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Video memory was shared with the first 128 KiB of RAM. The exact size of the video memory could be reconfigured by software to meet the needs of the current program. An early hybrid system was the Commodore Amiga which could run as a shared memory system, but would load executable code preferentially into non-shared "fast RAM" if it was available.
An illustration of a shared memory system of three processors. In computer science, shared memory is memory that may be simultaneously accessed by multiple programs with an intent to provide communication among them or avoid redundant copies. Shared memory is an efficient means of passing data between programs.
Video random-access memory (VRAM) is dedicated computer memory used to store the pixels and other graphics data as a framebuffer to be rendered on a computer monitor. [1] It often uses a different technology than other computer memory, in order to be read quickly for display on a screen.
When pure demand paging is used, pages are loaded only when they are referenced. A program from a memory mapped file begins execution with none of its pages in RAM. As the program commits page faults, the operating system copies the needed pages from a file, e.g., memory-mapped file, paging file, or a swap partition containing the page data ...
Virtual memory systems abstract between physical RAM and virtual addresses, assigning virtual memory addresses both to physical RAM and to disk-based storage, expanding addressable memory, but at the cost of speed. NUMA and SMP architectures optimize memory allocation within multi-processor systems. While these technologies dynamically manage ...
Virtual memory makes application programming easier by hiding fragmentation of physical memory; by delegating to the kernel the burden of managing the memory hierarchy (eliminating the need for the program to handle overlays explicitly); and, when each process is run in its own dedicated address space, by obviating the need to relocate program code or to access memory with relative addressing.
Shared memory is an efficient means of passing data between processes. In a shared-memory model, parallel processes share a global address space that they read and write to asynchronously. Asynchronous concurrent access can lead to race conditions, and mechanisms such as locks, semaphores and monitors can be used to avoid these.
Dual-ported video RAM (VRAM) is a dual-ported RAM variant of dynamic RAM (DRAM), which was once commonly used to store the Framebuffer in Graphics card, . Dual-ported RAM allows the CPU to read and write data to memory as if it were a conventional DRAM chip, while adding a second port that reads out data.