The Difference Between Internal and External Fragmentation in Operating Systems
When it comes to operating systems, fragmentation is a common issue that can impact system performance. There are two types of fragmentation that can occur within an operating system: internal and external. In this article, we’ll take a look at the differences between these two types of fragmentation and explore how they can impact system performance.
What is Internal Fragmentation?
Internal fragmentation occurs when available memory blocks within an operating system are too small to meet the memory requirements of a given process. This happens because the allocated memory block is larger than the actual memory that is required for the process. The unused portion of the allocated memory block is known as internal fragmentation.
Internal fragmentation can cause problems for the system because it leads to wasted resources. When a process requests memory, the system looks for a block of memory that is large enough to accommodate the process. However, if the available memory blocks are smaller than the required memory for the process, the system may have to allocate multiple memory blocks to satisfy the request. This, in turn, can create gaps in memory that cannot be used for any other processes.
What is External Fragmentation?
External fragmentation occurs when free memory blocks within an operating system become scattered across the system in a non-contiguous manner. This type of fragmentation occurs over time as programs are loaded and unloaded from the system memory. As the number of programs running on the system changes, the memory blocks become fragmented, leading to small gaps of unusable memory that can’t be used to satisfy the memory requests of new processes.
External fragmentation can lead to performance issues because the system has to spend more time searching for and allocating memory blocks to new processes. This, in turn, can cause delay in the execution of programs and system tasks.
The Impact of Fragmentation on System Performance
Both internal and external fragmentation can have a negative impact on system performance. Internal fragmentation can cause wasted resources, while external fragmentation can lead to delays in process execution. Over time, the accumulation of both types of fragmentation can lead to decreased system performance and even system crashes.
To prevent fragmentation from impacting system performance, operating systems use various memory management techniques. One of the most common techniques used is memory compaction, which involves relocating memory blocks to create continuous blocks of free memory. Another technique is to use virtual memory, which allows the system to use a portion of the hard disk as a temporary memory location.
In conclusion, fragmentation is a common issue that affects operating systems. Internal fragmentation occurs when available memory blocks are too small to meet process requirements, while external fragmentation occurs when free memory blocks become scattered across the system memory in a non-contiguous manner. To prevent fragmentation from impacting system performance, operating systems use various memory management techniques.
Table difference between internal and external fragmentation
| Attribute | Internal Fragmentation | External Fragmentation |
|---|---|---|
| Description | Unused memory within a process | Unallocated memory between processes |
| Caused by | Allocating memory in fixed sizes, leaving unused space within the allocated memory blocks | Allocating and deallocating memory of varying sizes, leaving fragmented free space between the allocated memory blocks |
| Impact on system efficiency | May cause slower execution and less efficient use of memory space within a process | May cause slower execution and wasted memory space in the system |
| Solution | Memory compaction or use of dynamic memory allocation | Memory defragmentation or use of memory pooling |