Inside Out of SSD Drives

Technology Overview, November 5, 2017

Different from the traditional hard disk drives, the data in the SSD is not saved on a magnetic surface, but it is stored inside the NAND flash memory chips. By the designing, an SSD drive is formed by one motherboard, some memory chips (the number of chips depends on the size of the drive in GB) and one controller which is to control the operations of the drive. SSDs memory is of non-volatile nature, which means that it can retain the data even in the time of no power. There are 3 types of NAND chips:

  1. Single Level Cell (SLC) – 1 bit data per cell
  2. Multi-Level Cell (MLC) – 2 bits data per cell
  3. Triple Level Cell (TLC) or it is also called as the 3-bit MLC – 3 bits data per cell

More the number of levels in a cell; more are the bits that can be stored in that cell and higher is the capacity of the chips. Thanks to the technological advancements, we are endowed with SSD drives with many GB storage space today at affordable prices. However, this has a downside too – if we add more bits to the cell, it inversely reduces the cell’s durability, reliability as well as its performance.

The writing operations on an SSD drive wears out its memory cells, thereby, reducing the life of the drive.

Precautions to Keep an SSD Drive Healthy for a Longer Time

  • Try Avoiding the Defragmentation of the Drive: You do not need using the defrag utility for reducing the SSD file fragmentation. This operation of defragmentation is usually used on the traditional hard disks, which spin, for the purpose of reducing the movements & time that is utilized by the heads for accessing various clusters of the fragments of a particular file. However, on an SSD drive, all memory cells possess similar access time and thus, this defragmentation operation is totally unrequited and can also be harmful sometimes because the moving fragments in this drive need to write operations which cause the wear and tear of the SSD drive.
  • Never Saturate the Drive’s Storage Capacity: Never attempt using the drive over its capacity limit. Most manufacturers employ over-provisioning in the drives where a permanent free space is reserved (mostly 10%), which is inaccessible to the user or even to the OS, and this space is a kind of buffer for storing data temporarily.
  • Try Enabling TRIM in Your OS: Most SSDs tend to integrate the GC, garbage-collection (GC) function, which is a function used to preparing the memory cells of SSDs for receiving fresh data. In most new OS versions, the TRIM command makes garbage-collection more efficient. By using this TRIM command, the OS sends the notification to the SSD drive while the data is getting marked as erasable/invalid and the OS sends this TRIM command to the SSD drive each time the user deletes a file. Ensure that your OS supports this TRIM command and also make sure to check that this TRIM command is active.
  • Use SSD Where It Is Useful: Surely, a great advantage of using SSD drives is their high data reading speed. But, writing operation causes the wear and tear of the drive and is slow; so, before writing some block, it has to be deleted.

A Suggestion in the End

Always try making a backup copy of your crucial data regularly. Using SSD does not rule out the consideration of unexpected and unfortunate events like voltage variations, shocks, human errors and many other such incidents which cause data damages and sometimes even make the data totally inaccessible.