Abstract: Methods and apparatus for a memory system using line termination circuits in each memory unit (e.g., integrated circuit memory device) are disclosed. The memory unit contains termination control logic that sets the state of a controllable termination circuit to control reflections on the data bus. The termination control logic determines the proper state for the termination circuit from the state of its memory unit, and in some cases, from the approximate state of the data bus as gleaned from commands decoded from the command/address bus. A termination configuration register on the unit can be used to define the appropriate termination state for each unit state and/or data bus state.

Abstract: System for transferring a data file from a web server to a user workstation through a network and reciprocally, the user workstation including a hard disk (205) for storing the data file being transferred over a SCSI bus (208). The user workstation includes a dual-port memory (304) for storing temporarily the data file, a network logic unit (302) interconnected between the network and the input port of the dual-port memory for receiving the data file from the network and transmitting it to the dual-port memory, and a SCSI logic unit (303) interconnected between the output port of the dual-port memory and the SCSI bus for transferring the data file from the dual-port memory to the hard disk over the SCSI bus and reciprocally.

Abstract: In order to propose a signal input and output apparatus for changing over control depending on a detection result by discriminating the type of signals when signals of two or more types are passed in the same signal line, a signal input and output apparatus comprises signal discrimination changeover means for discriminating the type of control signal through cable, plug and jack, as a transmission path generating a discrimination signal, supplying it to a controller, and changing over the control of a signal processor to the controller on the basis of the discrimination signal, and thereby input and output of plural control signals can be processed through a single transmission path. As a result, by a single jack only, plural signals can be passed on the same transmission path by optimizing the transmission and reception paths and transmission and reception elements, and therefore the parts mounting area can be saved, and states of various types of signals can be detected.

Abstract: An improved descriptor system is provided in which read pointers indicate to a host and a peripheral the next location to read from a queue of descriptors, and write pointers indicate the next location to be written in a queue. The system also allows an incoming descriptor to point to a plurality of data frames for transfer to the host processor, wherein the peripheral need not read a new descriptor each time a frame is to be transferred to the host.

Abstract: Command data may be embedded in the data transmitted over an interconnect between video devices to specify memory addresses in a destination device. Using an embedded address allows address-dependent data to be transmitted over the interconnect without losing these attributes. For example, compressed video may be transferred from a disk controller to a memory device using this interconnection protocol without losing address attributes of the bus architecture. The address information may be used either to read data from or to write data to a device over the interconnect into randomly-accessible memory locations.

Abstract: Methods and devices for monitoring distributed electric power are disclosed, including energy devices with a sensor for monitoring an electric circuit, and a memory to store sensor measurements. Various techniques are disclosed for using polymeric RAM, 1T-DRAM, enhanced SRAM, magnetoresistive RAM, organic RAM, chalcogenide RAM, holographic memory, PLEDM, single-electron RAM, fractal cluster glass memory and other technologies in energy devices with high-endurance, high-density, high-capacity, non-volatile, solid-state, or removable memories.

Abstract: The address of a data packet to be transferred from a memory to a network interface card within a direct memory access (DMA) is checked. First of all, the address of a descriptor corresponding to the data packet is read from the memory, wherein the descriptor contains information of the address of the data packet. Then, whether the address of the descriptor complies with a certain rule is determined. If the address of the descriptor does not comply with the certain rule, an interrupt signal is asserted to a processor to perform a corresponding interrupt service in order to re-read the address of the descriptor.

Abstract: A computer system component serves as a burst mode data transfer proxy for bridging a bus operable in burst transfer mode and a single transfer mode bus. FIFOs, associated with respective DMA channels, provide a shared area for assembling and disassembling bursts on behalf of subsystems on the single transfer mode bus. The component also performs DMA functions.

Abstract: A data transfer device (10) converts the data stream input to it by IEEE 1394 isochronous transmission from an image processing device (20) connected to it into data in a color signal mode adapted to PCI transfer by means of a converter circuit (219), while controlling an address of PCI bridge circuit (216B) as bus master, transmits the image data from the converter circuit (219) to a graphic memory (221) by DMA transmission by way of a PCI bus (215) and writes the data in the graphic memory (221) by means of a graphic control circuit (220). It then reads the image data from the graphic memory (221) by means of the graphic control circuit (220) and transfers the data to an electronic device (30).

