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80-426: DVI devices manufactured as DVI-I have support for analog connections, and are compatible with the analog VGA interface by including VGA pins, while DVI-D devices are digital-only. This compatibility, along with other advantages, led to its widespread acceptance over competing digital display standards Plug and Display (P&D) and Digital Flat Panel (DFP). Although DVI is predominantly associated with computers, it

160-478: A gross bit rate that is 10 times the frequency of the TMDS clock. In each TMDS clock period there is a 10-bit symbol per TMDS data pair representing 8-bits of pixel color. In single link mode each set of three 10-bit symbols represents one 24-bit pixel, while in dual link mode each set of six 10-bit symbols either represents two 24-bit pixels or one pixel of up to 48-bit color depth . The specification document allows

240-567: A 35-pin MicroCross connector similar to EVC; the analog audio and video input lines from EVC were repurposed to carry digital video for P&D. Because P&D was a physically large, expensive connector, a consortium of companies developed the DFP standard (1999), which was focused solely on digital video transmission using a 20-pin micro ribbon connector and omitted the analog video and data capabilities of P&D. DVI instead chose to strip just

320-467: A DVI-D source because HDMI and DVI-D both define an overlapping minimum set of supported resolutions and frame buffer formats. Some DVI-D sources use non-standard extensions to output HDMI signals including audio (e.g. ATI 3000-series and NVIDIA GTX 200-series ). Some multimedia displays use a DVI to HDMI adapter to input the HDMI signal with audio. Exact capabilities vary by video card specifications. In

400-520: A console. This also helps to make up for lack of titles at the launch of new systems, as users can pull from the previous console's library of games while developers transition to the new hardware. Moreover, studies in the mid-1990s found that even consumers who never play older games after purchasing a new system consider backward compatibility a highly desirable feature, valuing the mere ability to continue to play an existing collection of games even if they choose never to do so. Backward compatibility with

480-406: A factor with low-quality or overly long cables. Solutions include shielded cables, cables that include a separate internal coaxial cable for each color signal, and "broken out" cables utilizing a separate coaxial cable with a BNC connector for each color signal. BNC breakout cables typically use five connectors, one each for Red, Green, Blue, Horizontal Sync, and Vertical Sync, and do not include

560-409: A fixed line scan (H-scan) rate – "multisync" monitors being, at the time, expensive rarities – and so the vertical/frame (V-scan) refresh rate had to be reduced in order to accommodate them, which increased visible flicker and thus eye strain . For example, the highest 800 × 600 mode, being otherwise based on the matching SVGA resolution (with 628 total lines), reduced

640-491: A graphical boot screen, while text-mode boot uses 720 × 400 @ 70 Hz. This convention has been eroded in recent years, however, with POST and BIOS screens moving to higher resolutions, taking advantage of EDID data to match the resolution to a connected monitor. 640 × 480 @ 60 Hz is the default Windows graphics mode (usually with 16 colors), up to Windows 2000. It remains an option in XP and later versions via

720-448: A large frequency range. One benefit of DVI over other interfaces is that it is relatively straightforward to transform the signal from the digital domain into the analog domain using a video DAC , as both clock and synchronization signals are transmitted. Fixed frequency interfaces, like DisplayPort , need to reconstruct the clock from the transmitted data. The DVI specification includes signaling for reducing power consumption. Similar to

800-456: 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. Several debuggers, like Borland's Turbo Debugger , D86 and Microsoft's CodeView could work in a dual monitor setup. Either Turbo Debugger or CodeView could be used to debug Windows. There were also device drivers such as ox.sys , which implemented

880-525: A main VGA chip, which eliminated several other chips in previous graphics adapters, so VGA only additionally required external video RAM and timing crystals . This small part count allowed IBM to include VGA directly on the PS/2 motherboard, in contrast to prior IBM PC models – PC , PC/XT , and PC AT  – which required a separate display adapter installed in a slot in order to connect

