Aug 23, 2013

How does TRIM keep devices running faster?

I’ve read that the added support for TRIM should keep new Android 4.3 devices from slowing down over time. That’s great, but what does TRIM actually do?

I guess in a sense you could think of TRIM as to SSDs as defragmenting is to HDDs. It’s not the same process, obviously. This article explains it pretty well: http://arstechnica.com/information-technology/2012/06/inside-the-ssd-rev...

What is TRIM Support?

"One of these terms is "TRIM support." To understand what TRIM support is, you first need to understand how solid-state drives work. SSDs use NAND flash memory to store and transfer information. This flash memory is created up of small "pages" and groups of pages are called "blocks." When you tell your computer to delete a page on the solid-state drive the page isn't actually deleted - it is merely marked for deletion. This is because data can only be deleted in blocks. You cannot delete individual pages on an SSD. Later on, when you tell your computer that you need the space, the pages marked for deletion are grouped into a block and the whole block is wiped clean. This process slows down the solid-state drive when it is writing."
Ron Johnson

From Wikipedia:

"Because low-level operation of SSDs differs significantly from hard drives, the typical way in which operating systems handle operations like deletes and formats resulted in unanticipated progressive performance degradation of write operations on SSDs. TRIM enables the SSD to handle garbage collection overhead, which would otherwise significantly slow down future write operations to the involved blocks, in advance."


Not only must the SSD support for the TRIM command, but the OS must be programmed to issue the command at appropriate intervals.  Apparently, that support has finally been added to Android.

Answer this