Ball Grid Array
as i write in title
from my heart...as much i can.
why ?
I powered off my 56 TB netapp storage and when I power back on , 1 filler don't boot
reason - > nvram module bad ( 512 MB ECC , ?sram?>no specs on labels )
for sure, quick cold of memory make mechanical stress on balls and they detached

the company have 200 barcode readers. on all readers i resolder myself 48 bga, 1Mbit sram memory, on some devices twice or 3 times.
smart designers placed the memory under rubber scan key so the board bend and the memory detached.

we also can say "F#{% thank you" BGA designers and Pb free alloy stupid RoHS for eMMC BGA chip detached on any light drop of N900

nobody die from lead founded in electronics or several kg of car battery