LOCIS (Library of Congress Information System) is the Library's original retrieval system that runs on a mainframe computer. LOCIS provides access to all of the catalog files that are created and maintained by the Library and provides access to a variety of other files. LOCIS also provides the widest variety of search features. LOCIS is a command-driven system requiring a user to type in commands for searching and displaying search results.
Several files contain records for materials cataloged and held by the Library of Congress. In addition, there are some records for materials cataloged and held by other research institutions or agencies. Together, the materials include a variety of formats. The Library catalogs materials in over 400 languages. The materials are:
LOCIS provides access to an alphabetical index for browsing and to key word searching. Browsing is available on all the non-catalog files and some of the catalog files (books, microforms, serials, cartographic materials, the PreMARC file with early materials, and the file of subject cross references). Key word searching is available for all the catalog files and for the files of federal legislation.
With LOCIS, search results may be stored in sets for further manipulation, including a host of options for limiting search results based on various features (such as types of illustrations, date legislation is introduced).
All files have extensive help screens.
LOCIS is available over the Internet through the TELNET functions (telnet and tn3270) of the Internet's set of protocols known as TCP/IP. At this time this is the only way to connect to LOCIS, which was developed many years ago for a mainframe computer environment.
Since LOCIS was developed as an IBM mainframe system, it is best to connect to LOCIS with the tn3270 method.
Please note that most library online catalogs available over the Internet also were initially available only through this Internet method. In recent years library catalogs have been experimenting with other access methods, such as using WWW fill-in forms, and the Library of Congress has been experimenting with these as well.
The telnet and tn3270 software typically come with the products that enable your workstation to connect the Internet; or, your Internet Service Provider (ISP) provides this function for you. Even though you may have this software, it is important that it be configured properly on your workstation.
In many instances, WWW and Gopher sites include links to online library catalogs. However, for these links to be successful, the WWW browser software and the Gopher software also must be able to find and invoke the telnet or tn3270 capabilities. In cases where an "error" message states that an application cannot be found, this usually means that the telnet or tn3270 capabilities either are not present or cannot be found on your workstation. Consult your browser or Gopher manual or your Internet Service Provider for assistance.
You may connect to LOCIS through the Library of Congress WWW site or Gopher site (LC MARVEL). However, either telnet or tn3270 must be available in some manner on your workstation or be available through your ISP.