Owlcom software
basadO wlCom  Software
Let's Owl manage your files
Welcome Screenshots Buy now Download Write to Owl Subscribe to news FAQ Links

Organization of the file system

Block Size A logical block size plays an important role. In some systems (Unix), it may be raised during formatting. The small size of the block would result in each file will contain a lot of blocks. Reading block by delays in the search and rotation, thus many of the file blocks to be read slowly. Large blocks provide higher speed exchange with the disk, but because of internal fragmentation (each file takes integer units, and an average of the last half of the block disappears) reduced the percentage of useful disk space. In systems with the organization of memory page has a similar problem with the size of the page. Studies have shown that most of the files have a small size (in Unix approximately 85% of files are less than 8 KB size and 48% less than 1 kb). Fig. 12.5 shows two curves: one shows a decreasing degree of recycling drive (as a percentage) with the growing size of the block, and the second-increasing speed reader information. They intersect in the region of 3 K. Normal compromise choice block of 512 B, 1 K, 2 K. The structure of the file system on drive Consideration of the working methods of disk space gives a general idea of the office together, the data needed to describe the file system. The structures of the file system data model, such as Unix, in one of the disk, thus, may consist of 4 major parts: At the beginning of the section is superblock that contains a general description of the file system, such as: Type of file system The size of the file system in the blocks The size of the array index nodes The size of the logical unit I.t. e. Described data structures are created on the disk from its formatting (such as utilities format, makefs, etc.). Their presence offers data on the disk as a file system, rather than as a normal sequence of blocks. In modern OS file systems to improve the sustainability superbloka supports multiple copies. In some versions of Unix superblock also included data structures that control the distribution of disk space, resulting in superblock continuously subjected to modification, reducing the reliability of the file system as a whole. Allocation of data structures, describing disk space, in a separate part is a correct decision. Array index nodes (ilist) contains a list of indices relevant files of the file system. The size of the array index is determined by the administrator of knots when installing the system. The maximum number of files that can be set up in the file system, the number of available nodes index.
Next part
Welcome    Screenshots    Download    Buy now Write to Owl    Subscribe to Owl news   FAQ   Links  
Copyright 2004-2008 OwlCom Software .

OISV - Organization of Independent Software Vendors - Contributing Member Software Submit .NET - FREE and PREMIUM search engines submission and software submission and software promotion service. Owl Commander
Locations of visitors to this page

Valid HTML 4.01 Transitional