Question: WD’s page on NasWare 3.0 states the following:
NASware further improves drive reliability and protects your data in the event of a power loss or disruption.
Answer:Here is another one (6TB WD Re WD6001FSYZ-01SS7B1):
http://www.hddoracle.com/viewtopic.php?f=3&t=2762This “enterprise class” drive incorporates WD’s newer ARCH7 firmware architecture. Location U12 is occupied by the firmware as in earlier models, but there are an additional 6 x Winbond 8Mbit SPI flash memories at U15 – U20. These 6 “ROMs” were mostly empty when the owner dumped them. At the time we were all puzzled as to the function of these ROMs, but it now appears that they may be involved in power loss protection. In fact there is a bank of 11 capacitors nearby, and these appear to be charged via a diode in a boost converter configuration.
The datasheet confirms that Power Loss Data Protection is present in capacities of “5 TB and above”:
https://www.elfadistrelec.fi/Web/Downloads/-t/ds/WD-RE_SATA_2-6TB-eng-tds.pdf
Here is the PCB from the 4TB drive on the same datasheet (WD4000FYYZ):
It has a single ROM at U12 and no capacitor bank, ie there are no power loss protection components.