expansion slot

Expansion Card

Fitting an expansion card into a motherboard
Date Invented:1974
Invented By:MITS
Connects to:
Card Types:
An expansion card (also expansion board, adapter card or accessory card) in computing is a printed circuit board that can be inserted into an expansion slot of a computer motherboard to add additional functionality to a computer system. One edge of the expansion card holds the contacts (the edge connector) that fit exactly into the slot. They establish the electrical contact between the electronics (mostly integrated circuits) on the card and on the motherboard.

Connectors mounted on the bracket allow the connection of external devices to the card. Depending on the form factor of the motherboard and case, around one to seven expansion cards can be added to a computer system. There are also other factors involved in expansion card capacity. For example, some expansion cards need two slots like some NVidia GeForce FX and newer GeForce graphics cards and there is often a space left to aid cooling on some high-end cards.

Some cards are "low-profile" cards, meaning that they take up little physical space. (There is a "low profile PCI card" standard [1] [2] that specifies a much smaller bracket and board area). The group of expansion cards that are used for external connectivity, such as a network, SAN or modem card, are commonly referred to as input/output cards (or I/O cards).

Dimensions for the metal plate on the expansion card is 120mm wide, and 18mm high.

History of the expansion card

The first microcomputer to feature a slot-type expansion card bus was the Altair 8800, developed 1974-1975. Initially, implementations of this bus were proprietary (such as the Apple II and Macintosh), but by 1982 manufacturers of Intel 8080/Zilog Z80-based computers running CP/M had settled around the S-100 standard. IBM introduced the XT bus, with the first IBM PC in 1981; it was then called the PC bus, as the IBM XT, using the same bus (with slight exception,) was not to be introduced until 1983. XT (a.k.a. 8-bit ISA) was replaced with ISA (a.k.a. 16-bit ISA,) originally known as AT bus, in 1984. IBM's MCA bus, developed for the PS/2 in 1987, was a competitor to ISA, also their design, but fell out of favor due to the ISA's industry-wide acceptance and IBM's closed licensing of MCA. EISA, the 16-bit extended version of ISA championed by Compaq, was common on PC motherboards until 1997, when Microsoft declared it a "legacy" subsystem in the PC 97 industry white-paper. VESA Local Bus, an early 1990s expansion bus that was inherently tied to the 80486 CPU, became obsolete (along with the processor) when Intel launched the Pentium CPU in 1993.

The PCI bus was introduced in 1991 as replacement for ISA. The standard (now at version 3.0) is found on PC motherboards to this day. Intel introduced the AGP bus in 1997 as a dedicated video acceleration solution. Though termed a bus, AGP supports only a single card at a time. From 2005 PCI-Express has been replacing both PCI and AGP. This standard, approved [by who?] in 2004, implements the logical PCI protocol over a serial communication interface.

After the S-100 bus, this article above mentions only buses used on IBM-compatible/Windows-Intel PCs. Most other computer lines that were not IBM compatible, including those from Tandy, Commodore, Amiga, and Atari, offered their own expansion buses. Even many video game consoles, such as the Sega Genesis, included expansion buses; at least in the case of the Genesis, the expansion bus was proprietary, and in fact the cartridge slots of many cartridge based consoles (not including the Atari 2600) would qualify as expansion buses, as they exposed both read and write capabilities of the system's internal bus. However, the expansion modules attached to these interfaces, though functionally the same as expansion cards, are not technically expansion cards, due to their physical form/

For their 1000 EX and 1000 HX models, Tandy Computer designed the PLUS expansion interface, an adaptation of the XT-bus supporting cards of a smaller form factor. Because it is electrically compatible with the XT bus (a.k.a. 8-bit ISA or XT-ISA,) a passive adapter can be made to connect XT cards to a PLUS expansion connector. Another feature of PLUS cards is that they are stackable. Another bus that offered stackable expansion modules was the "sidecar" bus used by the IBM PCjr. This may have been electrically the same as or similar to the XT bus; it most certainly had some similarities since both essentially exposed the 8088 CPU's address and data buses, with some buffering and latching, the addition of interrupts and DMA provided by Intel add-on chips, and a few system fault detection lines (Power Good, Memory Check, I/O Channel Check.) Again, PCjr sidecars are not technically expansion cards, but expansion modules, with the only difference being that the sidecar is an expansion card enclosed in a plastic box (with holes exposing the connectors.)

