What is a Slot?


A slot is a narrow opening or groove, usually in the form of an elongated hole or channel. The word is often used informally as a synonym for hole, slit, or aperture, especially when the reference is to an opening in a door or wall. The word is also sometimes used as a generic term for any device that accepts cash or other media for activation and output of a specified number of credits, such as an electronic gaming machine.

In computer architecture, a slot is a hardware implementation of the operation issue and data path machinery surrounding a set of one or more execution units (also called functional units). The concept of slots is most commonly found in very long instruction word (VLIW) computers. In contrast to dynamically scheduled machines, where this notion of a slot is less obvious, in VLIW systems the relationship between an operation in an instruction and the pipeline that executes it is explicit.

You’ve checked in, made it through security and found your gate, only to find out you’re waiting for a slot. It’s frustrating, especially after spending time and money to get to the airport and through all that other travel nonsense. But what is a slot and why can’t you take off?