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.
Physical layerIn the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer: the layer most closely associated with the physical connection between devices. The physical layer provides an electrical, mechanical, and procedural interface to the transmission medium. The shapes and properties of the electrical connectors, the frequencies to broadcast on, the line code to use and similar low-level parameters, are specified by the physical layer.
Memory segmentationMemory segmentation is an operating system memory management technique of dividing a computer's primary memory into segments or sections. In a computer system using segmentation, a reference to a memory location includes a value that identifies a segment and an offset (memory location) within that segment. Segments or sections are also used in s of compiled programs when they are linked together into a and when the image is loaded into memory.
Read-only memoryRead-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM cannot be electronically modified after the manufacture of the memory device. Read-only memory is useful for storing software that is rarely changed during the life of the system, also known as firmware. Software applications (like video games) for programmable devices can be distributed as plug-in cartridges containing ROM.
Proximity sensorA proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact. A proximity sensor often emits an electromagnetic field or a beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal. The object being sensed is often referred to as the proximity sensor's target. Different proximity sensor targets demand different sensors. For example, a capacitive proximity sensor or photoelectric sensor might be suitable for a plastic target; an inductive proximity sensor always requires a metal target.
Proximity fuzeA proximity fuze (or fuse) is a fuze that detonates an explosive device automatically when it approaches within a certain distance of its target. Proximity fuzes are designed for elusive military targets such as airplanes and missiles, as well as ships at sea and ground forces. This sophisticated trigger mechanism may increase lethality by 5 to 10 times compared to the common contact fuze or timed fuze. Before the invention of the proximity fuze, detonation was induced by direct contact, a timer set at launch, or an altimeter.
Library technicianA library technician is a skilled library and information professional to perform the day-to-day functions of a library, and assists libraries in the acquisition, preparation, and organization of information. They also assist patrons in finding information. The widespread use of computerized information storage and retrieval systems has resulted in library technicians assisting in the handling of technical services (such as cataloguing). Especially in small village libraries, a library technician may be the only person (or one of only a few) staffing the library.
Out-of-order executionIn computer engineering, out-of-order execution (or more formally dynamic execution) is a paradigm used in most high-performance central processing units to make use of instruction cycles that would otherwise be wasted. In this paradigm, a processor executes instructions in an order governed by the availability of input data and execution units, rather than by their original order in a program. In doing so, the processor can avoid being idle while waiting for the preceding instruction to complete and can, in the meantime, process the next instructions that are able to run immediately and independently.
School libraryA school library (or a school library media center) is a library within a school where students, staff, and often, parents of a public or private school have access to a variety of resources. The goal of the school library media center is to ensure that all members of the school community have equitable access "to books and reading, to information, and to information technology." A school library media center "uses all types of media... is automated, and utilizes the Internet [as well as books] for information gathering.
Public libraryA public library is a library, most often a lending library, that is accessible by the general public and is usually funded from public sources, such as taxes. It is operated by librarians and library paraprofessionals, who are also civil servants. There are five fundamental characteristics shared by public libraries: they are generally supported by taxes (usually local, though any level of government can and may contribute); they are governed by a board to serve the public interest; they are open to all, and every community member can access the collection; they are entirely voluntary, no one is ever forced to use the services provided and they provide library and information services without charge.
