Although you can run the database server like any other Windows program rather than as a service, there are limitations to running it as a standard program, particularly in multi-user environments.
When you start a program, it runs under your Windows login session, which means that if you log off the computer, the program terminates. This restricts the use of the computer if you want to keep a program running most of the time, as is commonly the case with database servers. You must stay logged on to the computer running the database server for the database server to keep running. This can also present a security risk as the Windows computer must be left in a logged on state.
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 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.
Sybase Central provides a more convenient and comprehensive way of managing SQL Anywhere services than the Windows services manager. You can also use the dbsvc utility to create and modify services. See Service utility (dbsvc) for Windows.