Abstract: In a data processing system in which two-level error correction is performed on variable length data being transferred between the host processor and the data storage device, the logical length of the data being transferred is computed during a fixed time gap with computation continuing after termination of the fixed time gap and commencement of the data transfer. The computation required for the logical length of the data field to accommodate two-level ECC is accomplished by first comparing the actual field length with a value predetermined by the subblock length of the two-level ECC. If the actual length is greater than the predetermined value, then a value equal to the subblock length plus first level ECC bytes is loaded into a counter which begins decrementing at the termination of the fixed time gap so as to synhronize by the byte-by-byte transfer of the data. As the data is being transferred the computation continues.

Abstract: Disclosed is a method for recording a record that emulates a first recording format, which includes a track reference point, such as an index field, used for determining a position of a record on a track according to the first recording format, on a moving storage device operating according to a second recording format which also includes a track reference point. The invention comprises the steps, responsive to location information generated according to the first recording formats, of:(1) determining an original angular position of a record according to the first recording format;(2) calculating in response to the original angular position and a parameter a preferred angular position for the record according to the second recording format;(3) determining an actual angular position of the record recorded according to the second recording format; and(4) recording an extension of the record to compensate for the difference between the preferred angular position and the actual angular position.

Abstract: A working data store simultaneously serves as a FIFO buffer and operating memory. A portion of the FIFO buffer is reallocated for use as an operating memory as processing needs arise.

Abstract: In a method and apparatus for reconstructing Chinese characters such as in a printer system, each of the characters is divided into a pair of components at least one of which occurs in one or more other characters. The components which have a height equal to the height of a standard character cell are stored together with information as to the locations of the components across the width of the standard character cell for each character. The components may be stored in a compressed form, in which event the information as to their location forms a part of the compressed data. When a given character is to be reconstructed, the first component thereof is transferred to a buffer where it is temporarily stored at the proper location across the width of a standard character cell. Thereafter, the second component is transferred to a logic circuit together with the temporarily stored first component, and the two are logically OR'ed to form the complete character.