what is the purpose of a program segment
The size of this segment is determined by the size of the values in the program's source code, and does not change at run time. The data segment is read-write, since the values of variables can be altered at run time.he .data segment contains any global or static variables which have a pre-defined value and can be modified. That is any variables that are not defined within a function (and thus can be accessed from anywhere) or are defined in a function but are defined as static so they retain their value across subsequent calls.