Search results
Results from the WOW.Com Content Network
The main difference between System V shared memory (shmem) and memory mapped I/O (mmap) is that System V shared memory is persistent: unless explicitly removed by a process, it is kept in memory and remains available until the system is shut down. mmap'd memory is not persistent between application executions (unless it is backed by a file).
A memory-mapped file is a segment of virtual memory [1] that has been assigned a direct byte-for-byte correlation with some portion of a file or file-like resource. This resource is typically a file that is physically present on disk, but can also be a device, shared memory object, or other resource that an operating system can reference through a file descriptor.
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.
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).
The 16 Divisions of construction, as defined by the Construction Specifications Institute (CSI)'s MasterFormat, is the most widely used standard for organizing specifications and other written information for commercial and institutional building projects in the U.S. and Canada.
The mapping software outputs a real-time visual representation of the route. The map then moves along the path of the driver. If the driver drifts from the designated route, the navigation system will use the current coordinates to recalculate a route to the destination location.
MapQuest's original services were mapping (referred to as "Interactive Atlas") and driving directions (called "TripQuest"). [ 5 ] Sensing the emerging demand for spatial applications on the Internet, and with crippling network latency in Lancaster, the executive team of Barry Glick and Perry Evans moved MapQuest to the up-and-coming LoDo area ...
The Mass Rapid Transit Master Plan in Bangkok Metropolitan Region, or M-Map, is the latest version in a series of Thai government plans for the development of an urban rail transit network serving the Greater Bangkok area. It was drafted under the care of the Office of Transport and Traffic Policy and Planning (OTP) of the Ministry of Transport.