Abstract: A system and method of enhanced backplane messaging among a plurality of computer boards communicating over a common bus uses a set of pre-allocated buffers on each computer board to receive messages from other computer boards. Each sending computer board is represented on each remote computer board by a descriptor ring with pointers to pre-allocated buffers on that remote computer board. When a sending computer board has a message to deliver to a remote computer board, the sending computer board uses its DMA controller to transfer the message into the pre-allocated buffers on the remote computer board. The sending computer board also sends a mailbox interrupt to the remote computer board. The remote computer board interrupt handler moves the messages from the descriptor rings to the receiving application(s) via pointer manipulation. Chained DMA transfers are used to eliminate any data transfers by the processor itself across the bus.

Abstract: A packet memory system is provided. The packet memory system includes a memory cell array for storing a predefined number of packets. Each packet includes a predetermined number of segments. Each of the segments defines a starting point of a memory access. A packet decoder coupled to the memory cell array receives packet select inputs for selecting a packet. A segment decoder coupled to the memory cell array receives segment select inputs for selecting a segment. A data flow multiplexer is coupled to the memory cell array for transferring data between a data bus and the memory cell array. Command and mode registers receive command, read/write (R/W) and chip select (CS) inputs for opening a packet. Responsive to an opened packet, the packet select inputs provide a length for the memory access. Each of the segments has a preprogrammed length. Also each of the segments can be defined for a cache line.

Abstract: A system including at least two processing units embedded on a chip able to communicate with each other and to generally independently control access to data from memory on the chip.

Abstract: A method and apparatus of memory access control for bus masters are described. In one embodiment, the method includes the receipt of a direct memory access (DMA) request from a device. Once the DMA request is received, DMA access rights of the device are determined according to an access control list (ACL). Once determined, the device is granted DMA access according to the determined memory access rights of the device. In other words, if a DMA request coincides with DMA access rights assigned to the device, the DMA request is executed. Otherwise, the operating system may be notified of an unauthorized DMA request.

Abstract: The present invention relates to a method and apparatus for a vehicle control system comprising electronic modules used for the automatic control of vehicle operation. The method for automatic storing of configuration file data of at least three electronic modules for the automatic control of vehicle operation, the electronic modules being coupled in a network. Automatically collecting a value of a parameter stored in the electronic modules, deciding which of the collected values should be maintained as being a correct value of the parameter, and sending and/or storing the correct value of the parameter to electronic modules which did not send this value for the parameter during the collection step. A corresponding device is also provided.

Abstract: A DSP device is disclosed having multiple DMA controllers with global DMA access to all volatile memory resources in the DSP device. In a preferred embodiment, each of the DMA controllers is coupled to each of the memory buses and is configured to control each of the memory buses. A memory bus multiplexer may be coupled between the subsystem memory bus and each of the DMA controllers, and an arbiter may be used to set the memory bus multiplexer so as to allow any one of the DMA controllers to control the memory bus. The memory bus may also be controlled by the host port interface via the memory bus multiplexer. A round-robin arbitration technique is used to provide each of the controllers and the host port interface fair access to the memory bus. This approach may advantageously provide increased flexibility in the use of DMA controllers to transfer data from place to place, with only a minimal increase in complexity.

Abstract: An electronic control device with a parallel databus and a plurality of assemblies connected to the databus. The assemblies each include a processor and a memory device and are connected to the databus with a bus controller. The data are transmitted between a transmitter assembly and a receiver assembly with messages. The data bus essentially corresponds to the MULTIBUS II. The bus controller of the transmitter assembly is fashioned such that, without making use of the processor of the transmitter assembly, it reads data stored in the memory device of the transmitter assembly in response to a request message of the receiver assembly and sends them to the receiver assembly.

Abstract: The present invention is a data transfer protocol control system with a host bus interface that includes a transmitting/receiving command DMA, a transmitting data DMA and a receiving data DMA for controlling data transfer protocol with a host bus interface considering characteristic, usage frequency, simultaneous processing functions of the command DMA and the data DMAs. A host interface bus is efficiently used and bus usage ratio is distributed properly to support transfer flow properly and improve the entire system performance.

Abstract: A system includes a direct memory access (DMA) engine to move data on a real time basis and a communication front-end to transmit and receive the data. In another embodiment, the system may also include a medium access control (MAC) to control transmission and reception of the data and that may be partitioned or divided according to response times to carry out selected functions.

