134 results about "Read-modify-write" patented technology

A method, system, apparatus, and computer-readable medium are provided for taking snapshots of a storage volume. According to aspects of one method, each snapshot is represented as a unique sequence number. Every fresh write access to a volume in a new snapshot lifetime is allocated a new section in the disk, called a provision, which is labeled with the sequence number. Read-modify-write operations are performed on a sub-provision level at the granularity of a chunk. Because each provision contains chunks with valid data and chunks with invalid data, a bitmap is utilized to identify the valid and invalid chunks with each provision. Provisions corresponding to different snapshots are arranged in a linked list. Branches from the linked list can be created for storing writable snapshots. Provisions may also be deleted and rolled back by manipulating the contents of the linked lists.

A high-speed memory system is disclosed for use in supporting a directory-based cache coherency protocol. The memory system includes at least one data system for storing data, and a corresponding directory system for storing the corresponding cache coherency information. Each data storage operation involves a block transfer operation performed to multiple sequential addresses within the data system. Each data storage operation occurs in conjunction with an associated read-modify-write operation performed on cache coherency information stored within the corresponding directory system. Multiple ones of the data storage operations may be occurring within one or more of the data systems in parallel. Likewise, multiple ones of the read-modify-write operations may be performed to one or more of the directory systems in parallel. The transfer of address, control, and data signals for these concurrently performed operations occurs in an interleaved manner. The use of block transfer operations in combination with the interleaved transfer of signals to memory systems prevents the overhead associated with the read-modify-write operations from substantially impacting system performance. This is true even when data and directory systems are implemented using the same memory technology.

A programmable logic device, such as a field programmable gate array, is partially reconfigured using a read-modify-write scheme that is controlled by a processor. The partial reconfiguration includes (1) loading a base set of configuration data values into a configuration memory array of the programmable logic device, thereby configuring the programmable logic device; (2) reading a first frame of configuration data values from the configuration memory array; (3) modifying a subset of the configuration data values in the first frame of configuration data values, thereby creating a first modified frame of configuration data values; and (4) overwriting the first frame of configuration data values in the configuration memory array with the first modified frame of configuration data values, thereby partially reconfiguring the programmable logic device. The steps of reading, modifying and overwriting are performed under the control of a processor.

A digital computer performs read-modify-write (RMW) processing on each bit of a row of memory in parallel, in one operation cycle, comprising: (a) addressing a memory, (b) reading each bit of a row of data from the memory in parallel, (c) performing the same computational operation on each bit of the data in parallel, using an arithmetic logic unit (ALU) in a dedicated processing element, and (d) writing the result of the operation back into the original memory location for each bit in the row.

A method for resource notification is disclosed. The method generally comprises the steps of (A) buffering a plurality of messages received from a plurality of busses, (B) arbitrating among the messages, (C) writing the messages in response to the arbitration, and (D) generating a plurality of notification signals on a plurality of lines in response to the messages as written to a plurality of addresses.

The invention discloses an RAID (redundant array of independent disc) 5-orientated optical design method for a writing operation in continuous data storage. The method comprises the steps of: in continuous data storage application, saving writing data blocks, transmitted by an application program, in a memory buffer area; constructing an alignment data block of which the length is the same as that of a complete strip of an RAID5; then enabling the alignment data block to fill the overall strip opportunely on the RAID5; and then transmitting the alignment data block to the RAID5 so as to write the overall strip of the RAID5. Therefore, the written data blocks fill the overall strip of the RAID5 opportunely to avoid the expense for generating the verification of reconstruction, read-modify-write and the like; and the continuity of the data blocks avoids the expense of track seeking of a magnetic head, and improves the throughput capacity of a storage system. Simultaneously, the data blocks written into the RAID5 are sequenced and are written into adjacent strips continuously so as to realize the continuous I/O transmission of the RAID5. The invention is also suitable for an RAID6.

A system and method for reducing the number of memory accesses by a hardware device to a descriptor memory is disclosed. Methods, systems and articles of manufacture consistent with the present invention enable software to embed a subsequent descriptor it is posting in the descriptor memory into a current descriptor listed in the descriptor memory. Additionally, hardware is configured to transmit a data packet associated with the current descriptor to a recipient device. When hardware receives an acknowledgment message from the recipient device associated with the transmitted data packet, it fetches the current descriptor to update a completion code within the current descriptor using a Read-Modify-Write (RMW) transfer sequence. As part of the RMW memory operation, hardware may use the embedded copy of the subsequent descriptor within the current descriptor to transmit the next data packet associated with the subsequent descriptor. This process avoids hardware from having to fetch the embedded descriptor from the descriptor memory before transmitting the next data packet.

A system and method for locking and unlocking access to a shared memory for atomic operations provides immediate feedback indicating whether or not the lock was successful. Read data is returned to the requestor with the lock status. The lock status may be changed concurrently when locking during a read or unlocking during a write. Therefore, it is not necessary to check the lock status as a separate transaction prior to or during a read-modify-write operation. Additionally, a lock or unlock may be explicitly specified for each atomic memory operation. Therefore, lock operations are not performed for operations that do not modify the contents of a memory location.

