machine on the network can authenticate its users, gain access to resources, and then call them remotely using a single integrated API. The rise of the Internet, Java and web services stole much of DCE's mindshare through the mid-to-late 1990s, and competing systems such as CORBA muddied the waters as well. One of the major uses of DCE today is Microsoft's DCOM and ODBC systems, which use DCE/RPC (in MSRPC) as their network transport layer. OSF and its projects eventually became part of The Open Group, which released DCE 1.2.2 under a free software license (the LGPL) on 12 January 2005. DCE 1.1 was available much earlier under the OSF BSD license, and resulted in FreeDCE being available since 2000. FreeDCE contains an implementation of DCOM. One of the major implementations of DCE was Encina, originally developed by Transarc (who were acquired by IBM). IBM used Encina as a foundation to port its primary mainframe transaction processing system (CICS) to non-mainframe platforms, as IBM TXSeries. (However, later versions of TXSeries have removed the Encina component.) Architecture The largest unit of management in DCE is a cell. The highest privileges within a cell are assigned to a role called cell administrator, normally assigned to the "user" cell_admin. Note that this need not be a real OS-level user. The cell_admin has all privileges over all DCE resources within the cell. Privileges can be awarded to or removed from the following categories : user_obj, group_obj, other_obj, any_other for any given DCE resource. The first three correspond to the owner, group member, and any other DCE principal respectively. The last group contains any non-DCE principal. Multiple cells can be configured to communicate and share resources with each other. All principals from external cells are treated as "foreign" users and privileges can be awarded or removed accordingly. In addition to this, specific users or groups can be assigned privileges on any DCE resource, something which is not possible with the traditional UNIX filesystem, which lacks ACL's. Major components of DCE within every cell are: The Security Server that is responsible for authentication The Cell Directory Server (CDS) that is the repository of resources and ACLs and The Distributed Time Server that provides an accurate clock for proper functioning of the entire cell Modern DCE implementations such as IBM's are fully capable of interoperating with Kerberos as the security server, LDAP for the CDS and the