Search results
Results from the WOW.Com Content Network
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.
File-backed mapping maps an area of the process's virtual memory to files; that is, reading those areas of memory causes the file to be read. It is the default mapping type. Anonymous mapping maps an area of the process's virtual memory not backed by any file, made available via the MAP_ANONYMOUS/MAP_ANON flags.
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.
In computing, memory mapping may refer to: Memory-mapped file , also known as mmap() Memory-mapped I/O , an alternative to port I/O; a communication between CPU and peripheral device using the same instructions, and same bus, as between CPU and memory
File descriptors for a single process, file table and inode table. Note that multiple file descriptors can refer to the same file table entry (e.g., as a result of the dup system call [3]: 104 ) and that multiple file table entries can in turn refer to the same inode (if it has been opened multiple times; the table is still simplified because it represents inodes by file names, even though an ...
Free and open-source software portal; Lightning Memory-Mapped Database (LMDB) is an embedded transactional database in the form of a key-value store.LMDB is written in C with API bindings for several programming languages.
brk and anonymous mmaped-regions. This includes the heap and stack of user-space programs. It is written to swap when paged out. Non-anonymous (file-backed) mmaped regions. If present in memory and not privately modified the physical page is shared with file cache or buffer. Shared memory acquired through shm_open.
In computer science, a memory map is a structure of data (which usually resides in memory itself) that indicates how memory is laid out. The term "memory map" has different meanings in different contexts. It is the fastest and most flexible cache organization that uses an associative memory. The associative memory stores both the address and ...