16 Questions
What is the primary function of a Memory Manager?
To manage the main memory (RAM) of the system
What is the purpose of memory addressing?
To enable the CPU to access memory locations
What is the limitation of a 32-bit CPU in terms of memory addressing?
It can only support up to 4 GB of memory
What is the purpose of deallocating memory?
To free up memory when it is no longer needed
What is the term for the linear sequence of bytes in a system's RAM?
Linear store
What is stored in CPU registers during process execution?
Memory addresses
What is the purpose of the Memory Manager's validation of memory requests?
To check the validity of each request for memory space
What is the term for the process of swapping pages of memory to and from disk storage?
Page swapping
What is the process image in the context of process memory allocation?
The combined memory footprint of a process
What happens to jumps to labels during the loading of a process image?
They are replaced by real memory addresses
In what direction does the stack grow in a process's address space?
Downwards from the top of the process address space
What is the purpose of the heap area in a process's memory allocation?
To provide memory for the programmer to reserve
What is the main disadvantage of compile-time address binding?
It prevents the OS from moving the program to another memory location
What is the main advantage of load-time address binding?
It provides more efficient use of memory by the OS
What happens to the jump location (start label) during compile-time address binding?
It is turned into a fixed memory address
What type of address binding allows a program to be loaded anywhere in memory?
Load-time address binding
Study Notes
Memory Management
- The memory manager manages the main memory (RAM) of the system, ensuring each process gets the memory it needs.
- It preserves and protects the space in memory occupied by the OS itself.
- It checks the validity of each request for memory space, allocates free areas of memory for valid requests, and deallocates memory when no longer needed.
Memory Addressing
- Memory inside a system (RAM) can be viewed as a linear sequence of bytes, also known as the linear store or flat model.
- Addresses range from zero up to the number of bytes available, and memory is byte addressable.
- Addresses are stored in CPU registers during process execution, limiting the address space by the bit length of the CPU.
- A 32-bit CPU can address 4,294,967,296 individual bytes, supporting up to 4 GB of memory.
Process Memory
- A program exists on disk as a binary executable file, storing program instructions as a sequence of bytes.
- When a program is run, the binary image is loaded into main memory, reserving extra memory for variables and the stack.
- The combined memory footprint is the process image, with the instruction pointer set to the first byte of the image.
- Jumps are replaced by real memory addresses, pointing to a physical location within the process image.
Stack and Heap
- The stack grows downwards from the top of the process address space, while the process instructions start at the bottom of the image.
- The memory footprint of a process includes the data area (memory for variables and objects) and the heap (memory available for programmer reservation).
Compile-Time and Load-Time Address Binding
- Compile-time address binding turns loops and jump locations into fixed memory addresses during compilation, assuming a program will always occupy the same area of memory.
- Load-time address binding turns loops and jump locations into relative addresses during compilation, allowing a program to be loaded anywhere in memory.
- Load-time binding offers advantages to the memory manager, allowing processes to be loaded anywhere in memory.
Learn about the role of a memory manager in operating systems, including managing RAM, allocating memory, and deallocating memory when no longer needed.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
