CREATE OWN LIBRARY
- Introduction: OS
- Booting Process
- Command Interpreter
- Dual mode of operation
- System Calls
- Difference between system call and library call
- Interrupt and Trap
- Introduction
- Scheduling Criteria, Terms and Concepts
- Different Type Scheduling Algorithms
- Longest Job First
- Longest Remaining Time First
- Highest Response Ratio Next (HRRN)
- Priority Scheduling
- Least Completed Next (LCN) Scheduling
- Multi-Level Queue Scheduling
- Multilevel Feedback Queue Scheduling
- Guaranteed Scheduling
- Fair Share Scheduling
- Lottery Scheduling
- Multi-Processor Scheduling
- Deadline Scheduling
- Rate-Monotonic Scheduling
- POSIX Real-Time Scheduling
- Priority Inversion
- Proportional Share Scheduling
- Comparison table of Scheduling Algorithm
- Algorithm Evaluation for Scheduling
- Important concept of MM
- Memory Representation as Address
- Memory layout for a Process
- Logical and Physical Address Space
- Necessity of Memory Management
- Introduction
- Concept of Non-contiguous memory allocation
- Basic concept of Paging
- Address Translation
- Process of Paging Method
- Calculation of Offset for paging
- Calculation of Logical Address Bit and number of Pages
- Calculation of Physical Address Bit and number of Frames
- Calculation of Page Table Size
- Organization of MMU
- Why Page size power of 2
- Paging Address Calculation: example1
- Paging Numeric Problem: Example2
- Paging Address Calculation: Example3
- Paging Address Calculation: Question1
- Some Important Question 2
- Paging Address Translation: Question3
- UGC NET Paging Question
- GATE Paging Question
- Number of information at Page Entry
- Exams Question on Page Entry Information
- Exam Question: Page Entry Information
- Calculates Page Table Entry Size
- Calculates Page Size
- Calculation of Optimal Page Size
- Question on Optimal Page Size
- Hashed Page Table with Example
- Inverted Page Table with Gate Question
- Question on Inverted Page Table
- Multi-Level Paging
- Multi-level paging: Example1
- Multi-level paging: Example2
- Allocation of Frames
- Subject Mock
Dynamic Partition:
In the dynamic partition technique, memory allocated dynamically for each process, unlike a fixed partition.
We know in fixed partition technique there is a major disadvantage is an internal fragmentation.
And here due to internal fragmentation also external fragmentation occurred.
Initially, the whole memory is free not divided with a fixed partition and as per the requirement of the current process, it can dynamically allocated memory.
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So, at dynamic partition, it is clear that internal fragmentation never be happened.
But in dynamic partition external fragmentation can be occurred.
For example:
# Let’s assume that process P1 and P3 with size 1 MB and 4MB is finished, so, they are swap out and 2 MB and 4 MB memory is free.
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At this time a new process P5 with size 5MB try to enter into the main memory. But consecutively 5MB memory space is not free.
Though a total of 5MB free space is available in memory it is not serially available so, process P5 is not possible to allocate into memory at this moment.
Still, we have available free space at the memory but we cannot be allocated the process because it is not a consecutive way, this is called external fragmentation.
# So, the main reason for external fragmentation is contiguous memory allocation, not internal fragmentation.
To avoid contiguous memory allocation we use the paging technique.
Advantages of Dynamic Allocation:
1. Degree of multi-programming is dynamic, not fixed.
2. No Internal fragmentation.
3. Size of the process is not limited by the size of a partition.
Disadvantages of Dynamic Allocation:
1. External fragmentation
2. Allocation and de-allocation of memory are complex.
