Abstract: An exemplary point-to-multipoint network including an upstream headend facility and a plurality of downstream network terminals ("NTs") employs a contention-based multi-slot MAC permit protocol for upstream request transmission, wherein each NT compiles a congestion rank for each upstream slot position based on feedback information supplied by the headend. At such time as an NT wishes to attempt an upstream response to an multi-slot permit, it excludes the slot position having the highest rank for purposes of selecting an upstream response slot, and chooses among the others at random. If there are two or more slots having an equally high rank, the NT still excludes only one of the slots, based on a predetermined order of priority calculated at random from the NT's unique physical ID. If an NT is not successful with its initial response in the selected slot position, it will randomly select a waiting period of zero, one or two multi-slot permit cycles before attempting another upstream transmission.

Abstract: A communication controller transfers data cells and a control data cell representative of a target transmission rate from a system memory to a host; however, when a bus between the system memory and the communication controller is congested, the actual transmission rate for the data cells becomes smaller than the target transmission rate; a time stamp generator produces a time stamp representative of time for requesting a data transfer from the system memory, and a time stamp monitor compares the time stamp with actual stating time of transmission of the data cell to the host so as to check whether the target transmission rate is appropriate or not; if the target transmission rate is too large, the time stamp monitor requests a data processor to change the target transmission rate so that the data cells are transferred to the host at an appropriate transmission rate at all times.

Abstract: A video image data field to be compression-encoded is divided into rectangular blocks. Each of the rectangular blocks is compared with a corresponding block of a reference image to generate comparison data. The block of the image to be encoded is selected for representation if the comparison data for the block meets a selection criterion. The comparison data is generated on the basis of coefficients formed by applying an orthogonal transform to the blocks of the reference image and to the blocks of the image to be encoded. Mapping data is generated which is indicative of locations in the image plane corresponding to the selected blocks. The image to be encoded is represented in compressed form by header data, the mapping data and image data representative of the selected blocks. When the reference image is compression encoded, the blocks may be expanded in areas of the reference image which correspond to a low information density.

Abstract: A data transfer system has a PC as a host computer, a terminal unit such as a printer and a parallel interface cable through which data is transferred between the PC and the terminal unit. The PC transfers a strobe signal as a rate detection signal which contains points of change to the terminal unit. The terminal unit receives the strobe signal and calculates the data processing rate of the PC on the basis of the points of change of the strobe signal. The PC adjusts the data transfer rate of the PC on the basis of a result of comparison of the data processing rate of the PC calculated by the terminal unit and a processing rate of the terminal unit.

Abstract: A hard disk in a video data storage apparatus includes a first section in which video data is stored and appointed for permanent recording, and a second section in which the video data is stored subject to rewriting after a short period of time. If an alarm event occurs, some or all of the data in the second section may be secured for permanent storage. The process to be employed in securing the data in the second section for permanent storage is adapted to the proportion of the data in the second section which is desired to be secured.

Abstract: A symmetric multiprocessor system constructed from industry standard commodity components together with an advanced dual-ported memory controller. The multiprocessor system comprises a processor bus; up to four Intel Pentium.RTM. Pro processors connected to the processor bus; an I/O bus; a system memory; and a dual-ported memory controller connected to the system memory, the dual ported memory controller having a first port connected to the processor bus to manage processor to system memory transactions and a second port connected to the I/O bus to manage I/O transactions. Furthermore, two such systems can be connected together through a common I/O bus, thereby creating an eight-processor Pentium.RTM. Pro processor SMP system.

Abstract: A system and method for accessing parameters or objects using a tag parameter interface in a fieldbus system. The present invention enables access to parameters or objects using the tag parameter construct without requiring the user to perform any pre-configuration of connections or name to index mappings. This considerably simplifies user development of applications in a fieldbus network, wherein the user is completely shielded from all Fieldbus Foundation protocol details. According to the present invention, the user is not required to have any knowledge about the details of the VCR, how to set up or establish the VCR, or even that an entity called "VCR" exists in the system. Also, the present invention automatically maps the parameter name to an index, and thus the user is shielded from the details of construction of the device.

Abstract: A method for dynamically allocating the capacity of a computer network. All users of the network are classified as low or high priority users. High priority users may broadcast a delay message to the low priority users that cause the low priority users to delay before attempting to use the network. The length of delay can be adjusted if the high priority users are not able to utilize the network as required. In addition, if a low priority user does not receive a broadcast delay message within a predetermined amount of time, the delay period is reset to avoid unnecessary slowing of the network.