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960-447: A male DVI-I to a female DVI-D. It is possible, however, to join a male DVI-D connector with a female DVI-I connector. DVI is the only widespread video standard that includes analog and digital transmission in the same connector. Competing standards are exclusively digital: these include a system using low-voltage differential signaling ( LVDS ), known by its proprietary names FPD-Link (flat-panel display) and FLATLINK; and its successors,

1040-483: A manufacturer decides to stop supporting older hardware. Classic video games are a common example used when discussing the value of supporting older software. The cultural impact of video games is a large part of their continued success, and some believe ignoring backward compatibility would cause these titles to disappear. Backward compatibility also acts as a selling point for new hardware, as an existing player base can more affordably upgrade to subsequent generations of

1120-418: A monitor. The term "array" rather than "adapter" in the name denoted that it was not a complete independent expansion device, but a single component that could be integrated into a system. Unlike the graphics adapters that preceded it ( MDA , CGA , EGA and many third-party options) there was initially no discrete VGA card released by IBM. The first commercial implementation of VGA was a built-in component of

1200-512: A much wider range of resolutions and refresh rates at arbitrary sync frequencies and pixel clock rates. For the most common VGA mode ( 640 × 480 , 60 Hz, non-interlaced ), the horizontal timings can be found in the HP Super VGA Display Installation Guide and in other places. 640 × 400 @ 70 Hz is traditionally the video mode used for booting VGA-compatible x86 personal computers that show

1280-659: A preferred mode or native resolution . Each mode is a set of timing values that define the duration and frequency of the horizontal/vertical sync, the positioning of the active display area, the horizontal resolution, vertical resolution, and refresh rate. The maximum length recommended for DVI cables is not included in the specification, since it is dependent on the TMDS clock frequency. In general, cable lengths up to 4.5 metres (15 ft) will work for display resolutions up to 1920 × 1200. Longer cables up to 15 metres (49 ft) in length can be used with display resolutions 1280 × 1024 or lower. For greater distances,

1360-418: A receiver can fully differentiate between active and control regions. When DVI was designed, most computer monitors were still of the cathode-ray tube type that require analog video synchronization signals. The timing of the digital synchronization signals matches the equivalent analog ones, so the process of transforming DVI to and from an analog signal does not require extra (high-speed) memory, expensive at

1440-639: A serial interface simulation on the monochrome display and, for example, allowed the user to receive crash messages from debugging versions of Windows without using an actual serial terminal. It is also possible to use the "MODE MONO" command at the command prompt to redirect the output to the monochrome display. When a monochrome adapter was not present, it was possible to use the 0xB000–0xB7FF address space as additional memory for other programs. A VGA-capable PCI / PCIe graphics card can provide legacy VGA registers in its PCI configuration space , which may be remapped by BIOS or operating system . "Unchaining"

1520-484: A single transmitter with a TMDS clock up to 165 MHz that supports resolutions up to 1920 × 1200 at 60 Hz. Dual link DVI adds six pins, at the center of the connector, for a second transmitter increasing the bandwidth and supporting resolutions up to 2560 × 1600 at 60 Hz. A connector with these additional pins is sometimes referred to as DVI-DL (dual link). Dual link should not be confused with dual display (also known as dual head ), which

1600-422: A video source with DVI-I through the use of a passive adapter. Since the analog pins are directly compatible with VGA signaling, passive adapters are simple and cheap to produce, providing a cost-effective solution to support VGA on DVI. The long flat pin on a DVI-I connector is wider than the same pin on a DVI-D connector, so even if the four analog pins were manually removed, it still wouldn't be possible to connect

1680-605: Is backward compatible with the EGA and CGA adapters, but supports extra bit depth for the palette when in these modes. For instance, when in EGA 16-color modes, VGA offers 16 palette registers, and in 256-color modes, it offers 256 registers. Each palette register contain a 3×6 bit RGB value, selecting a color from the 18-bit gamut of the DAC . These color registers are initialized to default values IBM expected to be most useful for each mode. For instance, EGA 16-color modes initialize to

