A character string is a contiguous sequence of bytes in memory, as shown below.
CHARACTER Data Representation
A character string is specified by two attributes: the address A of the first byte of the string, and the length L of the string in bytes.
On Windows* systems, the length L of a string is in the range 1 through 2,147,483,647 (2**31-1) .
On Linux* systems, the length L of a string is in the range 1 through 2,147,483,647 (2**31-1) for systems based on IA-32 architecture and in the range 1 through 9,223,372,036,854,775,807 (2**63-1) for systems based on Intel® 64 architecture.