Fragmentation refers to an unwanted problem that occurs in the OS in which a process is unloaded and loaded from memory, and the free memory space gets fragmented. The processes can not be assigned to the memory blocks because of their small size. Thus the memory blocks always stay unused.
In this article, we will look more into the Internal Fragmentation in OS according to the GATE Syllabus for (Computer Science Engineering) CSE. We will read ahead to find out more about it.
Table of Contents
- What is Fragmentation in OS?
- Types of Fragmentation
- Causes of Fragmentation
- Pros and Cons of Fragmentation
- Conclusion
What is Fragmentation in OS?
Fragmentation refers to a process of information storage where the memory space of the system is used inadequately, thus reducing the overall efficiency or ability or both (sometimes). The implications of the process of fragmentation depend entirely on the specific allocation of storage space schemes in the operation along with the particular fragmentation types. In some instances, fragmentation leads to some unused storage capacity. This concept is also applicable to the generated unused space in this very situation.
The memory used for the preservation of the data set (like file formats) is very similar to the other systems (like the FAT file system), irrespective of the amount of fragmentation (it happens from null to the extreme).
Types of Fragmentation
Fragmentation is of three types:
- External Fragmentation
- Internal Fragmentation
- Data Fragmentation (which exists beside or a combination)
Fragmentation can often be acknowledged when preferring enhancements, usability, or inefficiency. Similar things might also happen for the other tools, like processors. Let us discuss what’s the major difference between internal and external fragmentation.
Internal Fragmentation
Whenever a memory block gets allocated with a process, and in case the process happens to be smaller than the total amount of requested memory, a free space is ultimately created in this memory block. And due to this, the memory block’s free space is unused. This is what causes internal fragmentation. Read more on Internal Fragmentation here.
External Fragmentation
External fragmentation occurs whenever a method of dynamic memory allocation happens to allocate some memory and leave a small amount of unusable memory. The total quantity of the memory available is reduced substantially in case there’s too much external fragmentation. So, there’s enough memory space in order to complete a request, and it is not contiguous. Thus, it is known as external fragmentation. Read more on External Fragmentation here.
Causes of Fragmentation
The user processes are unloaded and loaded from the main memory. Also, all the processes are kept in the memory blocks in a system’s main memory. Various spaces are left after the loading and swapping of processes that other processes can’t load because of their sizes. The main memory is available, but the space isn’t sufficient in order to load other processes since the allocation of the main memory processes is dynamic.
Pros and Cons of Fragmentation
Fragmentation comes with various pros and cons. Let us look into some of the prominent ones now.
Pros
Storage optimization
The fragmented systems might make potentially better use of the storage devices by using every storage block available to us.
Fewer failures
If a system has insufficient sequential space, then it won’t support fragmentation and would ultimately fail. No issues would arise.
Fast data writes
The data written in a system supporting data fragmentation can be faster than the reorganizing data storage. It enables data writes in a contiguous manner.
Cons
Need for regular defragmentation
The storage device with more fragmentation would ultimately degrade over time. Thus, there would be a necessary requirement for time-consuming operations of defragmentation.
Slower read times
The amount of time taken to read a non-sequential file may increase when a storage device happens to become more fragmented.
Conclusion
In brief, both external and internal fragmentations are natural processes and these result in either the wastage of memory or empty memory space. Nevertheless, the problems in both cases can’t completely be overcome. But they can be reduced to some extent.
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