This is not a thread about what is better (Storage Area Netowrk devices or Network Attached Storage); this is a thread about what the definition of a NAS device is and, accordingly, what the definition of a SAN device is (that is, the devices which provide the storage, i.e., host the disks).
I believe that a NAS device is a device which presents storage on the network that can be written to at the "file level" without worrying about lower levels of the details of the write (e.g., the file system format, drive internals). NAS therefore (under my definition) would use file-based protocols such as SMB.
I believe a SAN device is a device that presents a disk-block level of storage on the network that requires an integral (e.g., you typically must install additional software on the client machine (that is, the client machine with the disk hosting machine being the server) in order to write to the SAN device).
I believe that both a SAN device and a NAS device could be connected to a network with only "client" machines (say, machines running XP). I believe that, in fact, the presence or absence of a server on a network does not change the type of a given device (be it SAN or NAS) to the other.
I believe that a device is either a SAN or a NAS, but cannot be both at the same time (except in some bizarre situation where one server is presenting both types of protocols). This is to say, if I buy a SAN device, it should NOT be called a NAS device because I cannot access it (from any computer, not just a server) with a file-level operation.
Which of my beliefs are wrong and why?
