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Remote Library Services (RLS)

Introduction to Remote Library Services


RLS: Definition

Remote Library Services (RLS) enables you to read, write, and update remote data as if it were stored on the client's disk. RLS can be used to access SAS data sets across computers that have different architectures. RLS also provides read-only access to some SAS catalog entry types across computers that have different architectures.

With RLS, you use a LIBNAME statement to associate a SAS library reference (libref) with a SAS library on the server.


Client Access to a Single- or Multi-User Server

To access a SAS library on a server that you are already signed on to (using the SIGNON statement), a single-user server environment is assumed. To identify the server, specify the remote session ID that was used at sign on. For details about the SIGNON statement, see SIGNON Statement and Command.

To access a server that you are not signed on to, a multi-user environment is assumed. When you connect to a multi-user server, the server must already be running. Use the SERVER= option in the LIBNAME statement to specify the server ID.

Therefore, to connect to both a single-user server and a multi-user server from your client session, and to avoid confusion, assign unique values to the SERVER= option. The use of the single-user server takes precedence over the multi-user server.

After you define a libref to a server, avoid clearing and re-assigning the libref multiple times. Repeating this sequence is inefficient because the client session disconnects from the server after the last libref that is associated with a server is cleared. When the same libref is re-issued, the client session must connect to the server again. To avoid this overhead, clear the defined librefs only after you have completed any processing that accesses data that is defined by these librefs.

A server does not automatically terminate after the last LIBNAME statement is cleared. A multi-user server remains active, awaiting connections from clients until the server administrator explicitly stops the server by using the PROC OPERATE statement. For details, see the OPERATE procedure in the SAS/SHARE User's Guide.

A single-user server remains active, awaiting connections from a client session until the client uses the SIGNOFF command to terminate the server session. For details, see SIGNON Statement and Command.

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