Using SSD is the finest option to upgrade your old computer. To get better performing computer, people now prefer SSD over HDD. But have you ever wondered why and how the former works better than the latter?
In this post, we will discuss how SSD works and more!
First, let us understand the basic functionality of the computer and how memory operates.
Computer memory consists of three parts:
- Data drive
Three of them play an important role in computer’s working mechanism.
- Cache is inner layer of the memory unit. Computer uses cache for data computations and operations. Data accessing is faster as the electrical pathways going to the cache are the smallest. Although, the cache is very trivial so the data on it, is constantly overwritten.
- Memory is the mid layer, which is also known as RAM (Random Access Memory). This is the space where computer keeps data associated to active processes and programs.
- Third one that comes is Data drive. It is considered permanent storage space for data. This space is used to store music files, documents, Movies, programs and more.
So, whenever you open a file, the computer loads it from data drive to RAM. Just as the mechanism is different, there is a huge speed difference. RAM and cache work in nanoseconds, data drive of HDD works in milliseconds. Hence defining the speed of your computer with traditional HDDs. However, in case of SSD, they are faster. That’s why it takes lesser time to load processes and programs on the computer with SSDs.
Working Mechanism Of SSD:
SSDs are used to store data for a longer duration. It uses memory known as “flash memory” which is like RAM, which clears the data each time the computer is turned off.
SSDs use a grid of electrical cells to send or receive data fast. Grids are divided into divisions called pages & these pages store data. The combination of Pages is called “blocks”,
wherein HDD comprises of a stack of magnetic plates with a reading needle. For needle you read and write data, the plates have to move and go to the right location.
Differences between SSD & HDD
SSDs can write to blank pages in a block only wherein the data on HDD can be stored to any place on the plate. In other words, it is easy to overwrite data on HDD but on SSD, data can’t be overwritten, you can write data to blank pages only located in a block.
That’s why, every time SSD finds that it has sufficient pages in a block which are not in use, SSD devotes the data to memory which is estimated to whole block space. It can either delete the whole block, then commits data again from memory back to the block, meanwhile keeping the pages not use blank.
This indicates that SSDs run slow with time, which is one of the downfalls. When you buy a new SSD, it works fast and performs operations at a very good speed as there are so many blank pages. Although, with time, when space is occupied by data and you are not left with any blank pages and all you have are some random unused pages dispersed all over the blocks.
When your SSDs reaches to this extent, whenever you need to write data, your SSDs needs to follow a certain procedure.
First, it must look for a block with sufficient unused pages. Then, it must know which pages in the block is useful. Next step would be to reset all the pages of the block to blank. Now, it will rewrite the useful pages in that block. The last step will be filling the rest of the pages with new data.
This is the process that your SSD will follow every time, when it has to write new data. Even though your SSD must go through this entire process, it is still faster than conventional HDD and the money spent over SSD is worth.
Everything has its pros and cons. SSD has it too. After understanding the whole mechanism of SSD, it is necessary to know the downfalls as well. As SSDs work on flash memory, it can only survive a certain number of write before it gives up.
When SSD is in use, electrical charges in each data cells should reset from time to time. However, the electrical resistance of each cell increases moderately with every reset, in turn, increases the voltage required to write into that cell. With time, the voltage of the specific cell increases so much that it’s not possible to write on to it. That’s why SSD’s data cells can only sustain a limited number of writes.
This is all you need to know on how SSD works!