Video Graphics Array Driver Download Install Update
VGA was the last IBM graphics standard to which the majority of PC clone manufacturers conformed, making it the lowest common denominator that virtually all post PC graphics hardware can be expected to implement. Today, the VGA analog interface is used for high-definition video, including resolutions of p and higher. While the transmission bandwidth of VGA is high enough to support even higher resolution playback, there can be picture quality degradation depending on cable quality and length.
How discernible this degradation is depends on the individual's eyesight and the display, though it is more noticeable when switching to and from digital inputs like HDMI or DVI. The other color modes defaulted to standard EGA or CGA compatible palettes including the ability for programs to redefine the color EGA palette from a master color table , but could still be redefined if desired using VGA-specific programming. As well as the standard modes, VGA can be configured to emulate many of the modes of its predecessors EGA , CGA , and MDA , including their reduced global color palettes with particular pre-set colors chosen from the VGA palette for text and 4- or color, line modes and coarser text font grids.
Compatibility is almost full at BIOS level, but even at register level, a very high value of compatibility is reached. VGA is not directly compatible with the special IBM PCjr or HGC video modes, despite having sufficient resolution, color, refresh rate and memory capabilities; any emulation of these modes has to be performed in software instead.
The intended standard value for the horizontal frequency of VGA is exactly double the value used in the NTSC-M video system, as this made it much easier to offer optional TV-out solutions or external VGA-to-TV converter boxes at the time of VGA's development, a technique proposed by Zia Shlaimoun; it is also at least nominally twice that of CGA, which itself used broadcast-frequency monitors, essentially tunerless televisions with more direct signal inputs.
In this case, a In fact, CGA itself was further adrift as it could only scan lines per progressive frame, instead of All derived VGA timings i. However, only the standard modes, or modes that at least use almost exactly the same H-sync and V-sync timings as one of the standard modes, can be expected to work with the original lates and earlys VGA monitors.
The use of other timings may in fact damage such monitors and thus was usually avoided by software publishers. The same general layout applies, merely at a lower frequency, for the vertical timings. Total vertical sync and blanking time 1. This does not usually cause a problem as the porches are merely intended to act as blanked-video buffers offering a little overscan space between the active area and the sync pulse which triggers, in traditional CRT monitors, the phosphor beam deflection "flyback" to the upper or left hand side of the tube and thus can be safely overrun into by a certain amount when everything else is operating correctly.
The relationship between the front and back porches can also be altered within certain limits, which makes possible special features such as software-based image alignment with certain graphics cards centering the image within the monitor frame by adjusting the location of the active screen area between the horizontal and vertical porches, rather than relying wholly upon the adjustment range offered by the monitor's own controls which can sometimes be less than satisfactory.
This buffer zone is typically what is exploited to achieve higher active resolutions in the various custom screen modes, by deliberately reducing porch widths and using the freed-up scan time for active pixels instead. Should the detection fail, however, or the user cancel the high-quality graphics either temporarily with a keyboard shortcut, or permanently via a BIOS setting , the old standard mode is generally reasserted. The actual timings vary slightly from the defined standard.
Given the similarity of the frequency and line length, this may be due to typographical errors that were never detected or corrected; at the standard clock equal to Otherwise, if the spec were true, that would imply a faster Further examination of the other timing details e. This connector fits on the mounting tab of an ISA expansion card. An alternative method of connecting VGA devices that maintains very high signal quality even over extended cable runs is the BNC connector , typically used as a group of five connectors, one each for Red, Green, Blue, Horizontal Sync, and Vertical Sync.
With BNC, the coaxial wires are fully shielded end-to-end and through the interconnect so that no crosstalk or external interference is possible, easily doubling standard VGA's maximum reliable distance of 15 metres, and reaching metres with the aid of nothing more than a simple signal booster. However, BNC connectors are relatively large compared to the pin D-shell, and some attention is needed - vs the insertion of that single plug - to ensure each cable goes to the correct socket; although the core RGB lines are coloured appropriately, the sync wires can be various arbitrary colours yellow, grey, white, black and although standards do exist for these it is often unclear which is the correct arrangement at the point of connection and it can become a process of elimination.
Beyond around 50 metres, or 30 metres without any active amplification, cable capacitance can become a problem for the analogue signals, noticeably reducing horizontal image resolution and causing poor sync. Each cell may choose from one of 16 available colors for its foreground and eight colors for the background; the eight background colors allowed are the ones without the high-intensity bit set.
