[]

	"These LPT1, COM1, disk controller are call devices.  There are
	devices that requires exclusive interrupt ownership, eg. disk
	controller (I6) and keyboard (I1).  There are also devices that
	does not require exclusive ownership, ie. it will share an
	interrupt with another device, eg. LPT1"

No.  In a standard ISA bus, the one that almost all non-laptop PCs use,
two separate interface cards cannot share an interrupt.  This is due to
a screwup in the bus design.  For example, if your Soundblaster wants
to drive interrupt number 7, then it must hold a certain bus wire to 0
or 1 at all times, depending on whether or not it wants an interrupt.
This precludes letting another card assert interrupt number 7.

When two or more devices in an ISA bus PC share an interrupt, it's
because they're implemented by a single card.