Host Computers
A host computer processes, produces, and stores all the information for mobile commerce applications. Most of the mobile commerce application programs reside in this component, except for some client-side programs such as cookies. This component contains three major components: a Web server, a database server, and application programs and support software.
Web Servers
A Web server is a server-side application program that runs on a host computer and manages the Web pages stored on the Web site's database. There are many Web server software applications, including public domain software from NCSA and Apache, and commercial packages from Microsoft, Netscape, and others. Among them, Apache has been the most popular HTTP server on the Internet. It features highly configurable error messages, DBM-based authentication databases, and content negotiation.
Database Servers
A database server manages database access functions, such as locating the actual record being requested or updating the data in databases. Other than the server-side database servers, a growing trend is to provide a mobile database or an embedded database to a handheld device with a wide range of data-processing functionality. Embedded databases have very small footprints, and must be able to run without the services of a database administrator and accommodate the low-bandwidth constraints of a wireless-handheld network.
Application Programs and Support Software
Web and database servers are mandatory for mobile commerce systems; application programs handle all server-side processing. However, to facilitate mobile commerce applications, some other support software is needed. For example, various programming languages, including Perl, Java, Visual Basic, C/C++, etc., and the CGI for transferring information between Web interfaces and CGI scripts are necessary.