Each character may also be made to blink ; all that are set to blink will blink in unison. Like EGA, VGA supports having up to different simultaneous characters on screen, albeit in only 8 foreground colors, by rededicating one color bit as the highest bit of the character number. Users may define their own character set by loading a custom font onto the card. As character data is only eight bits wide on VGA, just as on all of its predecessors, there is usually a blank pixel column between any two horizontally adjacent glyphs.
However, some characters are normally made nine bits wide by repeating their last column instead of inserting a blank column, especially those defining horizontally connected IBM box-drawing characters. This functionality is hard-wired to the character numbers C0 hex to DF hex , where all horizontally connecting characters are found in code page and its most common derivatives.
VGA adapters usually support both monochrome and color modes, though the monochrome mode is almost never used, and support for the full set of MDA text mode attributes intense, underline is often missing. Black and white text on nearly all modern VGA adapters is drawn by using gray colored text on a black background in color mode. VGA monochrome monitors intended primarily for text were sold, but most of them will work at least adequately with a VGA adapter in color mode.
Occasionally, a faulty connection between a modern monitor and video card will cause the VGA part of the card to detect the monitor as monochrome; this will cause the BIOS and initial boot sequence to appear in greyscale. Usually, once the video card's drivers are loaded for example, by continuing to boot into the operating system , they will override this detection and the monitor will return to color.
Typically, these starting segments are:. Due to the use of different address mappings for different modes, it is possible to have a monochrome adapter i. At the beginning of the s, this was typically used to display Lotus spreadsheets in high-resolution text on a monochrome display and associated graphics on a low-resolution CGA display simultaneously. Many programmers also used such a setup with the monochrome card displaying debugging information while a program ran in graphics mode on the other card.
Cox and Microsoft's CodeView could work in a dual monitor setup. There were also DOS device drivers such as ox. CGA was able to display 16 fixed colors , and EGA extended this by using 16 palette registers , each containing a color value from a color palette. This works in graphics and text modes.
The signals from the EGA palette entries will drive a set of six signal lines on the EGA output, with two lines corresponding to one color off, dark, normal and bright, for red, green and blue. These color registers are by default set to match the 64 default EGA colors.
The values from these registers drive a DAC , which in turn drives three signal lines, one for red, green and blue. Because analog signals are used, a default VGA cable can carry a theoretically unlimited number of color values.
Like EGA uses the CGA color value to address a palette entry, the VGA hardware will also use the palette entries not directly as signal levels but as indexes to the color registers. Therefore, in the color modes, the color value from the RAM will reference a palette register and that palette register will select a color register. The corresponding VGA color register 0x14 is preset to 42,21,0, or aa, also and off cause brown.
In the color modes, the palette registers are ignored and the DAC is set to combine four 2-bit color values, one from each plane, into the original 8-bit-value.
The CPU interface combined the 4 planes in the exact same way a feature called "chain-4" so that the pixel appeared to the CPU as a packed 8-bit value. This color number is exactly which color register is used. Since the colors The other entries are 16 gray levels from black to white and 9 groups of 24 color values.
The remaining 8 entries were black see picture. There is a trade-off for extra complexity and performance loss in some types of graphics operations, but this is mitigated by other operations becoming faster in certain situations:. The highest resolution modes were only used in special, opt-in cases rather than as standard, especially where high line counts were involved. These modes were also outright incompatible with some monitors, producing display problems such as picture detail disappearing into overscan especially in the horizontal dimension , vertical roll, poor horizontal sync or even a complete lack of picture depending on the exact mode attempted.
Several companies produced VGA compatible graphic board models. From Wikipedia, the free encyclopedia. This article is about the computer display standard. For the pin video connector, see VGA connector. For a full list of display resolutions, see graphic display resolutions. For other uses, see VGA disambiguation. VGA compatible text mode. This article possibly contains original research. Please improve it by verifying the claims made and adding inline citations.
Statements consisting only of original research should be removed. November Learn how and when to remove this template message. Archived from the original on Archived from the original on 27 October Retrieved 7 November Graphics Programming Black Book.
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Video card VS. Video Graphics Array(VGA a popular display standard)
The VGA graphics adapter 5. It is the most basic display setup for Windows-based computers. It is a helpful utility software that enhances the performance of your display monitor. It improves the resolution of your screens and provides a way to further upgrade your video card. When set to default or factory settings, you can see in your Device Manager that your display monitor is set to standard VGA graphics monitor. It is one of the most indispensable parts of any computer setup. Basic as it seems, standard VGA graphics adapters can perform well when properly installed with a video driver. It can well display resolutions of x, x, x, or x screen resolutions. I can also display colors in 4, 16, and colors, and even in monochrome. Are we on twitter? I need to update this driver. I will use the program to fix a system error which in any event is not identifying the card properly.