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IEventsIRQ

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IRQ

Acronym for: Interrupt Request

The IRQ indicates which priority the data sent by a certain device is handled with by other system  ?resources (means, it indicates with which priority a Interrupt Event by a device is handled).

There are IRQ's from 0 to 15, they are handled with different priorities, build up as follows:

	IRQ Priority Table
	IRQ 0			<<--- most important IRQ
	IRQ 1  
	IRQ 2/9  
	IRQ 10  
	IRQ 11  
	IRQ 12  
	IRQ 13  
	IRQ 14  
	IRQ 15  
	IRQ 3  
	IRQ 4  
	IRQ 5  
	IRQ 6  
	IRQ 7  
	IRQ 8			<<--- The most insignificant IRQ

In normal cases the IRQ's are given to the systems devices as follows:

	Standard IRQ allocation
	IRQ 0	System timer interrupt from TIMER-0. No user-definable 
		options.  
	IRQ 1	Keyboard controller  
	IRQ 2	Cascade for IRQs 8-15. IRQ 9 cascade to IRQ 2 through a 
		software redirect.  
	IRQ 3	Available. The standard IRQ for COM 2/COM 4.  
	IRQ 4	Available. IRQ 4 is the standard for COM 1/COM 3 - the serial 
		mouse connection. Don't try to have the mouse share an IRQ.  
	IRQ 5	Available. This is the default IRQ for most sound cards. 
		Network card and LPT 2 are often set to IRQ 5, IF a sound 
		card is not used.  
	IRQ 6	Floppy Drive controller. No user-definable options.  
	IRQ 7	Primary parallel (printer) port - LPT 1. If a parallel port 
		is not used, then IRQ 7 can be assigned to another device.  
	IRQ 8	Real Time Clock. No user-definable options.  
	IRQ 9	Cascades to IRQ 2.  
	IRQ 10	Available. If a sound card is using IRQ 5, then this IRQ can 
		be used for a network card.  
	IRQ 11	Available. Often used for a SCSI controller.  
	IRQ 12	Available. Often used for the PS2 style mouse.  
	IRQ 13	Math Coprocessor. No user-definable optinos.  
	IRQ 14	Primary IDE (hard drive, CD ROM) controller. The 2 IDE 
		devices on the same cable use the one IRQ.  
	IRQ 15	Secondary IDE channel. Available if the secondary channel is 
		disabled.

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