Presentation1.pptxPresentation1.pptxPres

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1. MEMORY MEMORY = STORAGE (Data and program are kept in computer(storage space)) OS MEMORY MANAGEMENT TASKS: Tracking memory Allocation Deallocation protection memory

2. Memory management “ Memory Management is the techniques or function of OS that handle how the memory allocated , used and freeded from processes ”. Functions of memory management: Allocation - OS decide how much memory they want Protection - Prevent one process memory does not access other memory Sharing - Allow safe sharing of memory location. Deallocation - free up the memory , when terminate. Example:Spotify – google chrome – whatsapp call.

3. hardware The os alone cannot manage memory. It depends on HARDWARE support(CPU AND MEMORY UNIT) to keep process and efficient. HARWARE PROVIDES TOOL LIKE : BASE REGISTER LIMIT REGISTER MMU TLB

4. ADDRESS BINDING The process of converting address are called address binding. before program in execution logical address physical address --------------  Types : Compile time Load time Execution time

5. Address space every process Logical address Or also called virtual addresss space cpu understood Ex:exam paper tnpsc (Q1 –Q10) Order:Q1 Q2 Q3 Physical address Actual location in the Ram Ex:exam paper tnpsc (Q1 –Q10) Order:Q1 Q3 Q2

6. Dynamic loading and dynamic linking Dynamic loading: Parts of the program are loaded only when needed. Example:whatsapp video call Dynamic linking: Common libraries are not copied into every program ,instead a single shared version is linked at runtime. Example: in android, library are shared- between whatsapp , youtube and spotify

7. swapping The process of moving from main memory to secondary memory is called swapping. example: suppose on your phone: i ) open whatsapp ---  loaded in ram Ii)then open youtube --also added Iii)then open instagram -- ram gets full OS decide: i ) whatsapp moves to disk Ii) instagram --- in ram,and return the wa in ram that is swapping

8. Memory allocation The process of assigning portion of computer memory (RAM) to process when they need it. [ os decide where the program placed in ram and how much memory to give] Types of memory allocation: 1. contiguous memory allocation 2. non-contiguous memory allocation

9. Contiguous memory allocation Each process allocat continuous memory allocation Overall process is stored in one place. Ex:suppose ram = 100mb P1 = 10mb P2= 30mb P3= 10 mb (they stored in continous memory) If p2 is finished a 30mb(hole) is left, they donot allowed any new process Non-contiguous memory allocation A process memory bis divided into parts and placed at different locations in the ram. Two techniques: 1. paging 2. segmentation Ex: if you want to store 10 mb -  it split into 3 parts and stored in the memory. xxx xxx xxx