SAN Vs NAS

Good Article on SAN Vs NAS

http://www.nas-san.com/differ.html

A SAN commonly used Fibre Channel

Any computer that connects to LAN act as NAS using NFS or CIFS

NAS uses TCP/IP and NFS/CIFS/HTTP protcols

SAN uses Encapsulated SCSI protcol

The basic diffence b/w SAN, NAS is
"The kind of I/O Operation ? if it is an Block I/O then it is SAN,
if it is an File I/O then it is an NAS"