Understanding and Deploying LDAP Directory Services > 2. A Brief History of Directories > Application-Specific and Special-Purpose Directories |
Application-Specific and Special-Purpose DirectoriesIn this section we discuss directories that are tied to a specific application (or to a tightly integrated suite of applications). These directories are distinguished from other, more general-purpose directories (such as LDAP directories) by their tight integration with specific applications and their use of proprietary interfaces and protocols. Typically, it is difficult or impossible to use these directories with directory-enabled applications they were not designed to support. Application-Specific DirectoriesIn the early 1990s, application-specific directories entered the mainstream (although they existed in various forms for many years before then). Application-specific directories are typically embedded in electronic mail and groupware products and are intended to serve the needs of only one application or a small suite of applications. The design of these directories is often driven by the user interface requirements of email or groupware applications. Examples of these directories include the following:
Most of these application-specific directories are still sold and used today. Over time, they have become somewhat less proprietary in that most of them now provide LDAP client access. Typically, the LDAP support is second-rate and accomplished through gateways that are retrofitted to the existing service. By their very nature, application-specific directories tend to be hard to extend for use by other directory-enabled applications. Centralized Internet DirectoriesA second category of special-purpose directories has recently emerged since the explosion of Internet content services: large, centralized directories that hold information about Internet users. Some of the best known directories are
These directories often acquire this information about users from a combination of Usenet News postings and voluntary registration. Typically, the centralized Internet directory services also provide a directory based on public telephone directory information and are quite popular with users who are looking for lost loves or their old high school buddies . Now that Internet email clients and Web browsers can act as LDAP clients , many of these directories support access over LDAP in addition to their primary HTML form-based interfaces. Like most Internet content providers today, they fund their services through the sale of advertisements that appear at the service access points or within search results.
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Index terms contained in this sectionapplication-specific directories 2ndcentralized Internet directories 2nd directories history of application-specific directories 2nd centralized Internet directories 2nd history of directories application-specific directories 2nd centralized Internet directories 2nd |
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