Microsoft KB Archive/103878
Article ID: 103878
Article Last Modified on 7/30/2001
This article was previously published under Q103878
Network I/O Redirection
When a device identifier (for example: f:, p:, lpt1:) is redirected to a remote resource in a network command such as
NET USE F: \\SERVER\SHARENAME
the network software that carries out the redirection sets flags in the operating system's internal device table indicating that the device is remote. File handles for files that are subsequently created or opened on these remote devices are likewise flagged as remote.
When the operating system receives an I/O request--by way of an MS-DOS interrupt x21 or OS/2 API call--directed to a remote device or file, it passes the request to the network redirector instead of calling a local device driver. The redirector formats the I/O request so that it can be understood by the owner of the remote device, the server, and sends it on its way through the network.
The network services provided by the operating system and the redirector generally map to the OSI application layer.