The AT form factor is the first modern form factor to be widely used. AT (Advanced Technology) was released in 1984 by IBM. Unlike the PC and XT form factors that proceeded it, AT became a widely used design. IBM clones made at the time began using AT compatible designs, contributing to its popularity. To this day many computers still use AT and its variants.

Design

Main Article: AT bus architecture

AT wasn't a very large technological jump from older form factors. The AT's largest advancement was its "tower" design and a remote power switch in the front. The AT power supply provided 192 watts, a triple that of older form factors.

The AT motherboard is 12 inches (305 mm) which means it won't fit in "mini desktop" or "minitower cases". The board's size also means that is takes up space behind the drive bays making installation of new drives more difficult. The power connectors for AT motherboards are two nearly identical 6-pin cords. Unfortunately, the power two connectors it requires are not physically distinguishable leading many people to damage their boards when they were misconnected.

Variants

In 1985 IBM introduced Baby AT. Soon all computer makers abandoned AT for the cheaper and smaller Baby AT. These motherboards have the same functionality as ATs but are 2" (51 mm) narrower and marginally longer. Although the Baby AT form factor is obsolete many computers are still using it, and modern PC cases are backwards compatible to fit Baby AT.

In 1995 Intel introduced ATX a modern form factor which has quickly replaced older Baby AT computers.

External links

• Motherboards of AT and Baby AT
• Baby AT Power Supply
• Baby AT Case
• Full AT Case
• Full AT Power Supply
• ATX Power Supply Links