OS Services

Operating Systems Services:

1. Program execution:

• The operating system Loads program into memory
• It Handles the program’s execution
• It Provides a mechanism for process synchronization
• It Provides a mechanism for process communication

2. I/O operations:

• OS manages the communication between the user and devices drivers.
• I/O operations are the read or write operations which are done with the help of input-output devices.
• Operating system give the access to the I/O devices when it required.

3. File system manipulation:

• The OS gives an access to the program for performing an operation on the file.
• The user can create/delete a file by using an interface provided by the OS.
• The backup of the file system can be created by using an interface provided by the OS.

4. Communication:

• The operating system manages communication between all the processes.

5. Error detection:

• The OS continuously checks for the possible errors.
• The OS takes an appropriate action to correct errors and consistent computing.

6. Resource allocation:

• The OS manages all kinds of resources using schedulers.
• CPU scheduling, Disk scheduling algorithm etc are used for better utilization.

7. Protection:

• The OS ensures that all access to system resources is controlled.
• The OS ensures that external I/O devices are protected from invalid access attempts.
• The OS provides authentication features for each user by means of passwords.

Operating Systems:

EasyExamNotes.com covered following topics in Operating Systems.

• Introduction to Operating Systems
• Function of OS
• Evolution of OS 
• Different Types of OS
• Desirable Characteristics and features of an OS
• Operating Systems Services
• Utility Programs
• System Calls
• File Systems: File Concept
• Contiguous disk space allocation met
• Directory Structures
• Disk Scheduling Algorithms
• FCFS Disk Scheduling Algorithms
• SSTF Disk Scheduling Algorithms
• SCAN Disk Scheduling Algorithms
• CSCAN Disk Scheduling Algorithms
• LOOK Disk Scheduling Algorithms
• CLOOK Disk Scheduling Algorithms.
• CPU Scheduling
• CPU Scheduling Concepts
• CPU Scheduling Algorithms
• FCFS CPU scheduling algorithm
• Nonpreemptive SJF CPU scheduling algorithm
• Preemptive SJF (SRTF) CPU scheduling algorithm
• Round Robin CPU scheduling algorithm
• Process Concept
• Process State Diagram
• Types of Schedulers
• System calls for Process Management
• Multiple Processor Scheduling
• Concept of Threads
• Memory Management
• Different Memory Management Techniques
• Swapping
• Segmentation
• Paging
• Paging vs Swapping
• Paging vs Segmentation
• Overlay in memory management
• FCFS page replacement algorithm
• LRU page replacement algorithm 
• Optimal page replacement algorithm
• Critical Section Problem
• Deadlock Avoidance, Recovery

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