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VESA Local Bus is an example of a local bus design.
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VESA and Local
By the time there was a strong market need for a bus of these speeds and capabilities, the VESA Local Bus and later PCI filled this niche and EISA vanished into obscurity.
For general desktop computer use it has been supplanted by later buses such as IBM Micro Channel, VESA Local Bus, Peripheral Component Interconnect and other successors.
The PCI Local Bus was first implemented in IBM PC compatibles, where it displaced the combination of ISA plus one VESA Local Bus as the bus configuration.
VESA ( Video Electronics Standards Association ) 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.
The VESA Local Bus was designed as a stopgap solution to the problem of the ISA bus's limited bandwidth.
When the Pentium processor arrived there were major differences in its bus design, and was not easily adaptable to a VESA Local Bus implementation.
Most PCs that used VESA Local Bus had only one or two VLB capable ISA slots from the 5 or 6 available ( thus 4 ISA slots generally were just that, ISA only ).
Despite these problems, the VESA Local Bus became very commonplace on later 486 motherboards, with a majority of later ( post 1993 ) 486-based systems featuring a VESA Local Bus video card.
PCI also displaced the VESA Local Bus in the remaining 486 market, with some of the last 80486 motherboards featuring PCI slots instead of VLB slots.
Compaq ) and then the VESA Local Bus Standard, were late 1980s expansion buses that were tied but not exclusive to the 80386 and 80486 CPU bus.
The PC clone market did not want to pay royalties to IBM in order to use this new technology, and for desktop machines vendors of PC-compatibles stayed largely with the 16-bit AT bus, ( embraced and renamed as ISA to avoid IBM's " AT " trademark ) and manual configuration, although the VESA Local Bus was briefly popular for Intel ' 486 machines.
VESA and is
Generalized Timing Formula ( GTF ) 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.
Similar to 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 (" graphics card ") of the device supports it.
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.
VESA (; Video Electronics Standards Association ) is an international standards body for computer graphics formed in 1988 by NEC Home Electronics, maker of the MultiSync monitor line, and eight video display adapter manufacturers: ATI Technologies, Genoa Systems, Orchid Technology, Renaissance GRX, STB Systems, Tecmar, Video 7 and Western Digital / Paradise Systems.
VESA BIOS Extensions ( VBE ) is a VESA standard, currently at version 3, that defines the interface that can be used by software to access compliant video boards at high resolutions and bit depths.
VESA Display Power Management Signaling ( or DPMS ) is a standard from the VESA consortium for managing the power supply of video monitors for computers through the graphics card e. g. ; shut off the monitor after the computer has been unused for some time ( idle ), to save power.
This is the case, for instance, with the VESA Local Bus which lacks the two least significant bits, limiting this bus to aligned 32-bit transfers.
The Modeline is based on the Generalized Timing Formula or the Coordinated Video Timings standards produced by VESA.
A synchronization signal is generated for LC shutter glasses worn by the viewer, using either a standard VESA Stereo plug to connect wired glasses or wireless emitters, or brief flashes of light on the viewing screen during the blanking interval.
DisplayPort is a digital display interface developed by the Video Electronics Standards Association ( VESA ).
VESA and example
In the event, the new EISA bus was itself a commercial failure beyond the high end: By the time the cost of implementing EISA was reduced to the extent that it would be implemented in most desktop PCs, the much cheaper VESA Local Bus had removed most of the need for it in desktop PCs ( though it remained common in servers due to for example the possibility of data corruption on hard disk drives attached to VLB controllers ), and Intel's PCI bus was just around the corner.
The most prominent example was the ELSA Revelator glasses, which worked exclusively in Nvidia cards through a proprietary interface based on VESA Stereo.
VESA and bus
* VESA Feature Connector ( VFC ), obsolete connector that was often present on older videocards, used as an 8-bit video bus to other devices
* VESA Advanced Feature Connector ( VAFC ), newer version of the above VFC that widens the 8-bit bus to either a 16-bit or 32-bit bus
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, 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.
0.099 seconds.