Redundancy

Redundancy or redundant may refer to:

Language and arts

Computer science and engineering

Data redundancy

In computer main memory, auxiliary storage and computer buses, data redundancy is the existence of data that is additional to the actual data and permits correction of errors in stored or transmitted data. The additional data can be simply a complete copy of the actual data, or only select pieces of data that allow detection of errors and reconstruction of lost or damaged data up to a certain level.

For example, by including additional data checksums, ECC memory is capable of detecting and correcting single-bit errors within each memory word, while RAID 1 combines two hard disk drives (HDDs) into a logical storage unit that allows stored data to survive a complete failure of one drive. Data redundancy can also be used as a measure against silent data corruption; for example, file systems such as Btrfs and ZFS use data and metadata checksumming in combination with copies of stored data to detect silent data corruption and repair its effects.

In database systems

Bearing a different nature, data redundancy also occurs in database systems that have a field repeated in two or more tables. Also called database normalization, it is usually used to improve performance of database queries (shorten the database response time), at the expense of complicating the database management, introducing the risk of corrupting the data, and increasing the required amount of storage.

Layoff

Layoff (in British and American English), is the temporary suspension or permanent termination of employment of an employee or (more commonly) a group of employees (collective layoff) for business reasons, such as when certain positions are no longer necessary or when a business slow-down occurs. In the UK, permanent termination due to elimination of a position is usually called redundancy.

Laidoff workers or displaced workers refers to workers who have lost or left their jobs because their employer has closed or moved, there was insufficient work for them to do, or their position or shift was abolished.

Originally the term layoff referred exclusively to a temporary interruption in work, as when factory work cyclically falls off. In late 20th and early 21st century North America, layoff usually means the permanent elimination of a position, requiring the addition of "temporary" to specify the original meaning.

Many synonyms such as downsizing exist, most of which are euphemisms or doublespeak and more abstract descriptions of the process, most of which can also be used for more inclusive processes than that of reducing the number of employees. Downsizing is defined as the "conscious use of permanent personnel reductions in an attempt to improve efficiency and/or effectiveness". Since the 1980s, downsizing has become increasingly common. Indeed, recent research on downsizing in the U.S., UK, and Japan suggests that downsizing is being regarded by management as one of the preferred routes to turning around declining organisations, cutting costs, and improving organisational performance, most often as a cost-cutting measure.