Expansion slot standards

Expansion card types

External links

Motherboard

The ASUS CUSL2-C motherboard

Connects to:
  • Microprocessors via sockets
  • Main memory via Slots
  • Peripherals

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Micro Instrumentation and Telemetry Systems (MITS) was an Albuquerque, New Mexico company founded in 1969 by Forrest Mims and Ed Roberts.[1] Initially MITS designed instrumentation and telemetry systems for the model rocket hobbyist market.
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ISA
Industry Standard Architecture

Five 16-bit and one 8-bit ISA slots on a motherboard
Year created: 1981
Created by: IBM
Superseded by: PCI (1993)


Width:

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PCI
Peripheral Component Interconnect

five 32-bit PCI expansion slots on a motherboard
Year created: Mid-1993
Created by: Intel
Superseded by: PCI Express (2004)


Width:

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AGP
Accelerated Graphics Port

An AGP slot (maroon, although the color is usually brown) and two PCI slots
Year created: 1997
Created by: Intel
Superseded by: PCI Express (2004)



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This article or section may be confusing or unclear for some readers.
Please [improve the article] or discuss this issue on the talk page. This article has been tagged since February 2007.
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Connects to:
  • Motherboard via one of
    • PCI
    • AGP
    • PCI Express
  • Display via one of

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Sound Card

A Sound Blaster Live! Value card, a typical present-day PCI sound card

Connects to:
  • Motherboard via one of

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Network Card

A 1990s Ethernet network interface controller card which connects to the motherboard via the now-obsolete ISA bus.

Connects to:
  • Motherboard via one of

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Modem (from modulate and demodulate) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information.
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computing is synonymous with counting and calculating. Originally, people that performed these functions were known as computers. Today it refers to a science and technology that deals with the computation and the manipulation of symbols.
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printed circuit boards, or PCBs, are used to mechanically support and electrically connect electronic components using conductive pathways, or traces, etched from copper sheets laminated onto a non-conductive substrate.
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computer is a machine which manipulates data according to a list of instructions.

Computers take numerous physical forms. The first devices that resemble modern computers date to the mid-20th century (around 1940 - 1941), although the computer concept and various machines
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Motherboard

The ASUS CUSL2-C motherboard

Connects to:
  • Microprocessors via sockets
  • Main memory via Slots
  • Peripherals

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edge connector is the portion of a printed circuit board consisting of traces leading to the edge of the board that are intended to plug into a matching socket.

An edge connector socket, often popularly referenced simply as a slot
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integrated circuit (also known as IC, microcircuit, microchip, silicon chip, or chip) is a miniaturized electronic circuit (consisting mainly of semiconductor devices, as well as passive components) that has been manufactured in the surface of a
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Form factor may refer to:
  • Form factor (radiative transfer) or emissivity, the proportion of energy transmitted by that object which can be transferred to another object
  • Form factor (electronics), an alternating current waveform

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NVIDIA Corporation

Public (NASDAQ:  NVDA )
Founded 1993
Headquarters 2701 San Tomas Expressway
Santa Clara, California
USA

Key people Jen-Hsun Huang, Co-Founder, President and CEO
Industry Semiconductors- Specialized
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GeForce FX or "GeForce 5" series (codenamed NV30) is a line of graphics cards from the manufacturer NVIDIA.

Specifications

NVIDIA's GeForce FX series is the fifth generation in the GeForce line.
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Network Card

A 1990s Ethernet network interface controller card which connects to the motherboard via the now-obsolete ISA bus.

Connects to:
  • Motherboard via one of

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In computing, a storage area network (SAN) is an architecture to attach remote computer storage devices (such as disk arrays, tape libraries and optical jukeboxes) to servers in such a way that, to the operating system, the devices appear as locally attached.
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Modem (from modulate and demodulate) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information.
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personal computer (PC) is a computer whose original sales price, size, and capabilities make it useful for individuals.

It is unknown who coined the phrase with the intent of a small affordable computing device but John W.
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MITS Altair 8800 was a microcomputer design from 1975, based on the Intel 8080 CPU. Sold as a kit through Popular Electronics magazine, the designers intended to sell only a few hundred to hobbyists, and were surprised when they sold thousands in the first month.
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Apple II (sometimes written as Apple ][ or Apple //) was the first popular microcomputer manufactured by Apple. Its direct ancestor was the Apple I, a limited production circuit board computer for electronics hobbyists which pioneered many features that made the Apple
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Macintosh, commonly known as Mac, is a brand name which covers several lines of personal computers designed, developed, and marketed by Apple Inc. Named after the McIntosh variety of apple, the original Macintosh was released on January 24, 1984.
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Intel 8080
Central processing unit

An Intel C8080A processor.
Produced: mid 1974
Manufacturer: Intel
CPU Speeds: 2 MHz

Instruction Set: pre x86

Number of cores:
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The Zilog Z80 is an 8-bit microprocessor designed and sold by Zilog from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes.
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CP/M is an operating system originally created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc. Initially confined to single tasking on 8-bit processors and no more than 64 kilobytes of memory, later versions of CP/M added multi-user variations, and
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The S-100 bus, IEEE696-1983 (withdrawn), was an early computer bus designed in 1974 as a part of the Altair 8800, generally considered today to be the first personal computer (or at least the first "microcomputer", insofar as it was designed for hobbyists rather
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