PPT: Memory Management

 Page 1


Memory 
Management
Page 2


Memory 
Management
I n t r o d u c t i o n
Memory management is the 
process of controlling and 
coordinating computer memory, 
allocating it to processes, and 
ensuring efficient utilization. 
It serves as the backbone of 
modern operating systems, 
enabling multiple processes to 
run concurrently while 
maintaining system stability.
The key functions of memory 
management include allocation 
of memory to processes, 
deallocation when processes 
terminate, protection against 
unauthorized access, and 
controlled sharing among 
processes. 
These functions work together to 
overcome challenges such as 
limited memory size, concurrent 
access requirements, and the 
need for efficient utilization and 
speed.
Page 3


Memory 
Management
I n t r o d u c t i o n
Memory management is the 
process of controlling and 
coordinating computer memory, 
allocating it to processes, and 
ensuring efficient utilization. 
It serves as the backbone of 
modern operating systems, 
enabling multiple processes to 
run concurrently while 
maintaining system stability.
The key functions of memory 
management include allocation 
of memory to processes, 
deallocation when processes 
terminate, protection against 
unauthorized access, and 
controlled sharing among 
processes. 
These functions work together to 
overcome challenges such as 
limited memory size, concurrent 
access requirements, and the 
need for efficient utilization and 
speed.
Memory Hierarchy
1
Registers
Fastest, smallest memory located inside the CPU (typically 32-64 bytes). Provides immediate 
access to data being processed.
2
Cache
Fast, small memory close to CPU (KB-MB). Stores frequently accessed data to reduce 
CPU waiting time.
3
Main Memory (RAM)
Moderate speed, larger capacity (GB). Primary working memory for running 
applications.
4
Secondary Storage
Slow, large, persistent storage (HDD/SSD, TB). Retains data when 
power is off.
The memory hierarchy balances speed and cost while providing fast access to frequently used data. Data moves between levels based on usage 
patterns through processes like caching and swapping, optimizing overall system performance.
Page 4


Memory 
Management
I n t r o d u c t i o n
Memory management is the 
process of controlling and 
coordinating computer memory, 
allocating it to processes, and 
ensuring efficient utilization. 
It serves as the backbone of 
modern operating systems, 
enabling multiple processes to 
run concurrently while 
maintaining system stability.
The key functions of memory 
management include allocation 
of memory to processes, 
deallocation when processes 
terminate, protection against 
unauthorized access, and 
controlled sharing among 
processes. 
These functions work together to 
overcome challenges such as 
limited memory size, concurrent 
access requirements, and the 
need for efficient utilization and 
speed.
Memory Hierarchy
1
Registers
Fastest, smallest memory located inside the CPU (typically 32-64 bytes). Provides immediate 
access to data being processed.
2
Cache
Fast, small memory close to CPU (KB-MB). Stores frequently accessed data to reduce 
CPU waiting time.
3
Main Memory (RAM)
Moderate speed, larger capacity (GB). Primary working memory for running 
applications.
4
Secondary Storage
Slow, large, persistent storage (HDD/SSD, TB). Retains data when 
power is off.
The memory hierarchy balances speed and cost while providing fast access to frequently used data. Data moves between levels based on usage 
patterns through processes like caching and swapping, optimizing overall system performance.
Types of Memory Allocation
Contiguous Allocation
Process occupies a single contiguous block of memory. 
This approach includes fixed partitioning, where memory is 
divided into predetermined blocks, and dynamic 
partitioning, where memory is allocated based on process 
needs.
Non-Contiguous Allocation
Process memory is spread across non-adjacent locations. 
This includes techniques like paging and segmentation, 
which allow more flexible memory utilization.
Memory allocation strategies aim to minimize fragmentation and optimize memory usage. Internal fragmentation occurs 
when there is wasted space within allocated memory (common in fixed partitions), while external fragmentation refers to 
wasted space between allocated blocks (typical in dynamic partitioning).
Page 5


Memory 
Management
I n t r o d u c t i o n
Memory management is the 
process of controlling and 
coordinating computer memory, 
allocating it to processes, and 
ensuring efficient utilization. 
It serves as the backbone of 
modern operating systems, 
enabling multiple processes to 
run concurrently while 
maintaining system stability.
The key functions of memory 
management include allocation 
of memory to processes, 
deallocation when processes 
terminate, protection against 
unauthorized access, and 
controlled sharing among 
processes. 
These functions work together to 
overcome challenges such as 
limited memory size, concurrent 
access requirements, and the 
need for efficient utilization and 
speed.
Memory Hierarchy
1
Registers
Fastest, smallest memory located inside the CPU (typically 32-64 bytes). Provides immediate 
access to data being processed.
2
Cache
Fast, small memory close to CPU (KB-MB). Stores frequently accessed data to reduce 
CPU waiting time.
3
Main Memory (RAM)
Moderate speed, larger capacity (GB). Primary working memory for running 
applications.
4
Secondary Storage
Slow, large, persistent storage (HDD/SSD, TB). Retains data when 
power is off.
The memory hierarchy balances speed and cost while providing fast access to frequently used data. Data moves between levels based on usage 
patterns through processes like caching and swapping, optimizing overall system performance.
Types of Memory Allocation
Contiguous Allocation
Process occupies a single contiguous block of memory. 
This approach includes fixed partitioning, where memory is 
divided into predetermined blocks, and dynamic 
partitioning, where memory is allocated based on process 
needs.
Non-Contiguous Allocation
Process memory is spread across non-adjacent locations. 
This includes techniques like paging and segmentation, 
which allow more flexible memory utilization.
Memory allocation strategies aim to minimize fragmentation and optimize memory usage. Internal fragmentation occurs 
when there is wasted space within allocated memory (common in fixed partitions), while external fragmentation refers to 
wasted space between allocated blocks (typical in dynamic partitioning).
Fixed and Dynamic Partitioning
Fixed Partitioning
Memory divided into fixed-size partitions with each 
partition holding one process. Simple to implement but 
suffers from internal fragmentation and limits process 
size.
Dynamic Partitioning
Memory allocated dynamically as processes arrive. Offers 
flexibility with no size limits for processes but leads to 
external fragmentation and requires compaction.
In fixed partitioning, a system with 4 partitions of 8 MB each would waste 2 MB when running a 6 MB process. With dynamic 
partitioning, a 6 MB process would receive exactly 6 MB, but over time, gaps form between allocations as processes 
terminate, leading to fragmentation challenges.