Hard drive interface: hard drive interface can be divided into the IDE and SATA interfaces. In models older motherboard, integrated 2 IDE port, usually located below the PCI slot IDE interface, from space, perpendicular to the memory slot (also sideways). But the new motherboard, IDE interfaces are reduced, or even no, replace it with SATA interface.
Floppy connector: used to connect floppy drive, located next to the IDE interface, slightly shorter than the IDE interface, because it is the 34-pin, so the data line is slightly narrower.
COM interface (serial port): most of the motherboard provides two COM interfaces, COM1 and COM2, respectively, the role is to connect serial devices such as mouse and an external Modem. The COM1 interface I/O address is 03F8h-03FFh, and interrupt number is IRQ4;COM2 interface I/O address is 02F8h-02FFh, interrupt IRQ3. Thus response than COM1 COM2 interface interface has priority, has been difficult to find on the market of products based on the interface.