Abstract: A dual mode raster scanned character display system has a text mode of operation in which characters having a first matrix size are displayed on a CRT screen and a high resolution mode of operation in which display information is bit mapped on the CRT screen. Programmable font characters are stored in a memory and are accessed by controller characters generated in response to display requests supplied by an associated information source, such as a computer or a keyboard. Each controller character includes a special screen attribute multi-bit portion which is used to modify the font characters when coupled to a video signal generator unit to display reverse video, provide underline or strike through, specify one of two fixed intensities, suppress the character or provide a software function, such as CURSOR. In text mode, each character block has a fixed size appropriate to alphanumeric character generation, i.e.

Abstract: Data is stored on a rotating memory disk by maintaining constant the relative velocity between the recording transducer and the recording media. The rotational speed of the disk is varied as the transducer is translated radially of the disk recording surface, the disk surface being divided into a number of concentric track zones each containing a predetermined number of tracks. For any given zone, an optimum rotational motor speed is established and the rotational speed of the disk is maintained at that zone speed when the transducer position signals specify a given zone. As the transducer is commanded to step to a different track in a different zone, the rotational speed of the disk is altered to match the new zone speed within a relatively short period of time. Once the transducer is located within the given zone, the rotational disk speed is maintained at that zone speed for motion within the zone.