Address Binding: a mapping from one address space to another

Binding of instructions and data to memory addresses can be done at ____________
a) Compile time
b) Load time
c) Execution time

If the process can be moved during its execution from one memory segment to another, then binding must be delayed until run time.

Dynamic loading: is loading a routine only when it is called

The advantage of dynamic loading is: An unused routine is never loaded

The idea of overlays is to ___________
a) data that are needed at any given time
b) enable a process to be larger than the amount of memory allocated to it
c) keep in memory only those instructions

The programmer must design and program the overlay structure.
The Memory manager swaps processes in and out of the memory.

If a higher priority process arrives and wants service, the memory manager can swap out the lower priority process to execute the higher priority process. When the higher priority process finishes, the lower priority process is swapped back in and continues execution. This variant of swapping is sometimes called?
Answer: roll out, roll in

If binding is done at assembly or load time, then the process can never be moved to different locations after being swapped out and in again.

In a system that does not support swapping the compiler normally binds symbolic addresses (variables) to relocatable addresses.

When overlays are used, the size of a process is not limited to the size of the physical memory

The address generated by the CPU is referred to as Logical address.

The address loaded into the memory address register of the memory is referred to as Physical address.

The run time mapping from virtual to physical addresses is done by a hardware device called the Memory management unit.

The base register is also known as the relocation register.

The size of a process is limited to the size of physical memory.

If execution time binding is being used, then a process may be swapped to a different memory space.

Swapping requires a backing store.

The backing store is generally a ______
a) fast disk
b) disk large enough to accommodate copies of all memory images for all users
c) disk to provide direct access to the memory images

The ready queue consists of all processes whose memory images are in the backing store or in memory and are ready to run.
The context – switch time in a swap out of a running process and swap in of a new process into the memory is very high.
The major part of swap time is transfer time.
Swapping must never be done when a process has pending I/O, or has to execute I/O operations only into operating system buffers.
Swap space is allocated as a chunk of disk.

Memory Management

CPU fetches the instruction from memory according to the value of program counter.

A memory buffer used to accommodate a speed differential is called cache.

Which one of the following is the address generated by CPU?
     --logical address

Run time mapping from virtual to physical address is done by Memory management unit.

Memory management technique in which system stores and retrieves data from secondary storage for use in main memory is called paging.

The address of a page table in memory is pointed by page table base register.

Program always deals with logical address.

The page table contains base address of each page in physical memory.

What is compaction?
     --a technique for overcoming external fragmentation

Operating System maintains the page table for each process.