Mac Disk Fragmentation and its Resolution on Mac OS X Lion

Hard drives are the common source of data storage on computers, which are available as both internal and external media. Despite many advantageous features, hard drives are subject to fragmentation over time. Actually, the memory of a hard drive is segregated into small blocks of certain dimensions (divisible by 2, 4, 8, 16, 32, etc.). When a file is to be saved on the hard drive, operating system splits it up into segments of small sizes in order to allocate the memory blocks.


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Causes of Fragmentation

Fragments are the portions of data files that are produced due to poor memory allocation system and repeated shifting of files on the hard drive.

Based on the memory allocation system brought into play by Mac OS X, segments of a file may or may not get hold of the allocated blocks. For example, if the size of a segment is smaller than that of the allocated block, then the segment does acquire the block, but rest of the space remains free. Such state of the memory is termed as internal fragmentation. On the other hand, if the size of a segment is greater than that of the allocated block, then the segment is not able to fit into the block it is allocated. As a result, that complete block remains free or unoccupied, and this is referred to as external fragmentation.

Additionally, because of the free spaces in memory, data segments are located at different locations. For example, you may write some new data in a file that is already saved on the hard drive. In such situation, new data does not get memory block next to the one where the file ends, but at any other location, and thus data fragmentation occurs.

What is the Solution

If fragmentation defines a deprived state of the memory, then the likely solution is termed as defragmentation. A few of the computer operating systems (i.e. Windows) offer inbuilt disk defragmentation tool in order to reorganize the memory blocks. Thus, defragmentation is referred to as a memory reorganization mechanism that results in a random logical arrangement of the memory blocks. However, Mac OS X does not facilitate any such inbuilt tool in Disk Utility.

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You might be running Mac OS X Lion or Mountain Lion, having faith on Apple’s statements that Mac does not need defragmentation. The HFS+ files system format used on Mac OS X Lion and Mountain Lion is smart enough to scan the files every time they are opened, and defragment files if they are found as highly fragmented (more than 8 fragments). The statement is genuine, though. However, the concerned files are less than 20MB in size. What about the files those are above 20MB of size? Here you need to use a defragmentation software even on your Mac OS X Lion and Mountain Lion.

Initially, defragmentation software analyzes the memory, gets familiar with the memory allocation system, and then starts reorganizing the memory blocks containing data segments in a random logical order. Besides, every single free space or unoccupied block is eliminated from the contiguous physical arrangement of the memory blocks. These free spaces are collected to form larger blocks, which are reused afterwards. Since the overall rearrangement of memory relies on the defragmentation software you put into action, it is recommended to bring a reliable and efficient one into play.

  • Pean

    Great job once again! Thumbs up=)