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I/O Ports

Multi-I/O cards

Multi-I/O cards used to be a single card with the following devices:
A multi-I/O card with SCSI. The parallel port and one serial port are D-Sub connectors on the back of the card (right side of the picture). The second serial port and game port are the headers in the upper right. These would be connected to D-Sub connectors by ribbon cables (as shown below for ATA motherboards). Along the top are SCSI, a single IDE, and a Floppy disk connector

Misnomer:

Computer literature often calls the D-Sub connector a "DB" connector. For example, you will see references to "DB-9", "DB-15", "DB-25", etc. This is because Canon's designation for a 25-pin D-Sub connector was DB-25. Actually, the 15-pin D-Sub connector is the DA-15, the 25-pin is the DB-25, and the 9-pin is the DE-9 in Canon's system. Properly, these should be called D-Sub or D-Type connectors. In the end, things are what people call them. DB-9 or DB-15 rolls off the tongue well; people will know what you are talking about.
A male DE-9 connector. Most people call it a DB-9M.

Older multi-I/O cards were configured with jumper blocks. Technicians physically moved jumpers to different header pins to configure resources. Later, multi-I/O cards stored their configurations in flash memory. To configure such a card, you had to run a program that came on a supplied floppy disk to configure the card.

ATA Motherboards

When the ATA hard disk specification was implemented, it required an upgrade in the BIOS to handle the new drive type. Existing multi-I/O cards also wouldn't work with ATA hard drives. The devices usually found on the multi-I/O card (except the joystick port) were incorporated into the ATA motherboard, eliminating the need for multi-I/O cards. All ATA motherboards had integrated I/O, and most older motherboards didn't. The parallel port and serial port connections on ATA motherboards always consisted of headers that used ribbon cables to carry the signals to I/O slot covers.
A serial port and a parallel port on a slot cover with ribbon cables to connect to an ATA motherboard.

ATA motherboards didn't have a joystick port. A joystick and sound were usually associated with games, so sound cards usually came with joystick ports. This was before watching movies, etc., on computers became common, so most users didn't need sound unless they were playing games. Thus, the joystick was typically associated with the need for sound.

ATX Motherboards

The current generation of motherboard is ATX. The most obvious feature of the ATX motherboard is that the I/O connectors are in a cluster on the back of the board. There are few, if any, ribbon cables going to headers.
An ATX motherboard focusing on the cluster of I/O connectors.

ATX motherboards without sound did not have joystick ports, but motherboards with sound did on early boards. The joystick port disappeared when USB joysticks replaced old-style ones.

With the I/O devices on the motherboard, configuration software is now in the system setup program. There will be an option for onboard peripherals where you can set I/O addresses, IRQs, etc., although the default values usually work unchanged.

Before USB keyboards and mice became prevalent, the ATX motherboard used PS/2 connectors for the mouse and keyboard. These are 6-pin mini-DIN connectors. They are called PS/2 connectors because they were introduced on the IBM PS/2 in 1988. USB mice and keyboards are virtually universal now, so the PS/2 connectors are not on the newer motherboards.

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