When running Microsoft® SQL Server™ without a network, you do not need to start the built-in MSSQLServer service. Because SQL Server Enterprise Manager, SQL Server Service Manager, and the net start and net stop commands are always functional (even without a network), the procedures for starting and stopping SQL Server are identical for a network or stand-alone operation.
When connecting to a stand-alone SQL Server from a local client such as osql, you bypass the network and connect directly to the SQL Server using a local pipe. The difference between a local pipe and a network pipe is whether you are using a network. Both local and network pipes establish a connection with SQL Server using the standard pipe (\pipe\sql\query), unless otherwise directed.
When you connect to a local SQL Server without specifying a server name, you are using a local pipe. When you connect to a local SQL Server and explicitly specify a server name, you are using either a network pipe or another network IPC mechanism such as IPX/SPX (if you have configured SQL Server to use multiple networks). Because a stand-alone SQL Server does not support network pipes, you must omit the unnecessary /Sserver_name argument when connecting to the SQL Server from a client. For example, to connect to a stand-alone SQL Server from osql, type:
osql /Usa /P