Allocation of Free Disk Blocks in UNIX using Bitmaps
S.Ayesha Firadose1, S.Khadeeja Banu2
1S.Ayesha firadose, Computer Science and Engineering, Srenivasa Institute of Technology and Management Studies, Chittoor, Andhra Pradesh, India.
2S.Khadeeja Banu, Computer Science and Engineering, Srenivasa Institute of Technology and Management Studies, Chittoor, Andhra Pradesh, India.
Manuscript received on September 24, 2013. | Revised Manuscript received on October 17, 2013. | Manuscript published on October 30, 2013. | PP: 71-72 | Volume-3, Issue-1, October 2013. | Retrieval Number: F2120082613/2013©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: The utility program mkfs organizes the data blocks of a file system in a linked list. Each link of the list is a disk block that contains an array of free disk block numbers, and one array entry is the number of the next block of the linked list. The file system super block contains an array that is used to cache the numbers of free disk blocks in the file system. Because of this technique, there is a wastage of memory. To overcome this disadvantage we can use bitmaps. In bitmaps only one bit can be used to indicate the status of disk block. Using this technique memory space is utilized efficiently and wastage of processor time for reading one or more disk blocks in main memory is reduced.
Keywords: Disk block, Super block, Bit map.