What is the difference between automatic and dynamic allocation?


What is the difference between automatic and dynamic allocation?

Automatic storage uses memory very efficiently, but it's useless for objects with lifetimes that persist beyond function calls. By comparison, dynamic storage allocation is much slower than either static or automatic allocation.

Why is Relocation important in memory management?

When a program gets swapped out to a disk memory, then it is not always possible that when it is swapped back into main memory then it occupies the previous memory location, since the location may still be occupied by another process. We may need to relocate the process to a different area of memory.

What is PCB operating system?

A process control block (PCB) is a data structure used by computer operating systems to store all the information about a process. It is also known as a process descriptor. When a process is created (initialized or installed), the operating system creates a corresponding process control block.

What is demand paging OS?

In a system that uses demand paging, the operating system copies a disk page into physical memory only if an attempt is made to access it and that page is not already in memory (i.e., if a page fault occurs).

What is circular wait?

Circular wait: each process must be waiting for a resource which is being held by another process, which in turn is waiting for the first process to release the resource.

What is symbolic address?

Quick ReferenceAn addressing scheme whereby reference to an address is made by some convenient symbol that (preferably) has some relationship to the meaning of the data expected to be located at that address. It serves as an aid to the programmer.

What is dynamic relocation in operating system?

Dynamic relocation is where data currently stored in the computer memory is relocated to other parts of the computer. This process creates more efficient memory storage while a program is still active.

What is absolute and relocatable code?

Basically, "absolute" mode means that the code and RAM variables will be placed exactly where you tell the assembler it will be, while "relocatable" means the assembler builds code chunks and specifies RAM needs that can be placed wherever the linker finds room for them.

What is relocatable object code?

A relocatable file holds sections containing code and data. These files are suitable to be linked with other object files to create executable files, shared object files, or another relocatable object. An executable file holds a program that is ready to execute.

What is DB in assembly?

In assembly language, we use "db" (data byte) to allocate some space, and fill it with a string.

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