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
Inter-process communication and Synchronization
Introduction to Process Synchronization
The process is characterized into two types
i) Co-operative processes
ii) Independent/Isolated processes
Two or more processes are said to be co-operative, if they get affected or affects the execution of other processes i.e. the execution of two or more processes are dependent on each other otherwise they said to be independent.
Cooperative processes can either directly share a logical address space (both code, data) or be allowed to share data only through files or messages. They can also be shared common resources, memory space, etc.
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An important and fundamental feature in modern OS is the concurrent execution of processes.
Process synchronization is for the realization of
- Multiprogramming
- Multiprocessing
- Distributed system
- Client-server model
The problem can occur in two ways
1) When two processes have the accessibility of shared resources or variables.
Example: When two processes P1 and P2 try to update the value of the shared variable.
This problem leads to inconsistency and loss of data.
2) Due to cooperating processes where Execution of one process affects the other processes.
Example: Producer-consumer problem.
This problem leads to a deadlock.
Global Shared Variable: This variable is accessible by multiple processes P1, P2,.....Pn.
Shared Resources: Resources like printer, memory, CPU, file and I/P device, etc. which can be shared among multiple processes.
Shared code: Code accessible by multiple processes. Example: Kernel Code.
To avoid such inconsistency problems, we introduced process synchronization to handle problems while concurrent processes occur.
For example (Data Inconsistency problem)
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