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In ghost for dos dose one need all 4 files

In ghost for dos dose one need all 4 files archive#
In ghost for dos dose one need all 4 files free#

Just as the space that is allocated to files must be managed ,so the space that is not currently allocated to any file must be managed. This allocation technique supports both sequential and direct access to the file and thus is the most popular form of file allocation. Allocation by blocks eliminates external fragmentation, whereas allocation by variable-size blocks improves locality.

Allocation may be on the basis of fixed-size blocks or variable-sized blocks. In this case, the file allocation table contains a separate one-level index for each file: The index has one entry for each block allocated to the file. It addresses many of the problems of contiguous and chained allocation. It supports only the sequential access of files.If the pointer of any disk block is lost, the file will be truncated.There is an overhead of maintaining the pointer in every disk block.Internal fragmentation exists in last disk block of file.There is no external fragmentation because only one block at a time is needed but there can be internal fragmentation but it exists only in the last disk block of file.

In ghost for dos dose one need all 4 files free#

Increase in file size is always possible if free disk block is available. Any free block can be added to the chain. Although pre-allocation is possible, it is more common simply to allocate blocks as needed. Again the file table needs just a single entry for each file, showing the starting block and the length of the file. Each block contains a pointer to the next block in the chain. Linked Allocation(Non-contiguous allocation) –Īllocation is on an individual block basis.

Also, with pre-allocation, it is necessary to declare the size of the file at the time of creation.Ģ.

Compaction algorithm will be necessary to free up additional space on disk.

External fragmentation will occur, making it difficult to find contiguous blocks of space of sufficient length.

For example, if a file starts at block b, and the ith block of the file is wanted, its location on secondary storage is simply b+i-1. It is also easy to retrieve a single block. Multiple blocks can be read in at a time to improve I/O performance for sequential processing. This method is best from the point of view of the individual sequential file. The file allocation table needs just a single entry for each file, showing the starting block and the length of the file. Thus, this is a pre-allocation strategy, using variable size portions. We have absolute or relative path name for a file.Ī single continuous set of blocks is allocated to a file at the time of file creation. Searching is efficient and also there is grouping capability.

Now,we can have same file name for different user.ĭirectory is maintained in the form of a tree.

Path name:Due to two levels there is a path name for every file to locate that file.

In this separate directories for each user is maintained.

Grouping problem: Users cannot group files according to their need.

Naming problem: Users cannot have same name for two files.

In this a single directory is maintained for all the users.

Grouping: Logical grouping of files can be done by properties e.g.

Naming: It becomes convenient for users as two users can have same name for different files or may have different name for same file.

Efficiency: A file can be located more quickly.

Information contained in a device directory are:Īdvantages of maintaining directories are: The directory is itself a file, accessible by various file management routines. Much of this information, especially that is concerned with storage, is managed by the operating system. The directory contains information about the files, including attributes, location and ownership.

In ghost for dos dose one need all 4 files archive#

Files attributes and its operations:Īttributes Types Operations Name Doc Create Type Exe Open Size Jpg Read Creation Data Xis Write Author C Append Last Modified Java Truncate protection class Delete Closeįile type Usual extension Function Executable exe, com, bin Read to run machine language program Object obj, o Compiled, machine language not linked Source Code C, java, pas, asm, a Source code in various languages Batch bat, sh Commands to the command interpreter Text txt, doc Textual data, documents Word Processor wp, tex, rrf, doc Various word processor formats Archive arc, zip, tar Related files grouped into one compressed file Multimedia mpeg, mov, rm For containing audio/video information Markup xml, html, tex It is the textual data and documents Library lib, a ,so, dll It contains libraries of routines for programmers Print or View gif, pdf, jpg It is a format for printing or viewing a ASCII or binary file.Ĭollection of files is a file directory.

ISRO CS Syllabus for Scientist/Engineer Exam.

ISRO CS Original Papers and Official Keys.

GATE CS Original Papers and Official Keys.