Storage Management - Introduction to Operating Systems
Subject and UNIT: Introduction to Operating Systems: Unit IV(a): Storage Management
Block device stores information in fixed size blocks. Operating system assigns address to each block. A Block device is one with which the driver communicates by sending entire blocks of data.
Storage Management - Introduction to Operating Systems
Subject and UNIT: Introduction to Operating Systems: Unit IV(a): Storage Management
Device management is the part of the operating system responsible for directly manipulating the hardware devices. Device management is implemented through stab the interaction of a device driver and interrupt routine.
Storage Management - Introduction to Operating Systems
Subject and UNIT: Introduction to Operating Systems: Unit IV(a): Storage Management
I/O devices are divided into three types: Human readable, Machine readable and Communication.
Storage Management - Introduction to Operating Systems
Subject and UNIT: Introduction to Operating Systems: Unit IV(a): Storage Management
Operating system is responsible for disk management.Disk formatting is of two types. a) Physical formatting or low level formatting. b) Logical formatting.
Storage Management - Introduction to Operating Systems
Subject and UNIT: Introduction to Operating Systems: Unit IV(a): Storage Management
Disk scheduling algorithms are used to reduce the total seek time of any request. I/O request issues a system call to the operating system. If desired disk drive or controller is idle then the request is served immediately.
Storage Management - Introduction to Operating Systems
Subject and UNIT: Introduction to Operating Systems: Unit IV(a): Storage Management
The actual details of disk I/O operation depend on the : 1. Computer system, 2. Operating system,3. Nature of the I/O channel and disk controller hardware.
Storage Management - Introduction to Operating Systems
Subject and UNIT: Introduction to Operating Systems: Unit IV(a): Storage Management
Magnetic disk drives are addresed as large 1- dimensional arrays of logical blocks, where the logical block is the smallest unit of transfer.
Storage Management - Introduction to Operating Systems
Subject and UNIT: Introduction to Operating Systems: Unit IV(a): Storage Management
A storage device is any device used in a computer to store information. It will retain this information when the computer is switched off.
Memory Management - Introduction to Operating Systems
Subject and UNIT: Introduction to Operating Systems: Unit III: Memory Management
Functions of memory manager Allocates primary memory to processes. Maps process address space to primary memory.
Memory Management - Introduction to Operating Systems
Subject and UNIT: Introduction to Operating Systems: Unit III: Memory Management
Thrashing occurs when a process does not have "enough" frames allocated to store the pages it uses repeatedly, the page fault rate will be very high.
Memory Management - Introduction to Operating Systems
Subject and UNIT: Introduction to Operating Systems: Unit III: Memory Management
In the last section, we discussed local page replacement policy. Now we have considered how to assign pages of a process logical memory to a fixed set of allocated frames.
Memory Management - Introduction to Operating Systems
Subject and UNIT: Introduction to Operating Systems: Unit III: Memory Management
When a page fault occurs, page replacement algorithms are used for loading the page in memory and no free page frame exist in memory.