This method of allocation may also require compaction from time to time Chained

This method of allocation may also require compaction

This preview shows page 5 - 7 out of 8 pages.

amount of sectors used. This method of allocation may also require compaction from time to time. Chained file allocation only allocates the first block with an entry in the FAT and after that there is a pointer that indicates the end of the file. This method is much like non-contiguous file allocation and only requires a single block but does not require that the files are stored contiguously. This method does require a long time to find the a block because it is not stored and cannot be calculated (Gallert, 2000). Indexed file allocation is similar to chained file allocation because it only stores the first block but the difference is that no data is stored and it has pointers to locate where it is stored on the storage media. This is typically why the first block has been named the index block. This allocation method also only requires the first block to be stored to the FAT. But, this method is much easier to retrieve the file because the first block has the location stored in it. But, each file uses a new sector. This method does make space usage greater because of this factor and wastes some of the secondary storage. Unix/Linux uses this storage method normally because now it does not really matter if extra storage space is used. Due to files being moved around it tends to make the hard drive work harder and slower. The file and device manager find the logical process of how files and data go together and move those files to sectors that are together in the FAT. This is achieved with a compaction algorithm (Gallert, 2000) . All versions of Windows, since Windows NT, use the NT or NTFS file system. The NT file system has added dependability, possession, and usage of the disk space. Prior to Windows NT Windows still used a FAT that is similar to that used by Linux/Unix. Windows also utilizes an ACL or DACL that is similar to the Unix/Linux file systems. According to (Microsoft, 2012), "A discretionary access control list (DACL) identifies the trustees that are allowed or denied access to a securable object. When a process tries to access a securable object, the system checks the ACEs in the object's DACL to determine whether to grant access to it. If the object does not have a DACL, the system grants full access to everyone. If the object's DACL has no ACEs, the system denies all attempts to access the object because the DACL does not allow any access rights." Some of the important features of the NT file system are: a b-tree directory scheme that keeps track of file cluster, file information is store within the clusters, large file support, An ACL, Integrated file compression, Unicode naming support, long and 8" x 3" name support, and Data security on both removable and fixed disks (Rouse, 2008). Windows NT stores files on the system and keeps track of them and then files are stored in clusters on the hard drive. According to (Rouse, 2008), "Using NTFS, the sizes of clusters range from 512 bytes to 64 kilobytes. Windows NT provides a recommended default cluster size for any given drive size. For example, for a 4 GB (gigabyte) drive, the default cluster size is 4 KB
(kilobytes). Note that clusters are indivisible. Even the smallest file takes up one cluster and a

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture