$Linked (Built-in Mathematica Symbol)

$Linked is True if the Mathematica kernel is being run through MathLink.

$MachineAddresses (Built-in Mathematica Symbol)

$MachineAddresses gives a list of strings specifying the current IP addresses associated with the computer on which Mathematica is being run.

$MachineDomains (Built-in Mathematica Symbol)

$MachineDomains is a list of strings giving the names of the current network domains associated with the computer on which Mathematica is being run.

$MachineEpsilon (Built-in Mathematica Symbol)

$MachineEpsilon gives the difference between 1.0 and the next-nearest number representable as a machine-precision number.

$MachineID (Built-in Mathematica Symbol)

$MachineID is a string that gives, if possible, a unique identification code for the computer on which Mathematica is being run.

$MachineName (Built-in Mathematica Symbol)

$MachineName is a string that gives the assigned name of the computer on which Mathematica is being run, if such a name is defined.

$MachinePrecision (Built-in Mathematica Symbol)

$MachinePrecision gives the number of decimal digits of precision used for machine-precision numbers.

$MachineType (Built-in Mathematica Symbol)

$MachineType is a string giving the general type of computer on which Mathematica is being run.

$MaxExtraPrecision (Built-in Mathematica Symbol)

$MaxExtraPrecision gives the maximum number of extra digits of precision to be used in functions such as N.

$MaxMachineNumber (Built-in Mathematica Symbol)

$MaxMachineNumber is the largest machine-precision number that can be used on a particular computer system.