Abstract: In the printer pin control circuitry described herein, data bits which request the actuation of respective pins are entered, indirectly, into respective digital equivalent shift registers to provide, for each pin, a respective short term history of actuation requests. A high speed, special purpose digital processor sequentially examines the several shift registers to determine, at successive points in time, whether each pin winding should then be energized or not to produce an effective energizing and damping waveform under a variety of sequential actuation conditions.

Abstract: In the apparatus disclosed herein, data recorded on a floppy disk in double density MFM mode is read back using a digital, adaptive time base system which permits accurate recovery of data despite bit shifting due to a high bit density on the magnetic recording surface. The adaptive time base provides successive data windows of non-uniform duration following detection of a data bit and, further, alters the starting reference time based upon the relation of the just received data bit to its predecessor.

Abstract: The printing apparatus disclosed herein generates alphanumeric characters of high quality, using a multi-pin printing head capable of forming discrete dots or pels, by controlling the actuation of the printing head with a timing resolution which is an order of magnitude finer than the nominal dot diameter so that a line smoothness for slanted or curved lines is obtained which is greater than that obtainable by a uniform matrix. The printing head is repeatedly traversed or scanned across the paper to provide essentially parallel lines of scan separated vertically by a distance which is a submultiple of the vertical spacing of the pins so that overlapping dots may be provided in the vertical dimension. By these means the apparatus facilitates the formation of smooth lines of essentially arbitrary slope or curvature.