Abstract: A mapping-type data signal optimizer performs a multi-pass scan to optimize multiple-plane symbol buffers. A total of seven scanning passes of the difference map planes is made: A triple-plane scan in search of white characters; three dual-plan scans in search of turquoise, yellow, and pink characters, respectively; and three single-pass scans in search of red, blue, and green characters, respectively. This minimizes the length of the output signal required to effect the changes to the multiple planes. The optimizer performs an MDT-reset voting routine to determine whether selective setting of modified data tags (MDTs) can be done more effectively by (a) clearing all MDTs and individually setting desired MDTs, or (b) clearing desired MDTs. The approach resulting in the shorter signal is utilized.

Abstract: An optimizer system optomizes and validates data streams in whcih double-byte character set data may be transmitted. The optimizer, maintaining an image or map of data contained in a peripheral device buffer, sets and monitors the status of three flags located in extended attribute planes for the purpose of processing data stream orders when a double-byte character set is in use.

Abstract: A mapping-type data signal optimizer performs a code-point sorting function to optimize downloading of programmed symbols. A present-state list of values of programmed symbols already downloaded to a peripheral device is sorted, and a similar intended-state list of programmed symbols intended to be downloaded is likewise sorted. A search is performed to detect any commonalities that might exist between the present-state and intended-state programmed-symbol values, even under differing programmed-symbol designators. When such a commonality is detected, the intended- state designator is altered to be equal to the present-state designator; thus, that particular programmed symbol value need not be redownloaded.

Abstract: ERASE INPUT support is provided for the optimizer system disclosed in commonly-assigned co-pending application Ser. No. 827,767, now U.S. Pat. No. 4,750,137, by altering the programming of the optimizer system so that the only MDT flags turned off in the optimized outgoing data stream are those associated with protected pre-modified fields. The programming is further altered so that when an incoming data stream is received by the optimizer system, all unprotected fields in the present-state image are preprocessed prior to being updated from the incoming data stream to reflect the information available to the optimizer system as to whether the ERASE INPUT key has been pressed.

Abstract: A method and a computer program for performing the method are disclosed for optimizing signals being exchanged between a host unit and an addressable-buffer peripheral device. The program optimizes an outgoing signal from the host unit by (1) creating an updated-state map representing the state of the peripheral device buffer expected to exist after processing by the peripheral device of the outgoing signal, (2) performing an exclusive-or (XOR) operation using the updated-state map and a present-state map representing the existing state of the buffer, and (3) constructing and transmitting a substitute outgoing signal which represents only changes to the buffer, and in which all premodified field flags are turned off. Position-dependent characters, such as attribute bytes, are translated into nondata characters prior to incorporation into a map, and are retranslated into their original form for use in the substitute signal.