Abstract: Program execution can be monitored and recorded for later playback. Certain state changes that can be predicted via a virtual processor during playback need not be recorded, so a compressed recording can be stored. To facilitate random access with respect to time during playback, key frames can be stored within the compressed recording. An index mechanism can associate key frames with particular memory addresses. Additionally, a snapshot of values for memory addresses can be used to further facilitate determining the value of a memory address without having to simulate execution. Multiprocessor executions can be supported, and playback can be done on a machine type different from that on which recording took place.

Abstract: Methods of recognizing rules, solid lines or rectangles, in a bit-mapped image and of using those rules to enable a suitable printer or other suitable device to receive the bit-mapped image quickly. In a preferred embodiment, the methods include the steps of recognizing rules, forming rule descriptors for the rules, and then transmitting the rule descriptors to the receiving device. Vertical rules are recognized by partitioning the bit-mapped image into a plurality of adjacent horizontal stripes of row data, dividing that horizontal stripe into data columns formed from vertically aligned row data bits, and ANDing the data bits in each vertically aligned column to identify, by a HIGH output from the AND function, vertical lines which span the horizontal stripe. Adjacent or continuous vertical lines are then identified. Horizontal rules are identified by dividing the row data into bytes, ANDing individual bits of each byte together, and recognizing a horizontal line by a HIGH output from the AND function.

Abstract: A method of transferring the digital representation of a bit-mapped image which includes the steps of: (1) identifying predefined patterns in the bit-mapped image data, and (2) transmitting pattern codes corresponding to those patterns to a receiving device. The identification of the patterns involves the partitioning of the bit-mapped image into a series of pattern cells and the scanning of those pattern cells to find preselected patterns. The preferred method of searching the pattern cells is based upon the use of a hashing function and hash tables. In response to the received pattern codes, the receiving device reconstructs the bit-mapped image associated with the pattern codes. After all patterns in the bit-mapped images are identified and sent to the receiving device, the non-recognized portions of the bit-mapped image are then sent. The overall bit-mapped image is recreated by combining the recognized patterns with the non-recognized portions in their original order.

Abstract: A system and method of transferring digital information corresponding to a bit-mapped image from a first device, such as a computer, to a suitable receiving device, such as a printer with adjustable margins. Raster columns within the bit-mapped image are recognized, the margins of the raster columns are defined, the margins of the receiving device are adjusted so that a single raster column is defined within the margins, and data comprising the raster column is sent to the receiving device in a manner that utilizes the automatic cursor reset capability of the receiving device. The raster columns are identified by scanning the bit-mapped image to identify columns of data separated by column-wise areas without HIGH data values.