A given implementation of the TuringMachine abstraction must define certain architectural elements for sake of practicality.  Some of those elements are things like word size (i.e. register size), stack-size, floating point, etc.  

These choices will affect the ''types'' that the system makes available, and in practice how higher-level programming languages will define themselves and interface to the machine.  

''Architectural elements can be ignored by higher-level programming languages.  That's part of what makes them higher-level.  It is perfectly reasonable for a higher-level language to provide, say, a built-in integer type that is not a reflection of the underlying hardware, e.g., infinite precision.''

See also ObjectArchitecture.

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