Describe following in brief (i) Tools compliment representation (ii) LRU algorithm (iii) Memory management hardware (iv) LRU एकल प्रविष्टि (v) प्रत्यक्ष मैपिंग (vi) सहयकारी पेजिंग What is inter-processor communication and synchronization? Also describe inter-processor arbitration. इंटर-प्रोसेसर संचार और सिंक्रोनाइजेशन क्या है? इंटर-प्रोसेसर मध्यस्थता पर टिप्पणी करें।

(i) Tools Complement Representation

Tools complement representation refers to a method of representing negative binary numbers using the two's complement system. In this system, the most significant bit (MSB) is used as the sign bit: 0 indicates a positive number, and 1 indicates a negative number. To find the two's complement of a binary number, you invert all the bits (change 0s to 1s and 1s to 0s) and then add 1 to the least significant bit (LSB).

Example:

Binary number: 0101 (5 in decimal) Two's complement: 1011 (-5 in decimal)

Steps to find two's complement:

1. Invert all bits: 1010
2. Add 1 to the LSB: 1011

(ii) LRU Algorithm

LRU stands for Least Recently Used, and it is a cache replacement algorithm used in computer systems to manage the cache memory. The LRU algorithm evicts the least recently used items first. This approach is based on the assumption that items that have been used recently are more likely to be used again in the near future.

Steps of LRU Algorithm:

1. When a page is referenced, move it to the top of the list.
2. When a page needs to be replaced, remove the page at the bottom of the list (the least recently used page).
3. Insert the new page at the top of the list.

(iii) Memory Management Hardware

Memory management hardware refers to the physical components in a computer system that are responsible for managing memory resources. The main components include:

• Memory Management Unit (MMU): Translates virtual addresses to physical addresses.
• Cache Controllers: Manage the cache memory to improve access speed.
• TLB (Translation Lookaside Buffer): A cache that stores recent translations of virtual memory to physical memory addresses.

(iv) LRU एकल प्रविष्टि (LRU Single Entry)

LRU एकल प्रविष्टि refers to the implementation of the LRU algorithm where only one entry is considered for replacement at a time. This is a simplified version of the LRU algorithm and is not commonly used because it does not effectively utilize the cache memory.

(v) प्रत्यक्ष मैपिंग (Direct Mapping)

प्रत्यक्ष मैपिंग is a technique used in cache memory where each block of main memory maps to only one possible cache line. It is simple and fast but can lead to a high rate of cache misses if multiple memory blocks map to the same cache line.

Characteristics of Direct Mapping:

• One-to-one mapping between memory blocks and cache lines.
• Easy to implement.
• Can lead to cache thrashing if many blocks map to the same cache line.

(vi) सहयकारी पेजिंग (Cooperative Paging)

सहयकारी पेजिंग refers to a memory management scheme where the operating system and applications work together to manage memory pages. Applications can provide hints to the OS about their memory usage patterns, which can help the OS make better paging decisions.

Advantages of Cooperative Paging:

• Improved memory usage efficiency.
• Reduced page faults.
• Better overall system performance.

Inter-Processor Communication and Synchronization

Inter-processor communication (IPC) refers to the mechanisms used by different processors within a multi-processor system to communicate and coordinate their actions. Synchronization is the process of ensuring that multiple processors do not interfere with each other and that data consistency is maintained.

Methods of IPC:

• Shared Memory: Processors communicate by reading and writing to a shared memory space.
• Message Passing: Processors send messages to each other to communicate.

Synchronization Mechanisms:

• Locks: Prevent multiple processors from accessing a resource simultaneously.
• Semaphores: Counters that control access to shared resources.
• Barriers: Ensure that all processors reach a certain point before any can proceed.

Inter-Processor Arbitration

Inter-processor arbitration is the process of deciding which processor gets access to shared resources in a multi-processor system. This is necessary to avoid conflicts and ensure fair access to resources.

Arbitration Techniques:

• Daisy Chaining: Processors are connected in a series, and the first one to request access gets it.
• Independent Request: Each processor has a separate request line, and an arbiter decides who gets access.
• Priority-Based: Processors are assigned priorities, and the one with the highest priority gets access first.

Inter-processor arbitration ensures that all processors in a system can work together efficiently without interfering with each other's operations.