2. Run-time environments
Two themes
The allocation of storage locations
Static allocation
Stack allocation
Heap management
Garbage collection
Access to variables and data

3. Storage Organization code static Heap Free memory stack
Static---complile time
Dynamic---run time
Figure 7.1 Typical subdivision of runtime memory into code and data areas

4. Storage Organization Static Code
The size of the generated target code is fixed at the compile time
Static
Some program data objects, such as global constants ,nonlocal names
one reason for statically allocating as many data objects as possible is that the address of these objects can be compiled into the target code.

5. Storage Organization Dynamic area
Size can change as the program executes
To maximized the utilization of space at run time , Stack and Heap are at the opposite ends of the remainder of the address space.
Stack is used to store data structures called activation records that get generated during procedure calls
Heap is used to manage long lived data ,such as pointers in C and Objects in C++

6. Storage allocation strategy
Static allocation lays out storage for all data objects at compile time
Stack allocation manages the run-time storage as a stack
Heap allocation allocates and deallocates storage as needed at run time from a data area known as a heap