why is SAN drive recognized as local drive while NAS isn't?

Hi all;

Maybe this's just a simple question for experts in storage sharing.
Why are SAN drives recognized as local drive while NAS drives aren't?
I knew that SAN uses block level transfer to transfer data while NAS uses file level transfer. Does this has anything to do with why SAN drives and NAS drives are recognized differently by the computer? If yes, how?

Thank you.

You are on the right path - a SAN allows you to move the block level device outside the computer but still uses the underlying SCSI commands to talk to the device; a NAS device has a file system already laid on top of the drive and the NAS system is what uses SCSI to talk to the drive, your computer is simply mounting this device and is using CIFS to access the data.

Hope this helps.

Thank you.
Your reply is helpful.