IBM Monochrome Display Adapter

Monochrome Display Adapter (Abbreviation: MDA ) denotes the non -graphics display standard of the first IBM PC in the year 1981.

MDA only supports text display with 25 lines x 80 characters at a for that time relatively high resolution of 720 × 350 pixels. The characters are the 9 × 14 pixels, making the letters looked less blocky and the line spacing were larger than on other computers of that time who used usually only 7 or 8 × 8 × 8 pixels per character. In addition, the MDA, characters allowed in two brightness levels, underlined, or inverse ( dark on light ) display; colored illustration on the other hand was not possible. MDA is also the oldest and first " graphic " standard for PCs, IBM originally used but neither the name Monochrome Display Adapter or MDA. Responsible for the entire presentation was a chip called 6845 by Motorola. This chip is generated using the necessary peripheral components TTL signal to the monitor.

MDA monitors that have been used in the office as it is a eye-pleasing, ie Razor sharp and relatively flicker-free display of office applications such as word processing and spreadsheet programs offered; MDA was thus one of the crucial factors that contributed to the success of IBM - compatible PCs.

The alternate graphic-capable IBM standard from the year of introduction of the IBM XT computer was CGA, which could represent both color graphics as well as text, but a lower resolution and refresh rate exhibited.

MDA plug-in cards for XT- compatible PCs are the precursors of today's graphics cards; among the successor standard EGA (1984 ), MCGA and later VGA and SVGA (1989, specified by VESA).