Abstract: An apparatus and method for transferring multi-byte words having arbitrary start and end byte addresses are described. Data transfers between a memory and a PCI-bus pass through a PCI-side aligner unit, PCI FIFO, Endian swap logic, and PCI-bus interface unit under the control of a PCI FIFO controller. The PCI-side aligner unit properly aligns the data while communicating data with the memory's bus on a word-at-a-time basis, and communicating data with the PCI FIFO managed on a byte-at-a-time basis synchronous with a clock signal provided by the memory's bus. The Endian swap logic properly orients the data in big or little Endian orientation. The PCI-bus interface unit communicates data with the PCI-bus on a word-at-a-time basis, and communicates data with the PCI FIFO managed on a byte-at-a-time basis synchronous with a clock signal provided by the PCI-bus.

Abstract: Described are methods for accurately measuring the skew of clock distribution networks on programmable logic devices. Clock distribution networks are modeled using a sequence of oscillators formed on the device using configurable logic. Each oscillator includes a portion of the network, and consequently oscillates at a frequency that depends on the signal propagation delay associated with the included portion of the network. The various oscillator configurations are defined mathematically as the sum of a series of delays, with the period of each oscillator representing the sum. The respective equations of the oscillators are combined to solve for the delay contribution of the included portion of the clock network. The delay associated with the included portion of the clock network can be combined with similar measurements for other portions of the clock network to more completely describe the network.

Abstract: A DMA controller arbitrates and selects a DMA control information signal received from at least one of a plurality of DMA request blocks and accesses an SDRAM on the basis of the selected DMA control information signal. In the DMA controller, an SDRAM controller detects using a detector the number of possible sequential accesses on the basis of a DMA start address signal, compares using a comparator this number of possible sequential accesses with the burst DMA request number designated by a BSTNUM signal, selects not larger one of the two numbers, and sets the number of sequential DMAs to be actually executed to the selected number. Accordingly, with a simple configuration, sequential access is made possible starting from an arbitrary address.

Abstract: In a data processing system including a plurality of digital signal processor subsystems, selected peripheral components are shared by the digital signal processor subsystems. In particular, the high level data link controller is shared by the subsystems. When a packet is received by a shared high level data link controller, the data signal groups are processed and placed in a temporary storage unit. The address signal group of the received packet is applied to channel block unit where the digital signal processor subsystem, to which the packet is directed, is identified and an INTERRUPT signal corresponding to the identified digital signal processor subsystem is generated. The INTERRUPT signal is applied to a switch. The switch, which receives the signal groups from the temporary storage unit, directs the signal groups to a buffer memory in the channel associated with the identified signal processing subsystem.

Abstract: A data transfer control system receives a command packet ORB transferred through a bus BUS 1 (IEEE 1394), issues a command indicated by ORB to a device connected to a bus BUS2 (ATA (IDE)/ATAPI), and orders start of a DMA transfer. The command issued based on ORB is aborted after the completion of the DMA transfer. The data transfer control system compares contents of a command packet ORB1 transferred before a bus reset with contents of a command packet ORB2 transferred after the bus reset. If the contents are different, a command issued based on ORB1 is aborted after completion of a DMA transfer. Dummy data is transferred between the data transfer control system and the device connected to the bus BUS2 until a DMA transfer is completed. Dummy data transfer is controlled by performing a dummy update on a pointer.

Abstract: A microprocessor system includes a high speed primary bus, a plurality of master devices coupled to the high speed primary bus, and a plurality of peripherals coupled to the high speed primary bus. The peripherals include at least one memory. An arbiter circuit is coupled to the high speed primary bus for managing access requests to the high speed primary bus by any one of the master devices. The microprocessor system further includes a secondary bus, and a bridge interface circuit coupled between the high speed primary bus and the secondary bus. The bridge interface circuit includes a direct memory access controller so that during each data transfer routine between a peripheral connected to the secondary bus and one of the peripherals reduces to a single transfer phase engagement of the high speed primary bus.

Abstract: A digital signal processor includes a byte direct memory access (DMA) controller and an external memory controller, both of which are coupled to each other. The external memory controller is coupled to a byte memory and other external memories through a common data bus. The byte DMA controller performs a byte DMA operation to the byte memory through the common data bus by controlling the external memory, thereby avoiding an additional data bus. As a result, the digital signal processor according to the present invention has less connecting terminals and achieves a size reduction.

