$BatchOutput is True if output in the current session is being sent in batch mode, suitable for reading by other programs.
$FrontEnd is a global variable that specifies to what front end object, if any, the kernel is currently connected.
$FrontEndSession is a global symbol that represents the current session of the front end from which the kernel is being run.
$MinNumber gives the minimum positive arbitrary-precision number that can be represented on a particular computer system.
When Mathematica cannot give you an explicit result for an integral, it leaves the integral in a symbolic form. It is often useful to manipulate this symbolic form. ...
$CUDALinkPath is the path to the CUDALink application.
OpenSQLConnection[src] makes a connection to a data source.OpenSQLConnection[] opens a GUI that helps to make a connection to a data source.
SQLServer[...] is an object that represents a server process started in Mathematica.
$DatabaseLinkDirectory gives the directory where DatabaseLink is installed.
SetPeriodicalInterval[id, interval] resets the time interval for the periodical task with the given id.