How data in RAM of a certain process is protected?

A memory protection key (MPK) mechanism divides physical memory into blocks of a particular size (e.g., 4 KiB), each of which has an associated numerical value called a protection key. Each process also has a protection key value associated with it.

How in the primary memory one process is protected from another process?

In this type of allocation, relocation-register scheme is used to protect user processes from each other, and from changing operating-system code and data. Relocation register contains value of smallest physical address whereas limit register contains range of logical addresses.

How does memory management unit protect content in a process?

The MMU provides per process address translation of linear (virtual) address to physical addresses. Protection. The MMU entries provide privilege checking and read/write protection of memory. Privilege checking ensures that the processor has the correct privilege level to access a particular memory region.

How does memory protection unit work?

MPU monitors transactions, including instruction fetches and data accesses from the processor, which can trigger a fault exception when an access violation is detected. The main purpose of memory protection is to prevent a process from accessing memory that has not been allocated to it.

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Which two methods are used to protect the reliability of memory?

A, C. Parity memory and ECC have an additional memory chip added for parity. They are both methods used to protect the reliability of memory.

Which registers are used to protect the main memory?

Pointers to memory segments on x86 processors can also be stored in the processor’s segment registers. Initially x86 processors had 4 segment registers, CS (code segment), SS (stack segment), DS (data segment) and ES (extra segment); later another two segment registers were added – FS and GS.

What is difference between physical and logical cache?

The basic difference between Logical and physical address is that Logical address is generated by CPU in perspective of a program. On the other hand, the physical address is a location that exists in the memory unit. … The set of all logical addresses generated by CPU for a program is called Logical Address Space.


A computer’s memory management unit (MMU) is the physical hardware that handles its virtual memory and caching operations. The MMU is usually located within the computer’s central processing unit (CPU), but sometimes operates in a separate integrated chip (IC).

What are the main components of memory management?

Memory management resides in hardware, in the OS (operating system), and in programs and applications. In hardware, memory management involves components that physically store data, such as RAM (random access memory) chips, memory caches, and flash-based SSDs (solid-state drives).

Why paging is used in OS?

Paging is used for faster access to data. When a program needs a page, it is available in the main memory as the OS copies a certain number of pages from your storage device to main memory. Paging allows the physical address space of a process to be noncontiguous.

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Why Semaphore is used in OS?

Semaphore is simply a variable that is non-negative and shared between threads. This variable is used to solve the critical section problem and to achieve process synchronization in the multiprocessing environment. This is also known as mutex lock. It can have only two values – 0 and 1.

What is difference between segmentation and paging?

It is variable size partitioning theme. like paging, in segmentation, secondary and main memory are not divided into partitions of equal size. The partitions of secondary memory area unit known as as segments.

Difference between Paging and Segmentation:

S.NO Paging Segmentation
10. Paging is invisible to the user. Segmentation is visible to the user.

What is MMU and MPU?

Literally speaking, MMU is ‘Memory Management Unit’ while MPU is ‘Memory Protection Unit’. … MMU is used for many functions primarily Virtual Memory (i.e. translation of virtual address to physical address) and memory protection. But MPU is used for memory protection only.

What is micro processing unit?

The microprocessor is the central unit of a computer system that performs arithmetic and logic operations, which generally include adding, subtracting, transferring numbers from one area to another, and comparing two numbers. It’s often known simply as a processor, a central processing unit, or as a logic chip.