The Shuttle or small form factor (SFF) is a size description for motherboards on computers. Since these boards may be quite small, it is more common to find them in computing devices smaller than laptops. Unlike most computer form factors, the small form factor isn’t actually a specification—in this case, form factor describes any motherboard below a certain size. Since the definition is quite vague, but closely related to a common computing term, advertisers often misuse it. Even though they are so small, the majority of small form factor motherboards have all of the components common to larger boards.
The Shuttle company was one of the pioneers in small motherboards, and the Shuttle form factor was a term coined to describe its products. As time went one, other manufacturers began making small boards, and the term changed to small form factor, mostly to maintain the abbreviation. SFF motherboards are now made by a wide range of companies for a huge number of products.
In computing, a motherboard’s form factor generally refers to a specification for the motherboard. For instance, the advanced technology extended (ATX) motherboard is a common form factor found in full-size desktop computers. The form factor lays out the position of many of the components, ranging from the expansion slots to the screw holes. This allows components made by different companies to work together and fit inside the computer’s case.
In the case of small form factor, the term has a different meaning. In most cases, a SFF board is anything smaller than a micro-ATX motherboard. The SFF doesn’t lay out any specifications or ensure any form of compatibility. A SFF motherboard will always have a second designation that is its actual form factor. For instance, many “bookshelf computers” use a SFF motherboard with the mini-ITX form factor specification.
Since a small form factor board can be very small, it is often used in non-standard computers and computing devices. Small, or handheld, computers often use these boards. The most common computers in this class are bookshelf computers and tablets. Several types of self-governing computer components, such as standalone printing solutions or network accessible storage devices, use these boards to control their operations when not directed by a computer.
These boards are also used outside of basic computers as well. For instance, many home theater systems, digital cable boxes and digital video recorders have a SFF board that contains all the basic components of a desktop computer, just on a smaller scale. These boards are also common in complex handheld electronics like smartphones or handheld media players.