On 8 Jan 2003, at 9:44, Huonga3 wrote:

> what are AT and ATX computers?

  In 1983, IBM brought out a new model called the PC/AT.  It was the one of
the first DOS machines to use the new 16-bit member of the x86 CPU family,
the 80286, and included a 16-bit extension to the peripheral slot
architecture and a new, roomier case.
  The case design dictated the type and placement of the keyboard connector
and peripheral slots on the motherboard.  For about 15 years, virtually all
third-party cases and third-party motherboards stuck to those plcements, so
they could be used with each other.

  There were two problems with this:

1.  There wasn't much way to make the case smaller without requiring a
special proprietary motherboard design.

2.  There wasn't much way to incorporate peripherals (video, sound, mouse,
parallel, serial, network, etc....) on the motherboard without requiring a
special proprietary case.

  ATX was a new specification from Intel, introduced around 1996 or so.  In
the process, they also changed how the power supply connects to the
motherboard.

  You can still find -- if you look hard enough -- motherboards, cases, and
power supplies that still use the AT design.  You can find plenty that use
the ATX design, which I believe is still the most common.  There are also
"mini-ATX" and "NTX" designs out there, which I believe are both intended to
allow you to build machines which are physically much smaller, and still buy
your motherboard and case from different suppliers.

David Gillett

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