Priority Interrupt
Priority Interrupt
. Priority interrupt is one of the methods of data transfer from CPU to peripheral devices Data is transferred from CPU to I/O devices on the initiation of CPU. But, the CPU cannot start the transfer unless the device is completely ready for communication with the CPU. The readiness of the device is checked only by the interrupt given by the device. The CPU responds to the request by storing the returned address from PC into the memory stack. Then the next job is of program to service that request by transfer of data.
In a typical system number of I/O devices are connected to the system. Each of the devices is equally capable of producing the interrupt to talk to CPU and transfers the data. The first task of the interrupt handler is to identify the source of the request and the time it originates. Sometime it also happens that the requests generated are simultaneous. In such cases system has to decide which one to be served first.
Priority interrupt is a system which assigns priority to the various devices and arranges them in order to serve them in case of simultaneous requests. The system may also decide determine which conditions are permitted to interrupt the computer while another request is being serviced or in other words it is responsible for determining the interrupting scope of the device. Accordingly we can easily judge which task need to be of higher priority. Tasks which can’t be delayed or interrupted while execution otherwise some serious consequences can happen are always prioritized higher. For example devices like magnetic tapes which have high transfer rate are prioritized higher then the devices with slow data transfer like keyboard. As simple as it can be, the computer will serve that request first who’spriority is higher then the other if there is any conflict between the request creations.
Establishing the priority of the interrupt can be through software or hardware. A polling process is used to identify the highest
. Priority interrupt is one of the methods of data transfer from CPU to peripheral devices Data is transferred from CPU to I/O devices on the initiation of CPU. But, the CPU cannot start the transfer unless the device is completely ready for communication with the CPU. The readiness of the device is checked only by the interrupt given by the device. The CPU responds to the request by storing the returned address from PC into the memory stack. Then the next job is of program to service that request by transfer of data.
In a typical system number of I/O devices are connected to the system. Each of the devices is equally capable of producing the interrupt to talk to CPU and transfers the data. The first task of the interrupt handler is to identify the source of the request and the time it originates. Sometime it also happens that the requests generated are simultaneous. In such cases system has to decide which one to be served first.
Priority interrupt is a system which assigns priority to the various devices and arranges them in order to serve them in case of simultaneous requests. The system may also decide determine which conditions are permitted to interrupt the computer while another request is being serviced or in other words it is responsible for determining the interrupting scope of the device. Accordingly we can easily judge which task need to be of higher priority. Tasks which can’t be delayed or interrupted while execution otherwise some serious consequences can happen are always prioritized higher. For example devices like magnetic tapes which have high transfer rate are prioritized higher then the devices with slow data transfer like keyboard. As simple as it can be, the computer will serve that request first who’spriority is higher then the other if there is any conflict between the request creations.
Establishing the priority of the interrupt can be through software or hardware. A polling process is used to identify the highest