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1760-486: Is a VESA standard which can easily be calculated with the Linux gtf utility. Coordinated Video Timings -Reduced Blanking (CVT-RB) is a VESA standard which offers reduced horizontal and vertical blanking for non-CRT based displays. One of the purposes of DVI stream encoding is to provide a DC-balanced output that reduces decoding errors. This goal is achieved by using 10-bit symbols for 8-bit or less characters and using

1840-427: Is a configuration consisting of a single computer connected to two monitors, sometimes using a DMS-59 connector for two single link DVI connections. In addition to digital, some DVI connectors also have pins that pass an analog signal, which can be used to connect an analog monitor. The analog pins are the four that surround the flat blade on a DVI-I or DVI-A connector. A VGA monitor, for example, can be connected to

1920-479: Is a general notion of interoperation between software pieces that will not produce any errors when its functionality is invoked via API . The software is considered stable when its API that is used to invoke functions is stable across different versions. In operating systems, upgrades to newer versions are said to be backward compatible if executables and other files from the previous versions will work as usual. In compilers , backward compatibility may refer to

2000-417: Is a newer digital audio/video interface developed and promoted by the consumer electronics industry . DVI and HDMI have the same electrical specifications for their TMDS and VESA/DDC twisted pairs. However HDMI and DVI differ in several key ways. To promote interoperability between DVI-D and HDMI devices, HDMI source components and displays support DVI-D signaling. For example, an HDMI display can be driven by

2080-436: Is also provide this port-mapped I/O segment: Due to the use of different address mappings for different modes, it is possible to have a monochrome adapter (i.e. MDA or Hercules ) and a color adapter such as the VGA, EGA , or CGA installed in the same machine. At the beginning of the 1980s, this was typically used to display Lotus 1-2-3 spreadsheets in high-resolution text on a monochrome display and associated graphics on

2160-447: Is encoded using 8b/10b encoding . DVI does not use packetization , but rather transmits the pixel data as if it were a rasterized analog video signal. As such, the complete frame is drawn during each vertical refresh period. The full active area of each frame is always transmitted without compression. Video modes typically use horizontal and vertical refresh timings that are compatible with cathode-ray tube (CRT) displays, though this

2240-498: Is not a requirement. In single link mode, the maximum TMDS clock frequency is 165 MHz, which supports a maximum resolution of 2.75  megapixels (including blanking interval ) at 60 Hz refresh. For practical purposes, this allows a maximum 16:10 screen resolution of 1920 × 1200 at 60 Hz. To support higher-resolution display devices, the DVI specification contains a provision for dual link . Dual link DVI doubles

2320-534: Is particularly important in computer instruction set architectures , two of the most successful being the IBM 360 / 370 / 390 / Zseries families of mainframes, and the Intel x86 family of microprocessors . IBM announced the first 360 models in 1964 and has continued to update the series ever since, with migration over the decades from 32-bit register/24-bit addresses to 64-bit registers and addresses. Intel announced

2400-425: Is sometimes called " breaking " backward compatibility. Such breaking usually incurs various types of costs, such as switching cost . A complementary concept is forward compatibility ; a design that is forward-compatible usually has a roadmap for compatibility with future standards and products. A simple example of both backward and forward compatibility is the introduction of FM radio in stereo . FM radio

2480-407: Is sometimes seen is 80 × 30 or 80 × 60 , using an 8 × 16 or 8 × 8 font and an effective 640 × 480 pixel display, which trades use of the more flickery 60 Hz mode for an additional 5 or 10 lines of text and square character blocks (or, at 80 × 30 , square half-blocks). Unlike the cards that preceded it, which used binary TTL signals to interface with a monitor (and also composite , in

