Memory Management Strategies I - Comprehensive Foundations

This section provides a comprehensive overview of memory management strategies, focusing on hardware mechanisms, address translation, and the challenges of memory allocation.

Background - The Essential Memory Landscape

This section explores fundamental memory management concepts, including address translation and memory allocation strategies, to facilitate efficient utilization of memory in operating systems.

Basic Hardware: The Bridge Between Logical And Physical Addresses

This section explains the critical role of address translation hardware in memory management, highlighting the differences between logical and physical addresses.

Address Binding: The Act Of Translation

Address binding is the process of mapping logical addresses generated by the CPU to physical addresses in memory.

Compile Time Binding

Compile time binding is a memory management technique where the physical address of a program is determined at compile time, resulting in direct mapping of logical addresses to physical addresses.

Load Time Binding

Load time binding refers to the process of linking a program's logical addresses to physical addresses when the program is loaded into memory.

Execution Time (Run Time) Binding

Execution time binding is a flexible method of translating logical addresses to physical addresses during program execution.

Logical Vs. Physical Address Space

This section explains the distinction between logical and physical address spaces and the mechanisms of address binding in memory management.

Relocation Register (Base Register) And Limit Register

The section describes the functionality of the Relocation Register and Limit Register in translating logical addresses to physical addresses during memory management.

Dynamic Loading And Linking: Optimizing Program Startup And Resource Use

Dynamic loading and linking are techniques that enhance memory utilization and program flexibility by delaying the loading and linking of code until needed during execution.

Dynamic Loading

Dynamic loading improves program efficiency by loading only necessary routines during execution rather than all at once.

Dynamic Linking

Dynamic linking allows programs to reference library routines at runtime rather than at compile time, enhancing flexibility and memory efficiency.

Swapping: A Basic Memory Extension Technique

Swapping is a fundamental technique in memory management that enables the operating system to temporarily transfer processes from main memory to secondary storage, thereby enhancing multiprogramming capabilities.

Contiguous Memory Allocation - Simple Structures, Complex Problems

Contiguous memory allocation is a straightforward memory management method where processes receive a single, continuous block of memory, yet presents challenges including fragmentation and limited flexibility.

Fixed-Partition Allocation (Static Partitioning)

Fixed-partition allocation involves dividing the main memory into a fixed number of partitions that can each hold one process, presenting advantages in simplicity but challenges in internal fragmentation and flexibility.

Variable-Partition Allocation (Dynamic Partitioning)

Variable-partition allocation is a dynamic memory management technique that allocates physical memory to processes in sizes tailored to their requirements, managing memory holes efficiently.

Strategies For Hole Selection (Placement Algorithms)

This section discusses various strategies for hole selection in dynamic partitioning memory management, including First-Fit, Best-Fit, and Worst-Fit algorithms.

Paging - The Non-Contiguous Revolution

Paging is a memory management technique that allows non-contiguous allocation of physical memory to processes, effectively eliminating external fragmentation and simplifying memory allocation.

Basic Method

The Basic Method section introduces the fundamentals of paging—a non-contiguous memory management strategy that eliminates external fragmentation by dividing logical and physical memory into fixed-size blocks called pages and frames respectively.

Address Translation (The Core Mechanism)

Address translation is the essential process by which logical addresses used by programs are converted into physical addresses in memory, ensuring correct memory access and process isolation.

Hardware Support (Tlb - Translation Look-Aside Buffer)

The section discusses the Translation Look-aside Buffer (TLB), a hardware cache that optimizes address translation in paging systems, allowing faster memory address retrieval.

Protection

This section outlines how paging provides robust memory protection through page tables, access control mechanisms, and shared pages.

Shared Pages

Shared pages in memory management allow multiple processes to use the same physical page, optimizing memory usage.

Segmentation - The Logical View Of Memory

Segmentation organizes a program's logical address space into variable-sized segments, closely aligning memory management with programmers' views of a program.

Basic Method

This section explores the foundational concept of paging, highlighting how it enhances memory management by allowing non-contiguous allocation.

Address Translation

Address translation is the process of converting logical addresses generated by a CPU to physical addresses in memory, ensuring appropriate memory access for processes.

Hardware Support

This section explores the hardware mechanisms that support memory management in operating systems, highlighting address translation and related concepts.

Segmentation With Paging (Segmented Paging / Paged Segmentation)

This section outlines the hybrid memory management strategy of segmentation with paging, combining the benefits of both approaches.