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I. Outline and Objective This article is to understand what LDAP is a foundation. The goal is to make you master the basic terms and concepts, not to learn about LDAP. LDAP, its full name is a lightweight directory access protocol. This article includes the following aspects: * Basic definition of the directory * What can I do and what I can't do * 2 directory example * Summary Use the catalog of directory services II, the basic definition directory is a dedicated database, It serves a variety of applications, including the LDAP (Lightweight Directory Access Protocol) directory and the X.500-based directory. These catalogs are generally standard catalogs. They are not suitable for specific operating systems, application purposes. No matter what they don't know what the catalog here, most people are familiar with a variety of catalogs, like phone books, yellow pages, television guides, shopping catalogs and library card catalogs. We use this type of directory as a daily directory. The directory in the computer is called an online directory. Directory services are software, hardware, policy, and managed aggregates. The directory service includes at least a few aspects: * Includes information in the directory * Software server server with the saving information * Play Access information software client * running server, client software hardware * Support system, like operating system, Device Driver, etc. * Connect the client to the server and the network infrastructure * policy between each server. Specify who can access, who can update, who can access * Software terms and directory services for maintenance and monitoring directory services often exchange. Third, the directory is what the application type below does not be classified as a directory: * Database * File system * Web service * FTP service * DNS service and database comparison Although the directory is also known as a special database, but it is different The real database. Most of the catalog operations are read operations. If your application wants to write a lot of data, you should consider choosing to use the database to implement. The directory supports relatively simple transaction processing. Instead, the database is designed to handle a wide variety of transaction processing. If your application requires this heavy-duty transaction support, you should choose the database instead of the directory. On the other hand, if your application does not require such large load transaction, it is occasionally written some simple transaction information. At this time, the directory is ideal. It will be more effective and simpler. The comparison directory with the file system is considered a poor file system. The file is usually large, there are several megabytes, although the directory is optimized to access small information. Applications access files in a block. File systems support various calls - like seek (), read () and write (), which can write some of the information of a large file. This is not available to this random access. The catalog entry is divided into various properties. You can get a variety of properties separately. You can't get part of an entry, as starting from the first few bytes. Compare with the Web is not like a web server, the directory is not suitable for pushing the JPEG image or the Java program to the client. Web services typically use springboards for development web applications. These platforms from CGI (public gateway interface) to more complex Like Netscape Application Service Platform. Directory generally does not provide this form of application development, and even does not provide a directory application development platform service. The main difference from FTP compare with FTP is that the amount of data and the type of customer. Another point is that FTP is a very simple agreement that is dedicated to do one thing and do it well. If you want to do it, send files from one place to another, then additional directory is also required, such as copy, query, update, etc. The domain name system and directory of the Internet are similar to DNS, they all provide access to layered databases. But there are some different points to distinguish them. The main purpose of DNS is to convert host names into IP addresses. In contrast, most directories have a more common role. DNS has a special, fixed plan, while the directory is allowed to be expanded. DNS is not allowed to update its information, and the directory can. DNS can be accessed through the UDP's unconnected manner, and the directory is usually connected. Fourth, the directory example X.500 In the middle of the 1980s, two different groups - CTTT and ISO were beginning to research in directory services.
