A form of core memory for data storage. The core is made of tiny ferrite rings threaded with wires that are magnetized by electrical current. The two possible polarities of magnetization were used to represent the binary values zero and one. Data are stored by magnetizing an array of cores in a particular combination of zeros and ones. Data are retrieved by sending electrical pulses to the specific array of cores holding the desired information. The pulses reverse the direction of magnetization in the cores, including output signals corresponding to the stored data.
This form of memory storage began in the 1950s and was widely used up through the 1970s. Core memory, which made forms of memory such as the magnetic drum obsolete, was rendered obsolete by semiconductor memory.
(n.) A fluid in which fine particles of iron, magnetite or cobalt are suspended, typically in an oil. A ferrofluid is superparamagnetic and can create liquid seals held in position by magnetic fields. One application of ferrofluids is to keep dust off of the drive shafts of magnetic disk drives. Ferrofluids were invented by NASA […]
To load an instruction or piece of data from memory into a CPU’s register. All instructions must be fetched before they can be executed. The time it takes to fetch an item is known as the fetch time or fetch cycle, and is measured in clock ticks.
- fetch cycle
See under instruction cycle.
- Fiber Optics
A technology that uses glass (or plastic) threads (fibers) to transmit data. A fiber optic cable consists of a bundle of glass threads, each of which is capable of transmitting messages modulated onto light waves. Fiber optics has several advantages over traditional metal communications lines: Fiber optic cables have a much greater bandwidth than metal […]
) (1) A space allocated for a particular item of information. A tax form, for example, contains a number of fields: one for your name, one for your Social Security number, one for your income, and so on. In database systems, fields are the smallest units of information you can access. In spreadsheets, fields are […]