Direct memory accessDirect memory access (DMA) is a feature of computer systems that allows certain hardware subsystems to access main system memory independently of the central processing unit (CPU). Without DMA, when the CPU is using programmed input/output, it is typically fully occupied for the entire duration of the read or write operation, and is thus unavailable to perform other work. With DMA, the CPU first initiates the transfer, then it does other operations while the transfer is in progress, and it finally receives an interrupt from the DMA controller (DMAC) when the operation is done.
Memory managementMemory management is a form of resource management applied to computer memory. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when no longer needed. This is critical to any advanced computer system where more than a single process might be underway at any time. Several methods have been devised that increase the effectiveness of memory management.
News serverA news server is a collection of software used to handle Usenet articles. It may also refer to a computer itself which is primarily or solely used for handling Usenet. Access to Usenet is only available through news server providers. End users often use the term "posting" to refer to a single message or file posted to Usenet. For articles containing plain text, this is synonymous with an article. For binary content such as pictures and files, it is often necessary to split the content among multiple articles.
