3) Memory Management Flashcards
What does Memory Management primarily deal with?
It deals with main memory and its relationship to secondary storage.
What is Memory
Memory is seen as a linear array of addressable locations.
Main memory is a random access memory. Define random access.
All of its locations are equally accessible
What is Memory Management? (MM)
MM is the task of storing and managing multiple processes in the main memory, with the help of the OS and the hardware.
Define Relocation.
Relocation is the idea of converting a logical address into a physical address.
what “Protection Protocol” must memories follow?
Processes must not reference a memory location that is already assigned to another process without permission.
Sometimes, areas of memory must be shared by multiple processes. Give 2 reasons of when this is the case.
- Several processes are executing the same program.
- Cooperating processes.
While the MM is a linear address space, programs are often organised in a hierarchical manner. State how they are sorted.
- Based on different types of programs (read-write, read-only, execute only, private, shareable).
Primary memory is ____________ (fast/slow) but _____________ (cheap/expensive).
Secondary memory is ______________ (fast/slow) but _______________ (cheap/expensive).
Primary memory is fast (fast/slow) but expensive (cheap/expensive).
Secondary memory is slow (faster/slower) but cheap (cheap/expensive).
What is “Memory Overlaying”?
This is when programs or section of programs are sent to the main memory, overwriting existing programs.
(Note: This places a heavy burden on the programmer, because it is difficult to debug an can cause ‘disk trashing’).
What is a partition?
A partition is a set of contiguous locations which holds a process. There are dynamic and fixed partitions.
What is fragmentation?
This is the phenomenon of when free storage space is divided into 2 non-contiguous storage spaces.
Define a relative address.
A relative address is similar to a logical address of which points to a certain point of the program
What is “Address Translation”?
This is the process of which the forming the physical address from the logical address.
Define Internal and External Fragmentation.
Internal Process - This is when a process is assigned to memory, leaving access memory. Because the memory space was larger than the process itself.
External Process - This is when a process is a assigned to a non-contiguous memory, making it difficult for the process to be stored there.
