What is Interrupt and Why is it Very Important?

Posted on
What is Interrupt? why is it important in Computer Systems


Currently, almost all of us have used computers, be it laptops, PCs to AIOs. However, behind the complex functions that exist in a computer, there is a concept known as an interrupt. In this article, I will to you what interrupts. how it works, and its advantages in modern computer systems.

Later you will see why interrupts are so used in computer systems. I will also provide examples of implementing interrupts in modern computer systems. Let’s start!

What are Interrupts?

The interrupt is a mechanism in the processor that has the function of reading certain signals. If the signal is read, the processor will perform an action immediately. When an interrupt occurs, the processor will stop the current program and switches to the appropriate program according to the interrupt signal.

These signal can originate from a variety of sources, such as :

  • Hardware (for example, a keyboard key is pressed, or a signal from a network)
  • Software (for example, a programming error)

Without interrupts, the computer system would be stuck in executing programs that run without response to outside events, such as user input or signals from other devices. With interrupts, the computer can respond quickly to these events and provide responsive interactions to users.

How Do Interrupts Work?

When an interrupt occurs, the processor will respond by stopping the execution of the program that is currently running. The processor stores the address of the current instruction and the status register on the stack, so that the program can later return to the point of pending execution after interrupt handling is complete.

After saving the current execution context, the processor searches for and executes the appropriate interrupt handling routine. This routine is a predetermined set of instructions and will handle the event that caused the interrupt. After interrupt handling is complete, the processor restores the previous execution context and resumes execution of the pending program.

Types of Interrupts

There are several types of interrupts that are often used in computer systems. Here are some of them:

  • Interrupt Maskable (Non-Maskable)
    This type can be enabled or disabled by the user program. The program can choose to ignore the interrupt or respond with appropriate handling routines. Non-maskable interrupts, on the other hand, cannot be ignored by the program and usually indicate important events that require immediate attention.
  • External Interrupts
    This type occurs when an external event such as a signal from hardware or user input triggers an interrupt. Common examples of external interrupts are when a keyboard key is pressed or when data arrives from the network.
  • Timer Interrupts
    This type occurs when the internal timer in a computer system reaches a certain time limit. Timer interrupts are often used to schedule processing and multitasking in operating systems.
  • Exception Interrupts
    Exception interrupts occur when an abnormal condition occurs in the system, such as a programming error, division by zero, or invalid memory access. Exception interrupt indicates a situation that requires special handling.

Benefits and Advantages of Interrupts

The use of interrupts, like in software development offers a number of benefits and advantages. Here are some of them:

  • Responsive to External Events
    With interrupts, software can respond to outside events quickly and efficiently. For example, in real-time data processing applications, interrupts allow the system to respond instantly to user input or hardware signals, without having to wait for program execution to complete.
  • Efficient Use of Resources
    Interrupts allow computer systems to use resources efficiently. With interrupts, the CPU doesn’t need to constantly check hardware status or wait for input from the user. The CPU will only spend time handling interrupts when needed, thereby reducing wastage of resources.
  • Multitasking ability
    In modern operating systems, interrupts enable multitasking capabilities, where several tasks can be executed simultaneously. Interrupts can be used to schedule processing, divide CPU time between different tasks, and ensure that each task gets sufficient execution time.

Challenges and Problems that Might Arise in Interrupt Implementation

Although interrupts have many benefits, their implementation can also pose certain challenges and problems. Following are some of the challenges that may arise in interrupt implementation:

  • Error Control
    In the use of interrupts, there needs to be good control over errors and exception handling. If interrupt handling is not done properly, it can lead to system failure or security vulnerabilities.
  • Deadlocks and Starvation
    If interrupts are not handled properly, deadlock or starvation can occur where the interrupt is delayed or trapped in an endless loop. This can result in poor system performance or unresponsiveness.
  • Interrupt Priority Setting
    In a complex system, it is necessary to set interrupt priority. If the interrupt priority is not set correctly, important events may not get timely handling, or less important events may interrupt the execution of more critical tasks.

Optimizing Interrupt Usage to Increase System Performance

To optimize the use of interrupts in a computer system, here are some steps that can be taken:

  • Interrupt Priority Setting
    It is important to set proper interrupt priorities, so that critical events get handled promptly and less important events do not interrupt the execution of more important tasks.
  • Avoiding Excessive Interrupts
    Too many triggered interrupts can affect system performance. Therefore, it is necessary to carefully consider the number and frequency of interrupts used so as not to overload the CPU.
  • Implement Efficient Interrupt Handling
    Interrupt handling routines must be optimized to run quickly and efficiently. This can involve using efficient data structures, rearranging task priorities, or using more lightweight interrupt handling mechanisms.

Read more: Interrupt in AVR Microcontroller

In conclusion, in computer systems, interrupts have a very important role in enabling responsive interaction between hardware and software. Interrupts allow the system to respond quickly to outside events, ensure a good user experience, and enable efficient use of resources. Although the implementation of interrupts can present challenges, with the right setup and efficient handling, interrupts can be used to improve the performance and functionality of the computer system as a whole.

Leave a Reply