Abstract: Processors communicatively attaching a storage sub-system and which place a message on a queue no longer have to wait on a queue lock set by another processor or sub-system dequeuing a message. This is realized by use of a double ended linked list or queue of messages having an isolation/reference point wherein an enqueuing end of the list is lockable and accessible independently from the dequeuing end of the list. The locking primitive may be of the multi-processor lock synchronizing atomic type such as TEST AND SET.

Abstract: A page modification method in a printer subsystem of the partial page buffer composing type. A printer subsystem receives a packet containing a page of characters, coded overlays/elisions, and combining data from an external source. The packet is translated into a linked list of character placement representations for each of the doubly indexed coded characters within the page. Elisions from the page are made by inhibiting the formation of a linked list segment for each character sequence within elision markers set out in the page. In contrast, coded character overlays are appended to the list as addenda. The list governs the placement of characters into a partial page buffer, whose contents are system accessible in row major order.

Abstract: A raster printer with sufficient flexibility so that text data and image data of any size and orientation can be placed at any position on a page. Input data has a succession of coded character data along with control data which specifies information concerning font selection and the placement of the characters on the page. Control circuits process the input data, one character at a time, and generate for each of the characters, data relating to the position of the character on the page, the size of the character and the address in storage of the graphic pattern for the character. The data is utilized by pattern move control logic to access the graphic pattern in the order the characters are to be printed and move the graphic data to a strip buffer. Data is read out of the strip buffer to energize imaging apparatus to print a page corresponding to the graphic pattern of the character data.