Guest author: Jyoti Roy
About this guest author: Jyoti Roy is a Mac user and she loves to share her ideas on Mac utilities like defragment Mac, speed Up, cleaning tool for Mac users etc. over internet so that she could explore her knowledge with other people.
Many of you might have a question in your mind that is it necessary to defragment Mac OS X even though its developers refuse
for any such requirement on Macs. However, the need for fragmentation to be dealt with arises when your Mac slows down like hell, files take long time to open, applications often are crashed, also it does not even boot normally.
Since the HFS+ file system in Mac OS X has inbuilt features to defrag Mac drive, it does not really make sense to defragment you Mac system manually. In reality,
“Fragmentation is a phenomenon that occurs due to inefficient utilization of the storage blocks on the hard drives. Besides, the term fragmentation refers to the wasted storage blocks as well”
Fragmentation not only causes wastage of the storage blocks, but increases the response time of data as well. By the way, those who have been through the annoying chore of fragmentation understand why it is required.
Defrag Mac refers to the process of improving the performance of the hard drive by rearranging all physical memory blocks in a logical order and removing the fragments.”
This not only minimizes the response time of data, but also makes wasted storage blocks available to be used again. To defragment boot volume on your Mac, you can use boot volume defragmenter application. Now, before we further discuss defragmentation and the ways it improves the performance of computers, let us go through fragmentation in detail.
In addition to the minor glimpse shown above, fragmentation is a poor state of the hard drives in which response time of the files is increased considerably due to scattering of their segments. Since the segments of a large single file are stored non-contiguously, it takes even more time to gather response from each of these segments as compared to those that are stored contiguously in a logical order. Fragmentation not only leads to wastage of storage space, but it is a major cause of the poor performance of computers as well.
2. What causes Fragmentation
Though you cannot prevent fragmentation to occur, you can certainly find some ways to avoid germination of the factors responsible for it. If we talk about the causes of fragmentation, following are the major ones causing fragmentation on Macs:
• Inefficient Storage allocation Algorithms
In Mac OS X, the HFS+ file system is responsible for allocating storage space to the segments of the files. For this, it splits up the hard drive space into blocks of certain sizes. When you save a file on your Mac, HFS+ file system breaks this file into segments, irrespective of the sizes of the storage blocks. Due to this, contiguous streams of data contain unoccupied storage blocks that are termed as fragments. These unoccupied storage blocks are smaller as compared to that of the file segments they are allocated.
• Repeatedly moving large files
Based on the size of the files, HFS+ file system may or may not have to break them into segments. This means that whenever the size of a file is found to be larger than that of the storage block it is allocated, file system has to break this file into segments in order to store it on the hard drive. Besides, when you move such a large file from one location to another on your Mac, the large amount of freed up space is not reused to store new files, but it remains empty. Slew of such blocks cause scattering of data (i.e. fragmentation).
3. Types of Fragmentation
Since HFS+ file system is intelligent enough, it splits up storage space on the hard drives into blocks to store segments of the files. Due to inefficient storage space allocation algorithm, if a segment of the file gets storage block larger then that particular block will contain free space that cannot be reused. Likewise, slew of storage blocks can have free spaces. Now, since free spaces are inside the contiguously allocated regions, it is termed as internal fragmentation.
Some storage space allocation algorithms inefficiently utilize storage blocks and are unable to arrange them in a logical order. In such a situation, even though free blocks are available, they are practically impossible to allocate to data segments due to their small size. Now, since empty spaces are outside the contiguously allocated region, it is thus termed as external fragmentation.
In case of external fragmentation, due to randomly or inefficiently utilized storage blocks, segments of a file become scattered, which is termed as data fragmentation.
4. Mac file system dealing with Fragmentation
According to a statement from Apple’s spokesperson, Macs do not need defragmentation since they use HFS+ file system for hard drive formatting, which is intelligent enough to deal with fragmentation. However, this statement if applicable only to the files of up to 20MB of size (i.e. HFS+ file system can defragment Mac files having maximum 20MB size). For this, every single file is scanned individually whenever they are opened. In case a file is found to have 8 fragments, it will be defragmented automatically. However, it cannot scan and defragment the files above 20MB. This also means that to defrag large files (>20MB) on your Mac, you have to use an external application.
Many of you complain like, defragmentation compressed my precious files; I am unable to open some of my files, as they are shown as corrupt after defragmentation. In such a situation, you might be thinking is it safe to defragment boot volume on your Mac? Since thousands of system files are under repeated execution, even a minor glitch (i.e. corruption or failure of even a single system file) may cause failure of your Mac. Due this, you may not be able access you precious files. To avoid such an issue, you can use professional boot volume defragmenter on your Mac. Since Mac OS X does not have any inbuilt defragmentation tool, you have to use a professional Mac disk defragmentation application.
Even though there is nothing like a compression or destruction mechanism involved in Mac disk defragmentation process, you can avoid all possible risks using such an advanced application.