ASA Database Administration Guide
  Running the Database Server
    Running the server outside the current session

Understanding Windows services

Although you can run the database server like any other Windows NT/2000/XP program rather than as a service, there are limitations to running it as a standard program, particularly in multi-user environments.

Limitations of running as a standard executable 

When you start a program, it runs under your Windows NT/2000/XP login session, which means that if you log off the computer, the program terminates. Only one person logs onto Windows NT/2000/XP (on any one computer) at one time. This restricts the use of the computer if you wish to keep a program running much of the time, as is commonly the case with database servers. You must stay logged onto the computer running the database server for the database server to keep running. This can also present a security risk as the Windows NT/2000/XP computer must be left in a logged on state.

Advantages of services 

Installing an application as a Windows  service enables it to run even when you log off.

When you start a service, it logs on using a special system account called LocalSystem (or using another account that you specify). Since the service is not tied to the user ID of the person starting it, the service remains open even when the person who started it logs off. You can also configure a service to start automatically when the Windows computer starts, before a user logs on.

Managing services 

Sybase Central provides a more convenient and comprehensive way of managing Adaptive Server Anywhere services than the Windows services manager.