Contagious Memory Allocation and Protection | Summary and Q&A

TL;DR

This video discusses the concept of contiguous memory allocation and the protection needs that must be addressed when allocating memory.

Key Insights

• 👤 The main memory of a computer needs to accommodate both the operating system and user processes.
• 📌 Protection mechanisms, such as location and limit registers, are used to prevent processes from accessing each other's memory.
• ❓ Contiguous memory allocation is a technique where processes are executed in continuous sections of memory.
• 🪡 Protection issues, such as preventing unauthorized access to memory, need to be addressed before discussing memory allocation schemes.
• 👋 The allocation scheme can be based on first fit, best fit, or worst fit strategies.
• ❓ The memory allocation scheme used in modern operating systems is a generalization of the fixed partition scheme.
• 🚫 Continuous memory is divided into fixed-size blocks or holes, and processes are allocated to these blocks.
• 🚫 The degree of multi-programming depends on the number of partitions or blocks available in the memory system.

Transcript

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Questions & Answers

Q: What is contiguous memory allocation?

Contiguous memory allocation is a memory allocation technique where a process is executed in a section of memory that is continuous with the section where the next process will be executed.

Q: Why is protection important in memory allocation?

Protection is important to prevent one process from accessing another process's memory. This ensures that each process can only access its own allocated memory.

Q: How is protection achieved in contiguous memory allocation?

Protection is achieved through the use of location and limit registers. The location register contains the smallest physical memory available to the system, and the limit register specifies the range of the size of the system memory where a process can be allocated.

Q: What is the purpose of the relocation register?

The relocation register contains the base address of the process, and the logical address is added to the relocation register to generate the actual physical address for execution.

Summary & Key Takeaways

• The main memory of a computer must accommodate both the operating system and user processes, so a process of allocation is needed.

• Contiguous memory allocation is a technique where a section of memory where a process is executing is continuous to the section where the next process will be executing.

• Before discussing the allocation scheme of contiguous memory, protection issues, such as preventing one process from accessing another process's memory, need to be solved.