What is Indexed allocation method in file?

What is Indexed allocation method in file?

The Indexed allocation method is another method that is used for file allocation. In the index allocation method, we have an additional block, and that block is known as the index block. For each file, there is an individual index block. In the index block, the ith entry holds the disk address of the ith file block.

What is file allocation table give an example?

The file system uses an index table stored on the device to identify chains of data storage areas associated with a file, the File Allocation Table (FAT). The FAT is statically allocated at the time of formatting. The table is a linked list of entries for each cluster, a contiguous area of disk storage.

Which file allocation method is best?

Explanation: The indexed allocation method is the best file allocation method because it removes the problem of contiguous and linked allocation.

What is meant by file allocation?

The allocation methods define how the files are stored in the disk blocks. There are three main disk space or file allocation methods. Contiguous Allocation. Linked Allocation.

What are the advantages of indexed allocation method?

Advantage:  Indexed allocation supports direct access and does not suffer from any external fragmentation. Disadvantage:  Indexed allocation suffers from the problem of wasted space.

What is the purpose of file allocation table?

A file allocation table (FAT) is a table that an operating system maintains on a hard disk that provides a map of the clusters (the basic units of logical storage on a hard disk) that a file has been stored in.

How does indexed allocation work?

Instead of maintaining a file allocation table of all the disk pointers, Indexed allocation scheme stores all the disk pointers in one of the blocks called as indexed block. Indexed block doesn’t hold the file data, but it holds the pointers to all the disk blocks allocated to that particular file.

What is the indexed allocation method?

The Indexed allocation method is another method that is used for file allocation. In the index allocation method, we have an additional block, and that block is known as the index block. For each file, there is an individual index block. In the index block, the ith entry holds the disk address of the ith file block.

What is a File Allocation Table?

File allocation table tries to solve as many problems as possible but leads to a drawback. The more the number of blocks, the more will be the size of FAT. Therefore, we need to allocate more space to a file allocation table. Since, file allocation table needs to be cached therefore it is impossible to have as many space in cache.

What are the disadvantages of indexing a file?

Disadvantages: The pointer overhead for indexed allocation is greater than linked allocation. For very small files, say files that expand only 2-3 blocks, the indexed allocation would keep one entire block (index block) for the pointers which is inefficient in terms of memory utilization.

What is the difference between linked and indexed memory allocation?

The pointer overhead for indexed allocation is greater than linked allocation. For very small files, say files that expand only 2-3 blocks, the indexed allocation would keep one entire block (index block) for the pointers which is inefficient in terms of memory utilization.