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2560-788: Is sometimes used in other consumer electronics such as television sets and DVD players . An earlier attempt to promulgate an updated standard to the analog VGA connector was made by the Video Electronics Standards Association (VESA) in 1994 and 1995, with the Enhanced Video Connector (EVC), which was intended to consolidate cables between the computer and monitor. EVC used a 35-pin Molex MicroCross connector and carried analog video (input and output), analog stereo audio (input and output), and data (via USB and FireWire ). At

2640-417: Is to keep compatibility with the previous VGA cables and connectors . VGA pins for HSync, Vsync and three video channels are available in both DVI-I or DVI-A (but not DVI-D) connectors and are electrically compatible, while pins for DDC (clock and data) and 5 V power and ground are kept in all DVI connectors. Thus, a passive adapter can interface between DVI-I or DVI-A (but not DVI-D) and VGA connectors. HDMI

2720-424: Is transported using multiple TMDS twisted pairs . At the electrical level, these pairs are highly resistant to electrical noise and other forms of analog distortion . A single link DVI connection has four TMDS pairs. Three data pairs carry their designated 8-bit RGB component (red, green, or blue) of the video signal for a total of 24 bits per pixel . The fourth pair carries the TMDS clock. The binary data

2800-616: The LVDS Display Interface (LDI) and OpenLDI . Some DVD players , HDTV sets, and video projectors have DVI connectors that transmit an encrypted signal for copy protection using the High-bandwidth Digital Content Protection (HDCP) protocol. Computers can be connected to HDTV sets over DVI, but the graphics card must support HDCP to play content protected by digital rights management (DRM). Generalized Timing Formula (GTF)

2880-508: 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. It is also at least nominally twice that of CGA, which also supported composite monitors . All derived VGA timings (i.e. those which use the master 25.175 and 28.322 MHz crystals and, to a lesser extent, the nominal 31.469 kHz line rate) can be varied by software that bypasses

2960-739: The computer display standard , the 15-pin D-subminiature VGA connector , or the 640 × 480 resolution characteristic of the VGA hardware. VGA was the last IBM graphics standard to which the majority of IBM PC compatible computer manufacturers conformed, making it the lowest common denominator that virtually all post-1990 PC graphics hardware can be expected to implement. VGA was adapted into many extended forms by third parties, collectively known as Super VGA , then gave way to custom graphics processing units which, in addition to their proprietary interfaces and capabilities, continue to implement common VGA graphics modes and interfaces to

3040-530: The "VGA" graphics mode remained a compatibility option for PC operating systems. Nonstandard display modes can be implemented, with horizontal resolutions of: And heights of: For example, high resolution modes with square pixels are available at 768 × 576 or 704 × 528 in 16 colors, or medium-low resolution at 320 × 240 with 256 colors. Alternatively, extended resolution is available with "fat" pixels and 256 colors using, e.g. 400 × 600 (50 Hz) or 360 × 480 (60 Hz), and "thin" pixels, 16 colors and

3120-639: The 256 KB VGA memory into four separate "planes" makes VGA's 256 KB of RAM available in 256-color modes. 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: Software such as Fractint , Xlib and ColoRIX also supported tweaked 256-color modes on standard adaptors using freely-combinable widths of 256, 320, and 360 pixels and heights of 200, 240 and 256 (or 400, 480 and 512) lines, extending still further to 384 or 400 pixel columns and 576 or 600 (or 288, 300). However, 320 × 240

3200-576: The 256-color palette. The CPU interface combines the 4 planes in the same way, a feature called "chain-4", so that each pixel appears to the CPU as a packed 8-bit value representing the palette index. The video memory of the VGA is mapped to the PC's memory via a window in the range between segments 0xA0000 and 0xBFFFF in the PC's real mode address space (A000:0000 and B000:FFFF in segment:offset notation). Typically, these starting segments are: A typical VGA card