Abstract: A cable modem having a programmable media access controller (MAC). A single cable modem device includes all necessary MAC functions. The invention allows programmable MAC functions to support evolving standards (e.g., DOCSIS) without requiring expensive hardware upgrades. Bifurcated microprocessor architecture, in which first processing circuitry is programmed to implement MAC functionality for processing information flowing to and from cable media interface circuitry, and second embedded processor core or host system processor provides operating system functionality are used. Alternatively, separate processor cores provide MAC functionality for downstream and upstream data paths, respectively. Cable media interface circuitry, and other peripheral circuitry, are coupled to a peripheral bus that is linked by a bridge circuit to a system bus. The processing circuitry MAC is communicatively coupled to the system bus.

Abstract: A plurality of direct memory access data transfers are accomplished to transfer data from a host to an adaptor. For each transfer, an indication of locations of at least one group of storage locations associated with the host available to hold the data to be transferred to the host is provided from the host to the adaptor. An indication of the provided indication is maintained, for that transfer, by the host. Based on the indication of locations provided from the host to the adaptor, data is transferred to the at least one group of storage locations from the adaptor. An indication is provided from the adaptor to the host that the data transferring step has been completed with respect to the at least one group of storage locations. The host determines the locations corresponding to the at least one group of storage locations based on the indications maintained by the host and retrieving the data from the at least one group of storage locations based on the determination.

Abstract: A physical interface card for connection to a data bus associated with a data network node is provided. The physical interface card is adapted to perform without supervision from other data bus connected devices: byte ordering, byte alignment and byte scattering/gathering in conveying data between a data bus connected central memory block and at least one data channel associated with the physical interface card. The functionality is provided via a special function direct memory address device operating in accordance with byte ordering specifications for: data stored in the shared memory block and data conveyed via the at least one data channel. The byte alignment is enabled by direct byte addressing techniques as well as the use of an orphan counter to keep track of processed bytes. An implementation of the orphan counter as a state machine reduces processing overheads.

Abstract: In a recordable disk recording controller circuit, a data buffer manager receives a command and sends the command to a micro-controller. The micro-controller generates a set of register batches from each command and sends the register data and index of the register batch to a batch register controller. The batch register controller receives the register data and index of the register batch from the micro-controller and stores the received register data and index of the register batch in a batch buffer. The batch register controller retrieves the register batches from the batch buffer and writes the master registers of an encoder controller based on the register index and register data of the register batches after the master registers of the encoder controller are updated into the slave registers of the encoder controller. The encoder controller generates control signals to a recording circuit depending on updated slave registers.

Abstract: A system/method of enhanced backplane messaging among a plurality of computer boards communicating over a common bus uses a set of pre-allocated buffers on each computer board to receive messages from other computer boards. Each sending computer board is represented on each remote computer board by a descriptor ring with pointers to pre-allocated buffers on that remote computer board. When a sending computer board has a message to deliver to a remote computer board, the sending computer board uses its DMA controller to transfer the message into the pre-allocated buffers on the remote computer board. The sending computer board also sends a mailbox interrupt to the remote computer board. The remote computer board interrupt handler searches its descriptor rings and manipulates a series of pointers to move messages from the descriptor rings to the intended receiving application(s). Pointer manipulation is also used to replenish the descriptor ring(s) with empty buffer(s).

Abstract: Controller for coupling data between a data storage system and a host includes a first processor and a first RAM coupled to the first processor; a first auxiliary processor including a first memory controller and a first cache coupled to the first memory controller, the first memory controller including first interface for coupling with second auxiliary processor including second memory controller and associated second cache and second interface for coupling with first auxiliary processor, first memory controller including logic for treating the caches as single memory; a bus coupling first primary processor and first auxiliary processor; and interconnection channel separate from the bus coupling first interface of first memory controlled and second interface of second memory controller. Interconnection may be an out-of-band channel permitting device-to-device sharing of associated cache memories without requiring data transfer over the bus. Method and computer program product are also provided.

Abstract: The template data transfer coprocessor (TDTP) offloads block data transfer operations from a mediaprocessor. A uni-block template, program-guided template, an indirect template and queue-based template are described. The TDTP includes a template interpreter that employs an event-driven control mechanism to set up a template and compute block information and block information for each template. The programming involved in defining block data transfers for video and image processing algorithms is substantially reduced by the use of these templates.

Abstract: A processor system includes an I/O bus to host bridge in which I/O address translation elements are shared across multiple I/O bus bridges. A TCE manager is provided for retaining in cache a TCE entry associated with a discarded channel for association with a new channel responsive to a subsequent read request for a memory page referenced by the TCE entry.

