File system implementation in OS

-

 File system implementation :-

Numerous on-disk and in-memory configurations and structures are being used for implementing a file system. These structures differ based on the operating system and the file system but applying some general principles. Here they are portrayed below:
  • A boot control block usually contains the information required by the system for booting an operating system from that volume. When the disks do not contain any operating system, this block can be treated as empty. This is typically the first chunk of a volume. In UFS, this is termed as the boot block; in NTFS, it is the partition boot sector.
  • A volume control block holds volume or the partition details, such as the number of blocks in the partition, size of the blocks or chunks, free-block count along with free-block pointers. In UFS, it is termed as superblock; in NTFS, it is stored in the master file table.
  • A directory structure per file system is required for organizing the files. In UFS, it held the file names and associated 'inode' numbers. In NTFS, it gets stored in the master file table.
  • The FCB contains many details regarding any file which includes file permissions, ownership; the size of file and location of data blocks. In UFS, it is called the inode. In NTFS, this information gets stored within the master file table that uses a relational database (RDBM) structure, using a row per file.

Comments

Post a Comment

Popular posts from this blog

Paging in OS

-
Image
                      Paging  Paging is a fixed size partitioning scheme. In paging, secondary memory and main memory are divided into equal fixed size partitions. The partitions of secondary memory are called as  pages . The partitions of main memory are called as  frames . Each process is divided into parts where size of each part is same as page size. The size of the last part may be less than the page size. The pages of process are stored in the frames of main memory depending upon their availability. Different operating system defines different frame sizes. The sizes of each frame must be equal. Considering the fact that the pages are mapped to the frames in Paging, page size needs to be as same as frame size. Example- Consider a process is divided into 4 pages P 0 , P 1 , P 2  and P 3 . Depending upon the availability, these pages may be stored in the main memory fra...
Read more

Introduction of Digital computer

-
Image
INTRODUCTION Digital computer concept:- 1. Digital computers are designed to store, process and communicate information in digital form. 2. Digital computer is any of a class of digital devices capable of solving problems by processing information in discrete form. 3. It is used for processing data represented by discrete, localized physica signals, as the presence or electic current. 4.The main three components of digital computer:- >input:- The user gives a set of input data through input devices. >Processing :- The input data is processed with the help of CPU by well defined and finite sequence of step. >Output : - Some data available from the processing step are output to the user. TYPE OF DIGITAL COMPUTER :- 1.Microcomputer/Desktop computer 2.Minicomputer 3.Mainframe computer 4.Supercomputers Microcomputer :- 1.Microcomputer is also called a personal computer or desktop computer. 2.It includes a microprocessor, memory,...
Read more

Concept of segmentation in OS

-
Image
                 Segmentation :- A process is divided into Segments. The chunks that a program is divided into which are not necessarily all of the same sizes are called segments. Segmentation gives user’s view of the process which paging does not give. Here the user’s view is mapped to physical memory. There are types of segmentation: virtual memory segmentation  process is divided into a number of segments, not all of which are resident at any one point in time. 2 .Simple segmentation  – Each process is divided into a number of segments, all of which are loaded into memory at  run time, though not necessarily contiguously. There is no simple relationship between logical addresses and physical addresses in segmentation. A table stores the information about all such segments and is called Segment Table. Segment Table –  It maps two-dimensional Logical address into one-dimensional Physical address...
Read more