3280-514: The 70 Hz refresh rate with e.g. 736 × 410 mode. "Narrow" modes such as 256 × 224 tend to preserve the same pixel ratio as in e.g. 320 × 240 mode unless the monitor is adjusted to stretch the image out to fill the screen, as they are derived simply by masking down the wider mode instead of altering pixel or line timings, but can be useful for reducing memory requirements and pixel addressing calculations for arcade game conversions or console emulators. The PC version of Pinball Fantasies has

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3360-553: The DVI connector includes pins for the display data channel (DDC), which allows the graphics adapter to read the monitor's extended display identification data (EDID). When a source and display using the DDC2 revision are connected, the source first queries the display's capabilities by reading the monitor EDID block over an I²C link. The EDID block contains the display's identification, color characteristics (such as gamma value), and table of supported video modes. The table can designate

3440-848: The IBM PS/2, in which it was accompanied by 256 KB of video RAM, and a new DE-15 connector replacing the DE-9 used by previous graphics adapters. IBM later released the standalone IBM PS/2 Display Adapter , which utilized the VGA but could be added to machines that did not have it built in. The VGA supports all graphics modes supported by the MDA, CGA and EGA cards, as well as multiple new modes. The 640 × 480 16-color and 320 × 200 256-color modes had fully redefinable palettes, with each entry selected from an 18-bit (262,144-color) gamut. The other modes defaulted to standard EGA or CGA compatible palettes and instructions, but still permitted remapping of

3520-609: The VGA firmware interface and communicates directly with the VGA hardware, as many MS-DOS based games did. 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 late-1980s and early-1990s VGA monitors. The use of other timings may in fact damage such monitors and thus was usually avoided by software publishers. Third-party "multisync" CRT monitors were more flexible, and in combination with "super EGA", VGA, and later SVGA graphics cards using extended modes, could display

3600-471: The ability of a compiler for a newer version of the language to accept source code of programs or data that worked under the previous version. A data format is said to be backward compatible when a newer version of the program can open it without errors just like its predecessor. There are several incentives for a company to implement backward compatibility. Backward compatibility can be used to preserve older software that would have otherwise been lost when

3680-576: The analog VESA display power management signaling (DPMS) standard, a connected device can turn a monitor off when the connected device is powered down, or programmatically if the display controller of the device supports it. Devices with this capability can also attain Energy Star certification. The analog section of the DVI specification document is brief and points to other specifications like VESA VSIS for electrical characteristics and GTFS for timing information. The motivation for including analog

3760-566: The best connectivity options moving forward. In our opinion, DisplayPort 1.2 is the future interface for PC monitors, along with HDMI 1.4a for TV connectivity". VGA Video Graphics Array ( VGA ) is a video display controller and accompanying de facto graphics standard, first introduced with the IBM PS/2 line of computers in 1987, which became ubiquitous in the IBM PC compatible industry within three years. The term can now refer to

3840-423: The boot menu "low resolution video" option and per-application compatibility mode settings, despite newer versions of Windows now defaulting to 1024 × 768 and generally not allowing any resolution below 800 × 600 to be set. The need for such a low-quality, universally compatible fallback has diminished since the turn of the millennium, as VGA-signalling-standard screens or adaptors unable to show anything beyond

3920-463: The case of the CGA), the VGA introduced a video interface using pure analog RGB signals , with a range of 0.7 volts peak-to-peak max. In conjunction with a 18-bit RAMDAC (6-bit per RGB channel), this produced a color gamut of 262,144 colors. The original VGA specifications follow: The intended standard value for the horizontal frequency of VGA's 640 × 480 mode is exactly double the value used in

4000-511: The data and the clock to not be aligned. However, as the ratio between the TMDS clock and gross bit rate per TMDS pair is fixed at 1:10, the unknown alignment is kept over time. The receiver must recover the bits on the stream using any of the techniques of clock/data recovery to find the correct symbol boundary. The DVI specification allows the TMDS clock to vary between 25 MHz and 165 MHz. This 1:6.6 ratio can make clock recovery difficult, as phase-locked loops , if used, need to work over

