Storage Solutions Please explain TRIM.

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Adept
Hello,
Yet another doubt which I can't seem to understand just by reading Wiki. What exactly is TRIM . All I understood until now is that it makes the SSD's live longer . And why are SSD so weak when it comes to Write,defrag ? Read these some where that you need to reduce the write cycles as much as possible when it comes to SSD's ?

Please it would be great if you could explain TRIM in laments term.Thanks a lot.
 
Here goes nothing mate..take what u can.

In traditional HDDs, when u delete a file ur OS simply flags the file as 'not in use', but in reality the HDD is waiting for something to be written over it thus replacing the already existing data, hence "deleting" it.

But in SSDs if data has to be written it can only be done in "empty" space, with me till now?. So without TRIM when u delete a file ur OS will simply flag it as "not in use" and when u try to write something there the SSD has to first delete it and then overwrite with new data. Same as HDDs right? well... now its gets a little complex and technical.

In SSD, u have "Pages(4KB)" which grouped into "Block(512KB)", the problem is u cannot erase a "Single Page" in an SSD, u have to erase an entire block, so when data in a page is set to delete and is about to be overwritten, the entire "Block" is copied to a cache (temp memory) and the necessary changes are made to the block and the data from the cache is pasted back. Now imagine this happening every time u write something to your SSD, it just makes the SSD work three times more than it should and thus degrading the life of it.

What TRIM does is, it tells the OS to inform the SSD which Blocks are not in use and can be deleted (without overwriting), so that the SSD can wipe it internally, and not have to wait for the Overwrite to happen. And thus reducing the TAX on the SSD increasing the life of it.

In a nutshell, TRIM actually allows the SSD to perform a real 'Delete' operation instead of "flag-it-now-and-wait-for-overwrite".

P.S i could've gone simpler but would not explain what is what.
 
Awesome!!! Thanks you made it very simple and easy to understand..

So is the TRIM available with the OS or the SSD?
 
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