We don't want to allow special characters in the address. It really states which chars aren't allowed. The square brackets are required. The following string represents one word in the typical username. Basically, a word is either an atom or quoted string.
Some companies see storage area networks as a solution.
A SAN is a dedicated configuration of multiple servers connected to peripheral storage devices using high-speed fiber and special routers, switches and hubs. A SAN, usually part of an enterprise's overall computing resources, enables enterprises to consolidate data from disparate servers on to a centrally managed storage network. But the adoption rate of SANs has been slowed by drawbacks such as high cost, interoperability of software, hardware and components and data security concerns. The Pros Data Sharing. A SAN makes stored data available to multiple users simultaneously, without disrupting productivity.