4080-466: The data functions from P&D, using a 29-pin MicroCross connector to carry digital and analog video. Critically, DVI allows dual-link TMDS signals, meaning it supports higher resolutions than the single-link P&D and DFP connectors, which led to its successful adoption as an industry standard. Compatibility of DVI with P&D and DFP is accomplished typically through passive adapters that provide appropriate physical interfaces, as all three standards use

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4160-512: The default CGA 16-color palette, and the 256-color mode initializes to a palette consisting of 16 CGA colors, 16 grey shades, and then 216 colors chosen by IBM to fit expected use cases. After initialization they can be redefined at any time without altering the contents of video RAM, permitting palette cycling . In the 256-color modes, the DAC is set to combine four 2-bit color values, one from each plane, into an 8-bit-value representing an index into

4240-468: The extra bits for the DC balancing. Like other ways of transmitting video, there are two different regions: the active region, where pixel data is sent, and the control region, where synchronization signals are sent. The active region is encoded using transition-minimized differential signaling , where the control region is encoded with a fixed 8b/10b encoding . As the two schemes yield different 10-bit symbols,

4320-513: The first Intel 8086 / 8088 processors in 1978, again with migrations over the decades from 16-bit to 64-bit. (The 8086/8088, in turn, were designed with easy machine-translatability of programs written for its predecessor in mind, although they were not instruction-set compatible with the 8-bit Intel 8080 processor of 1974. The Zilog Z80 , however, was fully backward compatible with the Intel 8080.) Fully backward compatible processors can process

4400-557: The horizontal dimension), vertical roll, poor horizontal sync or even a complete lack of picture depending on the exact mode attempted. Due to these potential issues, most VGA tweaks used in commercial products were limited to more standards-compliant, "monitor-safe" combinations, such as 320 × 240 (square pixels, three video pages, 60 Hz), 320 × 400 (double resolution, two video pages, 70 Hz), and 360 × 480 (highest resolution compatible with both standard VGA monitors and cards, one video page, 60 Hz) in 256 colors, or double

4480-443: The horizontal resolution in 16-color mode. Backward compatibility In telecommunications and computing , backward compatibility (or backwards compatibility ) is a property of an operating system , software, real-world product, or technology that allows for interoperability with an older legacy system , or with input designed for such a system. Modifying a system in a way that does not allow backward compatibility

4560-615: The main CPU for PS1 mode or upclocking itself to offload I/O in PS2 mode. This coprocessor was replaced with a PowerPC -based processor in later systems to serve the same functions, emulating the PS1 CPU core. Such an approach can backfire, though, as was the case of the Super Nintendo Entertainment System (Super NES). It opted for the more peculiar 65C816 CPU over the more popular 16-bit microprocessors on

4640-450: The mid 1990s, a 640 × 480 ×16 graphics mode using the VGA memory and register specifications was expected by operating systems such as Windows 95 and OS/2 Warp 3.0 , which provided no support for lower resolutions or bit depths, or support for other memory or register layouts without additional drivers. Well into the 2000s, even after the VESA standard for graphics cards became commonplace,

4720-803: The monitor. The 400-line signal was the same as the standard 80 × 25 text mode, which meant that pressing Esc to return to text mode didn't change the frequency of the video signal, and thus the monitor did not have to resynchronize (which could otherwise have taken several seconds). The standard VGA monitor interface is a 15-pin D-subminiature connector in the "E" shell, variously referred to as "DE-15", "HD-15" and erroneously "DB-15(HD)". All VGA connectors carry analog RGBHV (red, green, blue, horizontal sync , vertical sync ) video signals. Modern connectors also include VESA DDC pins, for identifying attached display devices. Because VGA uses low-voltage analog signals, signal degradation becomes

