AT&T 6300 Programmer's Manual page 68

Variable Types
MEMORY REQUIREMENTS
The number of bytes required by strings,
variables and arrays is listed below.
Variable Type
Integer
Single Precision
Double Precision
Array Type
Integer
Single Precision
Double Precision
Bytes
2
4
8
Bytes
2 per
element
4 per
element
8 per
element
3-10
Strings
3 bytes overhead plus the present contents of the string.