Abstract: The invention relates to a procedure for scrolling some raster scan lines in a window of a screen operated in the graphic-mode of a personal computer. The computer has a processor and a program memory allocated to it as well as a video card connected to the processor via an external bus. The video card has a video memory (RAM), whose memory contents can be presented on the screen. One first line of the raster scan lines to be scrolled, is moved into a raster scan line within the window and is marked with a source-pointer. The raster scan line within a window, in which this line is to be moved into, is marked with a destination pointer. Afterwards, a scroll is performed and repeated until all lines to be scrolled are in raster scan lines of the window. At the same time with the first line, the subsequent third line is also at least scrolled in raster scan lines of the screen window.

Abstract: The invention relates to a procedure for the presentation of text in a CGA-graphic mode on a screen of a personal computer, which on one hand, shows a processor and a memory allocated to it, in which binary patterns of the text to be presented are stored and on the other hand, a video-card connected with such processor via an external bus. The video-card possesses a video-memory whose memory contents can be presented on the screen. For text-output a bit-sequence is produced for each pixel containing a two-bit sequence, especially 00, determining the background-color. The stored bit pattern of the text signs is connected with this bit-sequence. If the bit 0 exists in the stored bit pattern for the respective pixel, no change is made. If the bit 1 exists in the stored bit for the respective pixel, a bit sequence containing two bit is produced, which determines the desired front color and is stored in the video-memory.