A method, system, apparatus, and computer-readable medium are provided for synchronizing I/O operations in a computer system. According to aspects of the invention, multiple reader and writer locks are provided that may be acquired by calling processes at two different granularities. Locks may be acquired for an area of storage equivalent to the logical unit of allocation or for a sub-provision area equivalent to a unit of snapshot read-modify-write. Each lock is represented by a lock data structure that represents the same amount of logical address space as the logical unit of allocation. A request that arrives to the lock data structure is made to wait in a lock wait queue until the request can be honored. Requests that have been honored but that have not yet released the lock are maintained in a dispatch queue. When a writer lock is assigned to a lock request, no other readers or writers may be allocated to it. When a reader lock is assigned to a lock request, the lock may also be given to other readers, but not to a writer. A round robin technique is utilized to respond to requests for locks so that one lock does not starve the other locks.

A pipeline configuration is described for use in network traffic management for the hardware scheduling of events arranged in a hierarchical linkage. The configuration reduces costs by minimizing the use of external SRAM memory devices. This results in some external memory devices being shared by different types of control blocks, such as flow queue control blocks, frame control blocks and hierarchy control blocks. Both SRAM and DRAM memory devices are used, depending on the content of the control block (Read-Modify-Write or ‘read’ only) at enqueue and dequeue, or Read-Modify-Write solely at dequeue. The scheduler utilizes time-based calendars and weighted fair queueing calendars in the egress calendar design. Control blocks that are accessed infrequently are stored in DRAM memory while those accessed frequently are stored in SRAM.

A system comprises a plurality of memory controllers connected to a memory bus. Each memory controller is able to generate memory requests on the memory bus according to a predetermined priority scheme. One priority scheme is a time slot priority scheme, and another priority scheme is a request-select priority scheme. The plurality of memory controllers are able to monitor memory requests generated by another memory controller in performing memory-related actions, such as memory requests (read or write), read-modify-write transaction, and cache coherency actions. In one arrangement, the memory bus is a Rambus channel.

Systems and methods for controlling memory access operations are disclosed. The system may include one or more requestors performing requests to memory devices. Within a memory controller, a request queue receives requests from a requestor, a bank decoder determines a destination bank, and the request is placed in an appropriate bank queue. An ordering unit determines if the current request can be reordered relative to the received order and generates a new memory cycle order based on the reordering determination. The reordering may be based on whether there are multiple requests to the same memory page, multiple reads, or multiple writes. A memory interface executes each memory request in the memory cycle order. A data buffer holds write data until it is written to the memory and read data until it is returned to the requestor. The data buffer also may hold memory words used in read-modify-write operations.

In-memory accumulation of hardware counts in a computer system is carried out by continuously sending count values from full-speed hardware counter units to a memory controller. A sending unit periodically samples performance data from the hardware counter units, and transmits count values to a bus interface for an interconnection bus which communicates with the memory controller. The memory controller responsively updates an accumulated count value stored in system memory using the current count value, e.g., incrementing the accumulated count value. A count value can be sent with a pointer to a memory location and an instruction on how the location is to be updated. The instruction may be an atomic read-modify-write operation, and the memory controller can include a dedicated arithmetic logic unit to carry out that operation. A data harvester can then be used to harvest accumulated count values by reading them from a table in system memory.

Systems and methods for providing data modification operations in memory subsystems. Systems include a plurality of memory devices, a memory controller, one or more memory busses connected to the memory controller and a memory hub device. The memory controller receives and responds to memory access requests including memory update requests from a processor. The memory controller also generates a memory update command in response to receiving a memory update request. The memory hub device includes a first port, a second port and a control unit. The first port is in communication with the memory controller via one or more of the memory busses for transferring data and control information between the memory hub device and the memory controller. The second port is in communication with one or more of the memory devices. The control unit decodes the memory update command from the data and control information and accesses the memory devices via the second port to perform the memory update command local to the memory hub devices as a logical read-modify-write sequence.

Provided are a memory controller with data read-modify-write function, and a system-on-chip (SOC) having such a memory controller, where the memory controller is connected to a memory, the memory controller is connected to IP (intellectual property) blocks and a microprocessor via a system bus, and, in response to one of read, write, and modify request signals received from the one of the IP blocks or the microprocessor and an address signal, the memory controller reads a data signal from the memory, writes a write data signal to the memory, or modifies the data signal read from the memory and writes the modified data signal to the memory such that the memory controller and the SOC can reduce occupation time for the system bus and access time for the memory and additionally reduce unnecessary power consumption.

A data processing system includes a command buffer and control circuitry. The command buffer is configured to store pending write requests to a memory in which each pending write request has corresponding write data. The control circuitry is configured to select a pending write request from an entry of the command buffer and send the selected write request to the memory. The selected write request is a partial write request having first write data stored in the entry. Sending the selected write request includes performing a read-modify-write (RMW), wherein the control circuitry is configured to, after a read operation of the RMW, update the pending write request in the entry from a partial write request to a full write request.