Abstract: A memory access processor and memory access interface for transferring data information to and from a plurality of SSRAM locations. The processor has a lookup controller for identifying a data request and locating the data requested from the SSRAM locations. The bus allows a data request and retrieval throughput from a routing processor to the memory access processor at a maximum rate, about 10 gigabits per second without substantial pipeline stalls or overflows.

Abstract: A method for avoiding data collision in a half-duplex mode using a DMA logic for multi-point linked processors is disclosed. According to the disclosed method, a transmitting processor holds a request-to-send (RTS) signal in an active state for a prescribed period of time so that a transmitting DMA logic of a receiving processor can be initiated after the operation of a receiving DMA logic of the receiving processor is terminated. Since the Tx DMA logic of the receiving processor starts data transmission after the Rx DMA logic of the receiving processor completes receiving of data, data collisions occurring in the receiving processor due to the concurrent operation of the Tx DMA logic and the Rx DMA logic can be prevented.

Abstract: A transfer destination address generator includes an arithmetic device that calculates a difference between a transfer destination address and a transfer source address, a difference holding register that stores the difference, and an arithmetic device that calculates the transfer destination address based on the difference stored in the difference holding register, and on the transfer source address. A transfer source address generator includes a transfer source address register that stores a present value of the transfer source address, and a transfer source reload register that stores an initial value of the transfer source address.

Abstract: A data transfer system comprising a first bus interface, a second bus interface, a first-in-first-out memory, a controller and a message unit. The message unit is operable to queue a plurality of data transfer request messages from the first bus interface and the second bus interface. The controller is operable to process each data transfer request message and transfer data between the first bus interface, the first-in-first-out memory and the second bus interface. The controller is configured to calculate error detection codes (EDCs) and chain EDC values.

Abstract: An apparatus includes one or more interface circuits, an interconnect, a memory controller, a memory bridge, a packet DMA circuit, and a switch. The memory controller, the memory bridge, and the packet DMA circuit are coupled to the interconnect. Each interface circuit is coupled to a respective interface to receive packets and/or coherency commands from the interface. The switch is coupled to the interface circuits, the memory bridge, and the packet DMA circuit. The switch is configured to route the coherency commands from the interface circuits to the memory bridge and the packets from the interface circuits to the packet DMA circuit. The memory bridge is configured to initiate corresponding transactions on the interconnect in response to at least some of the coherency commands. The packet DMA circuit is configured to transmit write transactions on the interconnect to the memory controller to store the packets in memory.

Abstract: A multiple bus architecture includes multiple processors, and one or more shared peripherals such as memory. The architecture includes plural bus masters, each connected to its own bus. There are also plural bus slaves, each connected to its own bus. A bus arbitration module selectively interconnects the buses, so that when the plural bus masters each access a different bus slave, no blocking occurs, and when the plural bus masers each access a same bus slave, bandwidth starvation is avoided. The architecture is supported by a bus arbitration method including hierarchical application of an interrupt-based method, an assigned slot rotation method and a round-robin method, which avoids both bandwidth starvation and lockout during extended periods of bus contention.

Abstract: A single completion status write back is generated by a controller to inform a driver of completion of a transmission of all frames of an array of frames, as opposed to generating individual write backs for each frame. The driver identifies one of the frames that is reported with the completion status, and applies the completion status to that frame and to all frames of the array sent prior to that frame. Reducing the number of these overhead completion status write backs improves bus and data transfer efficiency.

Abstract: A system that supports a high performance, scalable, and efficient I/O port protocol to connect to I/O devices is disclosed. A distributed multiprocessing computer system contains a number of processors each coupled to an I/O bridge ASIC implementing the I/O port protocol. One or more I/O devices are coupled to the I/O bridge ASIC, each I/O device capable of accessing machine resources in the computer system by transmitting and receiving message packets. Machine resources in the computer system include data blocks, registers and interrupt queues. Each processor in the computer system is coupled to a memory module capable of storing data blocks shared between the processors. Coherence of the shared data blocks in this shared memory system is maintained using a directory based coherence protocol. Coherence of data blocks transferred during I/O device read and write accesses is maintained using the same coherence protocol as for the memory system.

