Disk Defragmenter – HDD and SSD

By | December 30, 2016

SSD is replacing HDD at the present time, but it seems to me that it does not fit in the current time too much to write about disk defragmentation.
But I am currently using HDD, Let’s look at the difference between SSDs and the related program Auslogics Disk Defrag.

Principles of Disk Defragmentation
When you are using a computer, file save and deletion often occur. The “write” operation is performed on the storage space. In general, the write operation is performed in a continuous space, but if the space is not sufficient, the “write” is fragmented.

For example:
[Save file 1, blue 5 squares]

[Save file 2, 10 red squares]

[Delete file 1, blue 5 squares]

[Save file 3, light green 6 squares]

As mentioned above, the last one is fragmented as in the last result. It is the “disk defragmentation” which arranges it in a continuous state.

[After defragmenting a disk]

So let’s see what this defragmentation means on HDD and SDD.


Disk Defragmenter in HDD, SSD

For those who do not know what HDD and SSD are, here is a brief explanation.
In the case of HDD, it is a storage device that accesses the disk by motor and reads and writes the file.
As shown in the picture below, the access arm continues to move, accessing the physical disk and reading the desired data. Compared to a little exaggeration, it seems to be easy to understand if you think about the high speed (?) Version of the turntable to reproduce the LP version.

[Source: pixabay.com]

The following is an SSD. In the case of SSD, it is a flash memory based storage device. It is faster than HDD by improving the speed limit of such HDD, that is, the speed of reading and accessing the physical motor directly.

Since it is based on flash memory, there is no performance degradation factor like motor or access arm, and it is very fast because it is written and read by electric signal.


Anyway, both HDD and SSD-type disk fragmentation occur.

Since the HDD accesses the disk through the access arm using the motor as described above, if the fragmentation occurs, the performance deteriorates easily because it is necessary to read the data from the fragmented place.

On the other hand, there is no performance degradation in SSD even if fragmentation occurs because there is no such physical approach. Just because SSD reads through an electrical signal, fragmentation does not significantly affect performance. Rather, in the case of SSDs, defragmenting the disk will reduce the lifespan of the SSD, because SSDs have a limited number of “reads” and “writes”. It is not a big problem because the number of times it can be filled up by decades. However, if there is a lot of repetition of reading and writing like disk defragmentation, the degradation of life will be reduced incredibly. (As mentioned, there is no benefit in performance when defragmenting a disk, even though it will degrade its life.)

For this reason, you should not defragment your SSD and consider defragmenting your disk only if your storage device is a HDD.

How do I defragment my disk (HDD)?

Performing Disk Defragmenter

Disk defragmentation is primarily included in Windows’ programs.
[Accessories -> System Tools -> Disk Defragmenter]

Usage is not difficult, so I do not want to mention it.

In fact, here’s a basic defragmentation program for Windows. The reason for introducing ‘Auslogics Disk Defrag’ is that it is useful for users to defragment automatically during breaks when not using a PC.

Auslogics Disk Defrag

If you have ‘Disk Defrag Pro’ and ‘Disk Defrag Free’, you can use free trial or purchase if you want.

[Immediately after execution]

[Settings -> Scheduler]
Check “Defragment automatically” and click “How often?” Select “When PC is idle”.

I have tested it briefly and can see that defrag was running during the time when the user did not use the computer.


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