Device Resources of Hardware & its Description

Interrupt - Hardware devices use interrupts to send messages. The microprocessor knows this as an interrupt
                request (IRQ) and uses this information to determine which device needs its attention and the type of
                attention it needs. There are 16 IRQs (numbered 0 to 15) that Windows XP assigns to devices.  
                e.g. Windows XP assigns IRQ 1 to the keyboard.

Input/output (I/O) port - I/O ports are section of memory that a hardware device uses to communicate with the
                operating system. When a microprocessor receives an IRQ, the OS checks the I/O port address to
                retrieve additional information about what the hardware device wants it to do and it is represented as a
                hexadecimal number.

Direct memory access (DMA) - DMAs are channels that allow a hardware device, such as a floppy disk

drive, to access memory directly, without interrupting the microprocessor. DMA channels speed up access to memory. Windows XP assigns eight DMA channels, numbered 0 through 7.

Memory  - Many hardware devices, such as a network interface card (NIC), use onboard memory or reserve

                system memory. This reserved memory is unavailable for use by other devices or Windows XP

                Professional.