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Chapter 2 : Memory Management of Operating System - Coggle Diagram
Chapter 2 : Memory Management of Operating System
Function of Memory Manager
Preserve the space in main memory occupied by the operating system.
Memory Hierarchy
Register
Cache memory
Random access memory
USB memory
Hard drives
Tape backup
Jam Board
Characteristics of the different levels in the Hierarchy of Memory Management
Separates computer storage based on response time
There are 4 major levels
Internal
Main
On-line mass storage
Off-line bulk storage
Allocate a set of memory area to a program
Strategies in Memory Allocation
Fetch
To determine when a page is copied from disk to memory
Placement
To determine where the virtual pages to be loaded
First Fit
Is a fast algorithm
Worst Fit
Produces the largest left over block
Best Fit
Produces the smallest left over block
Replacement
To determine which virtual page must be removed from memory
Resident and Transient Routines
Resident Routines
Routines that directly support application programs as they run
Transient Routines
Stored on disk and read into memory only when needed.
Swapping Technique
Swap-out operations
Swap-in operation
The technique of temporarily removing a process from the memory of a computer system
Fixed Partion Memory Management
Divides the available space into fixed-length partitions, each of which holds one program
Segmentation
Structuring their programming in modules
Paging
A programs segments can vary in length
Process Management
The computer system today allow multiple programs to be loaded into memory
MS Outlook
IE
Calculator
MS word
Major System Resources type within a Computer System
CPU time
Memory
Hard Disc space
Network
Throughput
Electrical power
External devices
Resources
CPU Time
Memory
Files
Process State
Goes through a cycle called Process Life Cycled
States of process
New
Ready
Run
Blocked
Terminated
Interrupts
Is an electronic signal
Scheduling Concept
Is the basic of multitasking
Process Scheduling
To schedule process on a system
CPU Scheduler
None
Preemptive
Job Scheduler
Purpose of CPU Scheduler
Job Scheduler
Medium Term Scheduler
Short term scheduler
Scheduling Criteria
CPU utilisation
Throughput
Turnaround time
Waiting time
Response time
Optimization Criteria
Max
Min
Deadlock
Refers to a specific condition when two or more processare waiting for each other release a resource
Four conditions for deadlock to occur
Mutual Extension
Hold and Wait
No Preemption
Circular Wait
Threads
Types of Threads
Multithreading
Multiprogramming and Virtual Memory
The Processor Manager
Conventional Processes