operating system presentation use critical fifo

operating system

1. ASSIGNMENT NO :1 SUBMITTED TO: Ms.Saima SUBMITTED BY: Ali jan SUBJECT: Operating system Department: CS&IT CLASS: 4 th Evening Session (B)

2. Interrupt Handling : Interrupts are signals sent by hardware or software to the CPU to request its attention. When an interrupt occurs, the CPU temporarily stops its current execution and transfers control to a specific interrupt handler routine. The operating system manages these interrupt handlers. Interplay b\W operating system software and interrupt mechanism .

3. 2- Interrupt Service Routines (ISRs ) : These are small segments of code within the operating system that handle specific types of interrupts. When an interrupt occurs, the CPU looks up the appropriate ISR and executes it. ISRs typically handle tasks such as servicing I/O devices, handling timer events, or managing errors

4. 3-Device Drivers : Device drivers are software components within the operating system that enable communication between the operating system and peripheral devices such as keyboards, mice, disks, and network interfaces. When an interrupt is generated by a device, the corresponding device driver's ISR is invoked to handle the interrupt and perform any necessary actions.

5. 4-Interrupt Prioritization and Handling : The operating system manages interrupt prioritization to ensure that critical tasks are handled promptly. It may prioritize interrupts based on their importance and the needs of the system. The operating system may also employ techniques such as interrupt masking and interrupt nesting to manage multiple interrupts efficiently . 5-Context Switching : Interrupts can trigger context switches, where the CPU switches from executing one process to another . The operating system is responsible for managing the state

6. of the interrupted process, saving its context, and restoring the context of the newly scheduled process . 6-Resource Management : The operating system coordinates access to system resources among different processes and devices. Interrupts play a crucial role in resource management by allowing devices to signal when they need attention or when data is ready to be processed.

7. Interrupts "drive" the actions of the operating system by serving as triggers for various essential tasks and events. 1-Asynchronous Events Handling : Interrupts allow the operating system to handle asynchronous events generated by hardware devices or other software processes. For example, when a keyboard sends a signal indicating that a key has been pressed, an interrupt is generated, prompting the operating system to read and process the input. How interrupts "drive" the actions of the operating system

8. 2-Task Scheduling : Interrupts play a crucial role in task scheduling by allowing the operating system to preempt the currently executing task and switch to another task when necessary. For instance, a timer interrupt can trigger a context switch to ensure that multiple processes receive fair access to the CPU. 3- I/O Operations : Interrupts are essential for managing input/output operations. When a peripheral device completes an I/O operation or requires attention, it generates an interrupt, prompting the operating system to initiate or complete the corresponding I/O operation.

9. 4-Error Handling : Interrupts are used for error handling and recovery within the operating system. When hardware errors or exceptional conditions occur, interrupts can notify the operating system, enabling it to take appropriate corrective actions or generate error messages. 5-Resource Management : Interrupts facilitate resource management by allowing devices to signal when they require attention or when data is available for processing. This helps the operating system efficiently manage system resources such as CPU time, memory, and I/O devices.

10. 1-Interrupt Generation : Hardware Interrupts : Hardware devices such as timers, I/O controllers, or other peripherals generate hardware interrupts to signal events requiring the CPU's attention. For example, when a key is pressed on the keyboard, the keyboard controller may generate an interrupt. Software Interrupts : Software interrupts, also known as traps or exceptions, are generated by the CPU in response to exceptional conditions detected during program execution, such as division by zero or invalid memory access H ow the interrupt mechanism in a modern computing system actually works?

11. 2-Interrupt Handling by the CPU : When an interrupt occurs, the CPU temporarily suspends the execution of the currently running program. The CPU saves the current state of the program, including the program counter (PC) and other relevant registers, onto the stack or in designated memory locations. The CPU then determines the type of interrupt that occurred and identifies the corresponding interrupt handler routine to execute. This involves consulting an interrupt vector table or a similar data structure that maps interrupt numbers or types to the addresses of the corresponding interrupt handler routin

12. 3-Execution of Interrupt Service Routine (ISR ) : The CPU transfers control to the appropriate interrupt handler routine, also known as the Interrupt Service Routine (ISR) or Interrupt Handler. The ISR performs the necessary actions to handle the interrupt. This may involve tasks such as servicing the hardware device that triggered the interrupt, updating system state, or initiating I/O operations. The ISR may interact with device drivers, perform data transfer operations, or communicate with other system components as needed to handle the interrupt.

13. 4-Interrupt Acknowledgment : In some systems, especially in older architectures, the CPU may need to send an acknowledgment signal to the interrupt controller or the interrupting device to confirm receipt of the interrupt request. This step may involve acknowledging the interrupt at the hardware level to prevent the same interrupt from being re-triggered. 5-Resumption of Program Execution : After the ISR completes its execution, the CPU restores the saved state of the interrupted program, including the program counter and register values. The CPU resumes execution of the interrupted program from the point where it was interrupted, allowing the program to continue its execution as if the interrupt had not occurred.