4800-431: The new system. Because of this, several console manufacturers phased out backward compatibility towards the end of the console generation in order to reduce cost and briefly reinvigorate sales before the arrival of newer hardware. It is possible to bypass some of these hardware costs. For instance, earlier PlayStation 2 (PS2) systems used the core of the original PlayStation (PS1) CPU as a dual-purpose processor, either as

4880-492: The newest generation of consoles such as PlayStation 5 and Xbox Series X/S also support this feature. A large part of the success and implementation of this feature is that the hardware within newer generation consoles is both powerful and similar enough to legacy systems that older titles can be broken down and re-configured to run on the Xbox One. This program has proven incredibly popular with Xbox players and goes against

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4960-553: The number of TMDS data pairs, effectively doubling the video bandwidth, which allows higher resolutions up to 2560 × 1600 at 60 Hz or higher refresh rates for lower resolutions. For backward compatibility with displays using analog VGA signals, some of the contacts in the DVI connector carry the analog VGA signals. To ensure a basic level of interoperability, DVI compliant devices are required to support one baseline display mode , "low pixel format" (640 × 480 at 60 Hz). Like modern analog VGA connectors ,

5040-421: The option to use non-standard modes "high res" modes, such as 640 × 350 , allowing it to display a larger portion of the pinball table on screen. VGA also implements several text modes: As with the pixel-based graphics modes, additional text modes are possible by programming the VGA correctly, with an overall maximum of about 100 × 80 cells and an active area spanning about 88 × 64 cells. One variant that

5120-497: The original PlayStation (PS) software discs and peripherals is considered to have been a key selling point for the PlayStation 2 (PS2) during its early months on the market. Despite not being included at launch, Microsoft slowly incorporated backward compatibility for select titles on the Xbox One several years into its product life cycle. Players have racked up over a billion hours with backward-compatible games on Xbox, and

5200-423: The original resolutions have become increasingly rare. 320 × 200 at 70 Hz was the most common mode for early 1990s PC games, with pixel-doubling and line-doubling performed in hardware to present a 640 × 400 at 70 Hz signal to the monitor. The Windows 95/98/Me LOGO.SYS boot-up image was 320 × 400 resolution, displayed with pixel-doubling to present a 640 × 400 at 70 Hz signal to

5280-408: The other signal lines of the VGA interface. With BNC, the coaxial wires are fully shielded end-to-end and through the interconnect so that virtually no crosstalk and very little external interference can occur. The use of BNC RGB video cables predates VGA in other markets and industries. The VGA color system uses register-based palettes to map colors in various bit depths to its 18-bit output gamut. It

5360-503: The palette with VGA-specific commands. The 640 × 480 resolution (at 256 colors rather than 16) was originally used by IBM in PGC graphics (which VGA offers no backward compatibility for) but did not see wide adoption until VGA was introduced. As the VGA began to be cloned in great quantities by manufacturers who added ever-increasing capabilities, its 640 × 480 , 16-color mode became the de facto lowest common denominator of graphics cards. By

5440-468: The present day. The VGA analog interface standard has been extended to support resolutions of up to 2048 × 1536 for general usage, with specialized applications improving it further still. The color palette random access memory (RAM) and its corresponding digital-to-analog converter (DAC) were integrated into one chip (the RAMDAC ) and the cathode-ray tube controller ( CRTC ) was integrated into

5520-423: The product that may lead to longer time to market , technological hindrances, and slowing innovation; and increased expectations from users in terms of compatibility. It also introduces the risk that developers will favor developing games that are compatible with both the old and new systems, since this gives them a larger base of potential buyers, resulting in a dearth of software which uses the advanced features of

5600-424: The recent trend of studio-made remasters of classic titles, creating what some believe to be an important shift in console makers' strategies. The monetary costs of supporting old software is considered a large drawback to the usage of backward compatibility. The associated costs of backward compatibility are a larger bill of materials if hardware is required to support the legacy systems; increased complexity of

