Information Technology Reference
In-Depth Information
Markers
String
Enumerations
Records
Array
Boolean
Primitive Data Type
Character
Integer
Custom
Real Floating Point
Fig. 7.4
The primitive data types
Character, String, Boolean, Real Floating Point, Enumeration, Marker, Record or
Custom). These will each be described in more detail below.
One other important organisational view of data is viewing the data as sequences
of octets (eight bit bytes - bytes have varied in bit size through the history of com-
puting but currently eight bits is the norm). Typically PDTs are composed of one or
more octets and the order in which the octets are read is important. This ordering
of the octets is usually called byte-order and is a fundamental property of the PDT.
There are two types of byte-order in common use (although others types do exist),
big-endian and little-endian. Figure
7.5
shows a PDT instances that has four octets.
Fig. 7.5
Octet (byte) ordering and swapping
