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(Redirected from AT form factor)

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 preceded it, AT became a widely used design as a result of the booming home computer market in the 1980s. IBM clones made at the time began using 'AT' compatible designs, contributing to its popularity. In the 1990s many computers still used AT and its variants, but ATX has been the most popular standard since 1997.

Contents

Design

Variants

External links

Design

Main articles: Industry Standard Architecture

The original AT motherboard, later known as "Full AT", is 12 inches (305 mm) wide and 13.8 inches (350 mm) deep, which means it will not fit in "mini desktop" or "minitower cases". The board's size also means that it 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 two power connectors it requires are not easily distinguishable, leading many people to damage their boards when they were misconnected. However, technicians need only remember the phrase "black wires together in the middle" or "red and red and you are dead" to prevent this. The two black wires on either connector must be plugged in back to back, creating a row of 4 black cords (out of the total 12) and a correct connection.

Variants

In 1985 IBM introduced 'Baby AT'. Soon after all computer makers abandoned AT for the cheaper and smaller Baby AT, using it for computers from the 286 processors to the first Pentiums. These motherboards all have the same functionality as those with the AT form factor, but are 2" (51 mm) narrower and marginally shorter. This size (220x330 mm) and the flexibility of this kind of motherboard were the key to success of this format. However, when the chips began to generate heat, Baby AT was consigned to oblivion because the proximity of the components produced an increase in the CPU temperature. While now obsolete, a few computers are still using it, and modern PC cases are generally 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

★ AT power supply connectors with pinouts

★ PC Magazine

★ How to destroy your computer by miswiring the AT power supply connectors.