ABSTRACT FILE MANAGEMENT
By : / / Teknik Informatika
File management system is considered part of the operating system, Input to applications is by means of a file and Output is saved in a file for long-term storage. Objectives of File Management System are Meet the data management needs and requirements of the user, Guarantee that the data in the file are valid, Optimize performance, Provide I/O support for a variety of storage device types, Minimize or eliminate the potential for lost or destroyed data, Provide a standardized set of I/O interface routines and Provide I/O support for multiple users.
Minimal set of requirements for File Management are Each user may have controlled access to other users’ files, Each user should be able to create, delete, read, and change files, then user may control what type of accesses are allowed to the users’ files, Each user should be able to restructure the user’s files in a form appropriate to the problem, Each user should be able to move data between files, Each user should be able to back up and recover the user’s files in case of damage, Each user should be able to access the user’s files by using symbolic names.
Basic File System needs Physical I/O, Deals with exchanging blocks of data, Concerned with the placement of blocks and Concerned with buffering blocks in main memory. Then in Basic File System there is Long –Term Storage. Requirements for long-term storage are It must be possible to store a very large amount of information, The information must survive the termination of the process using it and Multiple processes must be able to access the information concurrently.
There is 2 Method for File Allocation. The First, File Allocation Method (1) needs Contiguous allocation, Single set of blocks is allocated to a file at the time of creation, Only a single entry in the file allocation table, Starting block and length of the file and External fragmentation will occur. And The Second, File Allocation Method (2) using Chained allocation. Chained Allocation needs Allocation on basis of individual block, Each block contains a pointer to the next block in the chain, Only single entry in the file allocation table.
Keywords : File Management System, Basic File System, File Allocation Method