International Business Machines Corporation

Patrick J Hurley

Johnny G Barnes

Grover Herbert Neuman

James L Gaudet

Ernest L Miller

Rudolph E Chukran

Raymond A Thornton

Theodore M Cory

Harry L Lineman

Wade H Allen

John A Hooten

Gary W Miller

An impact printing system which is particularly suitable for word processing is provided with the capability of effecting mid-line pitch changes. The impact printer system which is particularly compatible with interactive display terminals in word processing system has means for receiving a selected one of a plurality of type or character font elements. The pitch of character font elements are different from each other. The printing system includes means for selectively impacting selected characters from selected fonts along lines in a document. The system further includes control apparatus for controlling and determining the selection of font elements to be used and in the case of printing with a particular font element, the characters to be printed in respective positions along the lines of the document to provide the desired document format. The control apparatus includes apparatus for controlling the printing with at least two different font elements having different pitch along a single line.

Impact printer with type font elements having mid-line pitch change

A system in which a device or machine is controlled by instructions from a data processor is provided which minimizes main memory storage requirements. An interrupt service routine monitors the input to the processor received from the device in response to control instructions sent by the processor. The interrupt service routine monitors this response for exception conditions. When an exception condition indicating that the device is no longer capable of fully carrying out processor instructions is received by the interrupt service routine, it activates an exception handler routine. A primary memory storage stack normally supports the interrupt service routine. However, upon the activation of the exception handler routine, this primary storage stack is switched to support the exception handler routine, and a secondary stack of significantly lower storage capacity is placed in support of the interrupt service routine which should have lower purported storage requirements during the active period of the exception handler routine. This results in a substantial saving of main processor memory capacity which otherwise would have to be dedicated to the support of the two respective routines.

Switching of programming routine supporting storage stacks

The present disclosure relates to word processing systems wherein material to be printed is formatted on a display unit having a display, e.g., CRT display and a text formatting processor which formats the display material. The display unit further includes means for controlling a printer to print the formatted text. In the present invention a plurality of such display units share a printer. This is accomplished by having at least one of the display units comprise means for controlling the sharing of the printer by the plurality of display units and each of the other display units communicate with the printer through these printer sharing control means. At least part of this printer sharing control means is contained in the text formatting processor of the primary display unit through which the other display units communicate with the printer.

Printer sharing by plurality of display units in word processing system

Overstruck text is justified by distributing the white space residue at the end of the unjustified line among the interword spaces for justification. The amount of the residue distributed is used to determine a number of overstrike characters which will overstrike the text including these expanded interword spaces. This is accomplished by placing controls in the text stream during editing to delineate the text to be overstruck. Before printing, these controls in the edited data stream are detected to cause the print line to be first justified by expansion of interword spaces and then followed by overstriking with the appropriate number of overstrike characters determined during the justification process.

Justification of overstruck text

A system for first justifying a text line according to a system minimum escapement unit, and then rejustifying the line according to a minimum escapement unit for a printer which is to be utilized in printing the line. The first justification of the line is in a normal manner. That is, any residue is divided by the number of word spaces on the line to obtain a quotient and any remainder. The extent of word space expansion is then the value of the quotient plus the remainder until exhausted. Rejustification for the printer being utilized is accomplished by dividing each system justified word space size by the printer minimum escapement unit to obtain a new quotient and remainder. Each system justified word space is then converted to a value including the obtained quotient for each space, and the remainders for all spaces are accumulated for adding to the first word space.

Growing community of inventors

Austin, TX, United States of America

Patrick J Hurley