In computing, a data segment (often denoted .data) is a portion of an object file or the corresponding virtual address space of a program that contains initialized static variables, that is, global variables and static local variables. The size of this segment is determined by the size of the values in the program's source code, and does not change at run time.
The data segment is read-write, since the values of variables can be altered at run time. This is in contrast to the read-only data segment (rodata segment or .rodata), which contains static constants rather than variables; it also contrasts to the code segment, also known as the text segment, which is read-only on many architectures. Uninitialized data, both variables and constants, is instead in the BSS segment.
Historically, to be able to support memory address spaces larger than the native size of the internal address register would allow, early CPUs implemented a system of segmentation whereby they would store a small set of indexes to use as offsets to certain areas. The Intel 8086 family of CPUs provided four segments: the code segment, the data segment, the stack segment and the extra segment. Each segment was placed at a specific location in memory by the software being executed and all instructions that operated on the data within those segments were performed relative to the start of that segment. This allowed a 16-bit address register, which would normally provide 64KiB (65536 bytes) of memory space, to access a 1MiB (1048576 bytes) address space.
DATA were an electronic music band created in the late 1970s by Georg Kajanus, creator of such bands as Eclection, Sailor and Noir (with Tim Dry of the robotic/music duo Tik and Tok). After the break-up of Sailor in the late 1970s, Kajanus decided to experiment with electronic music and formed DATA, together with vocalists Francesca ("Frankie") and Phillipa ("Phil") Boulter, daughters of British singer John Boulter.
The classically orientated title track of DATA’s first album, Opera Electronica, was used as the theme music to the short film, Towers of Babel (1981), which was directed by Jonathan Lewis and starred Anna Quayle and Ken Campbell. Towers of Babel was nominated for a BAFTA award in 1982 and won the Silver Hugo Award for Best Short Film at the Chicago International Film Festival of the same year.
DATA released two more albums, the experimental 2-Time (1983) and the Country & Western-inspired electronica album Elegant Machinery (1985). The title of the last album was the inspiration for the name of Swedish pop synth group, elegant MACHINERY, formerly known as Pole Position.
The word data has generated considerable controversy on if it is a singular, uncountable noun, or should be treated as the plural of the now-rarely-used datum.
In one sense, data is the plural form of datum. Datum actually can also be a count noun with the plural datums (see usage in datum article) that can be used with cardinal numbers (e.g. "80 datums"); data (originally a Latin plural) is not used like a normal count noun with cardinal numbers and can be plural with such plural determiners as these and many or as a singular abstract mass noun with a verb in the singular form. Even when a very small quantity of data is referenced (one number, for example) the phrase piece of data is often used, as opposed to datum. The debate over appropriate usage continues, but "data" as a singular form is far more common.
In English, the word datum is still used in the general sense of "an item given". In cartography, geography, nuclear magnetic resonance and technical drawing it is often used to refer to a single specific reference datum from which distances to all other data are measured. Any measurement or result is a datum, though data point is now far more common.
Return may refer to:
In retail, a return is the process of a customer taking previously purchased merchandise back to the retailer, and in turn receiving a refund in the original form of payment, exchange for another item (identical or different), or a store credit.
Many retailers will accept returns provided that the customer has a receipt as a proof of purchase, and that certain other conditions, which depend on the retailer's policies, are met. These may include the merchandise being in a certain condition (usually resellable if not defective), no more than a certain amount of time having passed since the purchase, and sometimes that identification be provided (though usually only if a receipt is not provided). In some cases, only exchanges or store credit are offered, again usually only without a receipt, or after an initial refund period has passed. Some retailers charge a restocking fee for non-defective returned merchandise, but typically only if the packaging has been opened.
While retailers are not usually required to accept returns, laws in many places require retailers to post their return policy in a place where it would be visible to the customer prior to purchase.
In finance, return is a profit on an investment. It comprises any change in value and interest or dividends or other such cash flows which the investor receives from the investment. It may be measured either in absolute terms (e.g., dollars) or as a percentage of the amount invested. The latter is also called the holding period return.
A loss instead of a profit is described as a negative return.
Rate of return is a profit on an investment over a period of time, expressed as a proportion of the original investment. The time period is typically a year, in which case the rate of return is referred to as annual return.
To compare returns over time periods of different lengths on an equal basis, it is useful to convert each return into an annual equivalent rate of return, or annualised return. This conversion process is called annualisation, described below.
Return on investment (ROI) is return per dollar invested. It is a measure of investment performance, as opposed to size (c.f. return on equity, return on assets, return on capital employed).