It's an <i>Interrupt Request Line</i>. IRQs are hardware lines over which devices can send interrupt signals to the microprocessor.
An interrupt is a signal informing a program that an event has occurred. When a program receives an interrupt signal, it takes a specified action. Interrupt signals can cause a program to suspend itself temporarily to service the interrupt.
Interrupt signals can come from a variety of sources. For example, every keystroke generates an interrupt signal. Interrupts can also be generated by other devices, such as a printer, to indicate that some event has occurred. These are called hardware interrupts. Interrupt signals initiated by programs are called software interrupts. A software interrupt is also called a trap or an exception.
PCs support 256 types of software interrupts and 15 hardware interrupts. Each type of software interrupt is associated with an interrupt handler -- a routine that takes control when the interrupt occurs. For example, when you press a key on your keyboard, this triggers a specific interrupt handler. The complete list of interrupts and associated interrupt handlers is stored in a table called the interrupt vector table (or a dispatch table), which resides in the first 1 K of addressable memory.
Toejam31
<font color=red>My Rig:</font color=red> <A HREF="http://www.anandtech.com/mysystemrig.html?rigid=6847" target="_new"><font color=green>Toejam31's Tantalizing Tantric Toy</font color=green></A>
<font color=red>Second Rig:</font color=red> <A HREF="http://www.anandtech.com/mysystemrig.html?rigid=15942" target="_new"><font color=green>Toey's Dynamite DDR Duron</font color=green></A>
____________________________________________________________
<font color=purple>"Procrastination on your part does not constitute an emergency on my part."</font color=purple>
Facebook
Twitter
Instagram