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The C programming language manages memory statically, automatically, or dynamically.Static-duration variables are allocated in main memory, usually along with the executable code of the program, and persist for the lifetime of the program; automatic-duration variables are allocated on the stack and come and go as functions are called and return.
The Word DMA (WDMA) interface is a method for transferring data between a computer (through an Advanced Technology Attachment (ATA) controller) and an ATA device; it was the fastest method until Ultra Direct Memory Access (UDMA) was implemented.
The DMA command is issued by specifying a pair of a local address and a remote address: for example when a SPE program issues a put DMA command, it specifies an address of its own local memory as the source and a virtual memory address (pointing to either the main memory or the local memory of another SPE) as the target, together with a block size.
C++ allows namespace-level constants, variables, and functions. In Java, such entities must belong to some given type, and therefore must be defined inside a type definition, either a class or an interface. In C++, objects are values, while in Java they are not. C++ uses value semantics by default, while Java always uses reference semantics. To ...
Gather/scatter is a type of memory addressing that at once collects (gathers) from, or stores (scatters) data to, multiple, arbitrary indices. Examples of its use include sparse linear algebra operations, [1] sorting algorithms, fast Fourier transforms, [2] and some computational graph theory problems. [3]
Intel 8237A-5, used on the original IBM PC motherboard Pinout. Intel 8237 is a direct memory access (DMA) controller, a part of the MCS 85 microprocessor family. It enables data transfer between memory and the I/O with reduced load on the system's main processor by providing the memory with control signals and memory address information during the DMA transfer.
Zero-copy programming techniques can be used when exchanging data within a user space process (i.e. between two or more threads, etc.) and/or between two or more processes (see also producer–consumer problem) and/or when data has to be accessed / copied / moved inside kernel space or between a user space process and kernel space portions of operating systems (OS).
Memory-mapped I/O is preferred in IA-32 and x86-64 based architectures because the instructions that perform port-based I/O are limited to one register: EAX, AX, and AL are the only registers that data can be moved into or out of, and either a byte-sized immediate value in the instruction or a value in register DX determines which port is the source or destination port of the transfer.