Storage Allocation Strategies

Storage Allocation Strategies:

There are three different storage allocation strategies based on runtime storage. They are:

• Static Allocation
• Stack Allocation
• Heap Allocation

Static Allocation:

• Storage is allocated at compile time
• Static storage has fixed allocation that does not change during program execution
• As bindings do not change at runtime, no runtime support is required
• At compile time, compiler can fill the address at which the target code can find the data it operates on
• FORTRAN uses the static allocation strategy

Limitations

• Size of data objects should be known at compile time
• Recursion is not supported
• Data structures cannot be created at runtime

Stack Allocation

• Stack allocation manages the runtime storage as a stack, i.e., control stack
• Activation records are pushed and popped as activation begins and end respectively
• Locals are always bound to fresh storage in each activation, because a new activation is onto a stack when a call is made
• Values of locals are deleted as activation ends
• The data structure can be created dynamically for stack allocation

Limitations

• Values of locals cannot be retained once activation ends
• The memory addressing can be done using pointers and indexed registers
• This type of allocation is slower than static allocation

Heap allocation

• Storage can be allocated and deallocated in any order
• If the values of non-local variables must be retained even after the activation record then such a retaining is not possible by stack allocation
• It is used for retaining of local variables
• The heap allocation allocates the continuous block of memory when required for storage of activation records. This allocated memory can be deallocated when activation ends
• Free space can be further reused by heap manager
• It supports for recursion and data structures can be created at runtime

Limitation

• Heap manages overhead.

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About Data Sciences by Venu

Hi, My name is Venugopala Chary and I'm Currently working as Associate Professor in Reputed Engineerng College, Hyderabad. I have B.Tech and M.tech in regular from JNTU Hyderabad. I have 11 Years of Teaching Experience for both B.Tech and M.Tech Courses.