5680-483: The refresh rate from 60 Hz to about 50 Hz (and 832 × 624 , the theoretical maximum resolution achievable with 256 KB at 16 colors, would have reduced it to about 48 Hz, barely higher than the rate at which XGA monitors employed a double-frequency interlacing technique to mitigate full-frame flicker). These modes were also outright incompatible with some monitors, producing display problems such as picture detail disappearing into overscan (especially in

5760-818: The reverse scenario, a DVI display that lacks optional support for HDCP might be unable to display protected content even though it is otherwise compatible with the HDMI source. Features specific to HDMI such as remote control, audio transport, xvYCC and deep color are not usable in devices that support only DVI signals. HDCP compatibility between source and destination devices is subject to manufacturer specifications for each device. In December 2010, Intel , AMD , and several computer and display manufacturers announced they would stop supporting DVI-I, VGA and LVDS -technologies from 2013/2015, and instead speed up adoption of DisplayPort and HDMI. They also stated: "Legacy interfaces such as VGA, DVI and LVDS have not kept pace, and newer standards such as DisplayPort and HDMI clearly provide

5840-494: The same binary executable software instructions as their predecessors, allowing the use of a newer processor without having to acquire new applications or operating systems . Similarly, the success of the Wi-Fi digital communication standard is attributed to its broad forward and backward compatibility; it became more popular than other standards that were not backward compatible. In software development, backward compatibility

5920-458: The same DDC/EDID handshaking protocols and TMDS digital video signals. DVI made its way into products starting in 1999. One of the first DVI monitors was Apple's original Cinema Display , which launched in 1999. DVI's digital video transmission format is based on panelLink , a serial format developed by Silicon Image that utilizes a high-speed serial link called transition minimized differential signaling (TMDS). Digital video pixel data

6000-547: The same time, with the increasing availability of digital flat-panel displays, the priority shifted to digital video transmission, which would remove the extra analog/digital conversion steps required for VGA and EVC; the EVC connector was reused by VESA, which released the Plug & Display (P&D) standard in 1997. P&D offered single-link TMDS digital video with, as an option, analog video output and data (USB and FireWire), using

6080-444: The sum signal while ignoring the difference signal, which is necessary only for separating the audio channels. Stereo FM receivers can receive a mono signal and decode it without the need for a second signal, and they can separate a sum signal to left and right channels if both sum and difference signals are received. Without the requirement for backward compatibility, a simpler method could have been chosen. Full backward compatibility

6160-461: The time. HDCP is an extra layer that transforms the 10-bit symbols before transmitting. Only after correct authorization can the receiver undo the HDCP encryption. Control regions are not encrypted in order to let the receiver know when the active region starts. DVI provide one TMDS clock pair and 3 TMDS data pairs in single link mode or 6 TMDS data pairs in dual link mode. TMDS data pairs operate at

6240-409: The use of a DVI booster—a signal repeater which may use an external power supply—is recommended to help mitigate signal degradation. The DVI connector on a device is given one of three names, depending on which signals it implements: Most DVI connector types—the exception is DVI-A—have pins that pass digital video signals. These come in two varieties: single link and dual link. Single link DVI employs

6320-410: Was initially mono , with only one audio channel represented by one signal . With the introduction of two-channel stereo FM radio, many listeners had only mono FM receivers. Forward compatibility for mono receivers with stereo signals was achieved by sending the sum of both left and right audio channels in one signal and the difference in another signal. That allows mono FM receivers to receive and decode

6400-510: Was the best known and most frequently used, as it offered a standard 40-column resolution and 4:3 aspect ratio with square pixels. " 320 × 240  × 8" resolution was commonly called Mode X , the name used by Michael Abrash when he presented the resolution in Dr. Dobb's Journal . The highest resolution modes were only used in special, opt-in cases rather than as standard, especially where high line counts were involved. Standard VGA monitors had

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