D) in a page table?
What is the function of the Dirty bit (D) in a page table?
What does the Page Frame Address provide?
What does the Page Frame Address provide?
Study Notes
Virtual Memory Address Translation
- The ARM supports memory access based on either sections or pages
- Sections consist of 1-MB blocks of main memory
- Supersections (optional) consist of 16-MB blocks of main memory
- Large pages consist of 64-kB blocks of main memory
- Small pages consist of 4-kB blocks of main memory
Translation Tables
- Level 1 table holds level 1 descriptors that contain the base address and translation properties for a section and supersection
- Level 2 table holds level 2 descriptors that contain the base address and translation properties for a small page or a large page
- Level 2 table requires 1kB of memory
Desirable Hardware Features
- Memory protection ensures user programs do not alter the memory area containing the monitor
- The processor hardware detects errors and transfers control to the monitor
- Privileged instructions can only be executed by the monitor
- I/O instructions are privileged, so the monitor retains control of all I/O devices
- Timer is used to prevent a job from monopolizing the system
Interrupts
- Interrupts give the OS more flexibility in relinquishing control to and regaining control from user programs
- Timer interrupts occur when the timer expires
Operating System
- Operatingsystem has three components: service handler, scheduler, and interrupt handler
- The scheduler decides which job to execute next
- Interrupt handler handles interrupts and returns control to the scheduler
Inverted Page Table Structure
- Inverted page table structure is used to translate virtual addresses to physical addresses
- Each entry in the inverted page table corresponds to a physical memory frame
- The page table contains a hash function, page number, and control bits
Operation of Paging and Translation
- The Lookaside Buffer (TLB) is used to cache recently accessed page table entries
- The CPU checks the TLB for a page table entry before accessing the page table
- If the page table entry is not in the TLB, a page fault occurs and the OS handles the page fault
x86 Memory Management Parameters
- Segment descriptor (segment table entry) contains the base address, D/B bit, descriptor privilege level (DPL), granularity bit (G), limit, S bit, and segment present bit (P)
- Page directory entry and page table entry contain the accessed bit (A), dirty bit (D), and page frame address
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Description
This quiz covers the concepts of virtual memory address translation in ARM architecture, including sections, supersections, and translation lookaside buffer (TLB).
