The Feature connector was an internal connector

Electrical connector

An electrical connector is an electro-mechanical device for joining electrical circuits as an interface using a mechanical assembly. The connection may be temporary, as for portable equipment, require a tool for assembly and removal, or serve as a permanent electrical joint between two wires or...

 found mostly in some older VESA Local Bus

VESA Local Bus

The VESA Local Bus was mostly used in personal computers. VESA Local Bus worked alongside the ISA bus; it acted as a high-speed conduit for memory-mapped I/O and DMA, while the ISA bus handled interrupts and port-mapped I/O.-Historical overview:In the early 1990s, the I/O bandwidth of...

, ISA

Industry Standard Architecture

Industry Standard Architecture is a computer bus standard for IBM PC compatible computers introduced with the IBM Personal Computer to support its Intel 8088 microprocessor's 8-bit external data bus and extended to 16 bits for the IBM Personal Computer/AT's Intel 80286 processor...

 and PCI

Peripheral Component Interconnect

Conventional PCI is a computer bus for attaching hardware devices in a computer...

 graphics cards, but also on some early AGP

Accelerated Graphics Port

The Accelerated Graphics Port is a high-speed point-to-point channel for attaching a video card to a computer's motherboard, primarily to assist in the acceleration of 3D computer graphics. Since 2004 AGP has been progressively phased out in favor of PCI Express...

 ones.

It was intended for use by devices which needed to exchange large amounts of data with the graphics card without hogging a computer system's CPU

Central processing unit

The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

 or data bus, such as TV tuner card

TV tuner card

A TV tuner card is a kind of television tuner that allows television signals to be received by a computer. Most TV tuners also function as video capture cards, allowing them to record television programs onto a hard disk much like the Tivo digital video recorder does.-Variants: The interfaces for...

s, video capture cards, MPEG video decoders, first generation 3D graphic accelerator cards and the such.

Several standard existed for feature connectors, depending on the bus and graphics card type. Most of them were simply an 8, 16 or 32-bit

Bit

A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...

 wide internal connector, transferring data from and to the graphics card to another device, bypassing the system's CPU and memory completely.

Their speeds often far exceeded the speed of normal ISA or even early PCI buses, e.g. 40 MByte/s for a standard ISA-based SVGA

Super Video Graphics Array

Super Video Graphics Array or Ultra Video Graphics Array, almost always abbreviated to Super VGA, Ultra VGA or just SVGA or UVGA is a broad term that covers a wide range of computer display standards....

, up to 150 MByte/s for a PCI or VESA-based one, while the standard 16 bit ISA bus ran at ~5.3 MByte/s and the VESA bus at up to 160 MByte/s bandwidth. The Feature connector bandwidths were far beyond the capabilities of e.g. a 386

Intel 80386

The Intel 80386, also known as the i386, or just 386, was a 32-bit microprocessor introduced by Intel in 1985. The first versions had 275,000 transistors and were used as the central processing unit of many workstations and high-end personal computers of the time...

, 486

Intel 80486

The Intel 80486 microprocessor was a higher performance follow up on the Intel 80386. Introduced in 1989, it was the first tightly pipelined x86 design as well as the first x86 chip to use more than a million transistors, due to a large on-chip cache and an integrated floating point unit...

 and barely handled by an early Pentium.

Depending on the implementation, it could be uni or bi-directional, and carry analog

Analog television

Analog television is the analog transmission that involves the broadcasting of encoded analog audio and analog video signal: one in which the message conveyed by the broadcast signal is a function of deliberate variations in the amplitude and/or frequency of the signal...

 color information as well as data. Unlike analog overlay devices however, a feature connector carried mainly data

Data

The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...

 and essentially allowed an expansion card

Expansion card

The expansion card in computing is a printed circuit board that can be inserted into an expansion slot of a computer motherboard or backplane to add functionality to a computer system via the expansion bus.One edge of the expansion card holds the contacts that fit exactly into the slot...

 to access the graphics card Video RAM directly, although directing this data stream to the system's CPU and RAM was not always possible, limiting its usefulness mainly to display purposes.

Although its use rapidly declined after the introduction of the faster AGP internal bus, it was, at its time, the only feasible way to connect certain types of graphics-intensive devices to an average computing system without exceeding the available CPU power and memory bandwidth, and without the disadvantages and limitations of a purely analog overlay.

The idea of accessing a video card's memory directly has recently resurfaced with the introduction of the Scalable Link Interface

Scalable Link Interface

Scalable Link Interface is a brand name for a multi-GPU solution developed by NVIDIA for linking two or more video cards together to produce a single output...

 (SLI) technology, although this technology is aimed at connecting two equally powered and complete graphic cards in order to produce a single, increased performance visual output, and not e.g. directly interfacing TV tuner cards.

External links

• Definition of VESA Advanced feature connection at thefreedictionary.com
• Definition of VGA feature connection at thefreedictionary.com
• AMC, an ATI extension of the Feature Connector