Abstract: A controller generally comprising a DMA engine, a processor, and a circuit. The DMA engine may be configured to copy from a system memory to a local memory. The processor may be configured to process a message written in the local memory. The circuit may operate independently of the processor. The circuit may be configured to (i) monitor writes to the local memory for the message having a first pointer and (ii) program the DMA engine to copy a first buffer identified by the first pointer in response to the first pointer having a non-null value.

Abstract: A signal processing device includes an integrated processor, a video processing unit coding a video signal, and an interface controlling a bus ownership between the integrated processor and an external processor. The interface detects the integrated processor accessing an external device and asserts a bus request. Thus the signal processing device can process data with a shorter cycle and thus more efficiently.

Abstract: A computer system having a simple handshake protocol for implementing DMA transfers. A system bus is provided having a plurality of ports for coupling to system components including memory, central processing unit(s) and peripherals. A direct memory access controller (DMAC) is provided with a peripheral-independent interface coupled to the system bus and communicates with the system bus using system bus defined transactions. The DMAC comprises a set of registers. A central processing unit (CPU) configures teh DMAC by loading values into the DMAC registers. The configured DMAC issues an enable signal to a selected system component identified in the DMAC registers. A peripheral request interface is associated with the selected system components and communicates with the system bus using the system bus defined transactions. The selected system component asserts a request signal to the DMAC.

Abstract: A method and apparatus for accommodating the speed requirements of a DMA read request from PCI protocol I/O devices attached via a DMA to a multiprocessor system mesh. A bridge between the device controller and the mesh is described which buffers the data from the memory in cache lines from which the data is delivered finally to the I/O device. The system is adaptive in that the number of cache lines required in past reads are remembered and used to determine if the number of cache lines is reduced or increased.

Abstract: A direct memory access (DMA) circuit reduces the number of processor cycles involved in transmitting and receiving asynchronous transfer mode (ATM) cells. The circuit includes a read sequencer, a write sequencer, an ATM control block, a processor interface block, and a DMA arbitration and control block. The DMA arbitration and control block arbitrates between data transmissions on various subchannels. The ATM control block provides ATM functionality to the DMA circuit. The circuit may also respond to a trigger signal and may generate an interrupt signal. In this manner, the processing involved for DMA of ATM cells is improved.

Abstract: The read position or write position of data is decided by the base address of a ring buffer and an offset from the base address and the offset is updated by the amount of DMA-transferred data. When the offset becomes equal to or more than a value that indicates a total amount of transferred data, the offset is reset to zero to generate an address for circulating through and accessing the ring buffer. Moreover, a stop address showing the stop position of the DMA transfer operation is set to update the stop address by the amount of data read from or written in the ring buffer without depending on the DMA transfer operation. When the offset coincides with the stop address, the DMA transfer operation is stopped.

Abstract: A digital processing system comprises a central processing unit (CPU) operating in a virtual address domain for executing both operating system software and user software to perform various processing tasks; a direct memory access (DMA) controller; a memory management unit (MMU) programmed to translate virtual memory addresses to physical memory addresses; and a plurality of memory blocks for storing digital words in registers having physical addresses; wherein the DMA controller is governed by the CPU and is operable in the virtual address domain for controlling a transfer of digital words from a source block of memory to a destination block of memory through the MMU which translates the virtual source and destination memory addresses received from the DMA controller to corresponding source and destination physical addresses of the memory. Also disclosed is a method of operating the digital processing system.

Abstract: A switching system for controlling internal apparatuses provided within an exchange system includes a central controller and a switching module including a plurality of objective apparatuses, each objective apparatus including a control data end unit, controlled by the central controller based on DMA communication and SD/SCN signal. Further, the central controller includes a first processor access controller which transfers control data to the control data end unit, in order to check and control each of objective apparatus, based on the DMA communication and the SD/SCN signal. The switching module includes a second processor access controller which relays the control data transferred between the first processor access controller and a plurality of control data end units-based on the DMA communication and the SD/SCN signal.

Abstract: A method, system, and computer program product for enforcing logical partitioning of input/output slots within a data processing system is provided. In one embodiment, the system includes a hypervisor and at least one DMA address checking component. The hypervisor receives non-direct-memory-access requests for access to input/output slots and prohibits devices within one logical partition from accessing the input/output slots assigned to a different logical partition. The DMA address checking component receives direct-memory-access requests and prohibits requests for addresses not within the same logical partition as the requesting device from being completed. Requests with addresses corresponding to the same logical partition as the requesting device are placed on the primary PCI bus by the DMA address checking component for delivery to the system memory.