Difference between Trap and Interrupt in Operating System

An operating system is in charge of controlling a computer system's resources and acting as an interface between the hardware and software. The management of events that arise during the execution of programmes is a crucial component of operating system design. Traps and interrupts are two often utilised methods for this purpose.

• A trap is a computer-generated occurrence that results from an error or exception in the programme that is running at the time. Division by zero, page errors, and illegitimate instructions are a few examples of traps. The CPU instantly enters kernel mode after a trap occurs and hands off control to the operating system's trap handler, which is in charge of handling the error and taking the necessary action (such as terminating the program).

• Contrarily, an interrupt is a hardware-generated event brought on by a timer or an external device (like a keyboard or mouse).

What is a Trap in Operating System?

A trap in an operating system is a software-generated interruption brought on by an error or exception that happens while a programme is being executed. When a trap occurs, the CPU switches from user mode to kernel mode and jumps to the trap handler, a predefined point in the operating system. Traps can happen for a number of reasons, including division by zero, accessing erroneous memory addresses, carrying out erroneous instructions, or other unanticipated occurrences that might force the programme to crash or yield inaccurate results.

Traps can also be purposefully created by the software to ask the operating system for a particular service, such reading from a file or allocating memory. The operating system's trap handler is in charge of managing the trap and taking the proper action in accordance with the trap's cause. For instance, if an unlawful instruction set off the trap, the trap handler may terminate the programme and notify the user of the error. The trap handler may carry out the requested service and transfer control back to the programme if the trap is brought on by a request for a particular service.

How Do Traps Function?

The following stages can be used to summarise how a trap operates in an operating system −

• A divide-by-zero error, an attempt to access erroneous memory, or an invalid instruction are examples of errors or exceptions that might happen while a program is being executed. The CPU generates a trap signal after identifying the fault or exception.

• With the help of this signal, the CPU enters kernel mode and transfers control to the trap handler, a predetermined area of the operating system.

• The operating system's trap handler ascertains the origin of the trap and takes the necessary action. This could entail ending the programme, informing the user of an error, or providing a specific service that the programme has requested.

• Control is returned to the programme that created the trap after the trap handler has finished its job, and the CPU returns to user mode.

What is an Interrupt in Operating System?

A hardware device, such as a keyboard, mouse, or disc drive, can send an interrupt signal to an operating system, which instructs the CPU to briefly pause the execution of the programme that is now running and switch to another task. In current computer systems, interruptions are a crucial technique for providing input/output (I/O) services and multitasking.

When an interrupt happens, the CPU immediately transitions from user mode to kernel mode and hands off command to the interrupt handler of the operating system. After identifying the interrupt's origin, the interrupt handler takes the necessary action, such as reading data from the device or carrying out additional I/O activities.

Hardware interrupts and software interrupts are the two categories into which interrupts may be divided.

• Software interruptions are produced by software running on the CPU, whereas hardware interrupts are produced by external hardware components.

• Maskable interrupts and non-maskable interrupts are the additional categories into which hardware interrupts are divided. Software can allow or disable maskable interrupts, but the system cannot ignore or disable non-maskable interrupts.

How Do Interrupts Function?

The following stages can be used to summarise how an interrupt functions in an operating system:

• An interrupt signal is produced by an external hardware device to let the CPU know that it needs to be attended to. The operating system can handle the interrupt because the CPU suspends the presently executing program's execution and enters kernel mode.

• To handle the interrupt, the operating system calls its interrupt handler. When an interrupt occurs, the interrupt handler locates its origin and responds appropriately by reading data from the device or carrying out other input/output (I/O) actions.

• The interrupted program resumes execution at the place where it was suspended after the interrupt has been dealt with.

Hardware interrupts and software interrupts are the two categories into which interrupts may be divided. Software interruptions are produced by software running on the CPU, whereas hardware interrupts are produced by external hardware components.

Difference between Traps and Interrupts in Operating System

The following table highlights the major differences between Traps and Interrupts:

Trap	Interrupt
The trap is a signal that a user software sends to the operating system telling it to carry out particular activity right away.	The interrupt is a signal from hardware that tells the CPU that something has to be attended to right away.
The procedure is synchronized.	The process is asynchronous.
Every trap is interruptible.	Not every interruption is a trap.
That might only occur from software-based devices. Devices' hardware and software could be at fault.	That might only occur from software-based devices. Devices' hardware and software could be at fault.
It is generated by a user programme instruction.	They are produced by hardware.
A software interruption is another name for it.	It is also known as a hardware interrupt.
The operating system's specialised functionality is carried out, and the trap handler is given control.	It compels the Processor to launch a particular interrupt handler programme.

Conclusion

To summarise, traps and interrupts are two crucial operating system components that enable the CPU to manage faults, exceptions, and outside events. Software creates traps, which are used to manage errors and exceptions that happen while a programme is being executed. Contrarily, interrupts are produced by external hardware and are used to manage input/output operations and react to in-the-moment occurrences.

Traps and interrupts both require putting the CPU in kernel mode and giving the operating system control, but they come from distinct sources and serve different objectives. For the creation of effective and dependable operating systems, it is essential to comprehend the distinctions between traps and interrupts.