Why don't SSDs wipe when you shut down the PC?

[nathan4102]

I understand that flash memory works 100% electronically, and if power is lost data is lost as well. I know this is true with RAM. HOWEVER SSDs and USB flash drives don't erase when you disconnect them or unpower them. Why does this happen?

Just kind of curious 😛

Thanks!

 

[tsuneo6]

short answer, RAM is volatile memory, ssd's exist of non volatile memory
do you also want "scientific explenations'
SSD's dont have "RAM memory" inside. it's another technology. they use floating gate transistors.

 

[tsuneo6]

http://www.cse.scu.edu/~tschwarz/coen180/LN/flash.html hee you can read how that works

 

[clutchc]

Because they use EEPROMs*. They have to be electrically erased.
Who told you that flash memory looses its data when power is removed?

*Electrically Erasable Programmable Read Only Memory.

 

[nathan4102]

Thanks you two, I'll look into the link! I suppose I've always grouped SSDs, USBs, and RAM as "Flash" and me hearing that RAM wipes when you remove power lead me to think that all Flash devices do the same... I starting thinking Flash drives had small batteries keeping the circuits powered 😀

 

[tsuneo6]

SSD's do have a small battery, but that is for the cache memory. when your PC loses power, the SSD will remember the data in the cache memory.

 

[tsuneo6]

so that's pretty much a little bit of RAM in your ssd! but that's not the "big storage place"