The aos sí, "ace shee", older form aes sídhe [eːs ˈʃiːðʲə]), "ays sheeth-uh") is the Irish term for a supernatural race in Irish mythology and Scottish mythology (usually spelled Sìth, however pronounced the same), comparable to the fairies or elves. They are said to live underground in fairy mounds, across the western sea, or in an invisible world that coexists with the world of humans. This world is described in the Book of Invasions (recorded in the Book of Leinster) as a parallel universe in which the aos sí walk amongst the living. In the Irish language, aos sí means "people of the mounds" (the mounds are known in Irish as "the sídhe"). In Irish literature the people of the mounds are also called daoine sídhe [ˈdiːnʲə ˈʃiːə]; in Scottish mythology they are daoine sìth. They are variously said to be the ancestors, the spirits of nature, or goddesses and gods.
Some secondary and tertiary sources, including well-known and influential authors such as W.B. Yeats, refer to aos sí simply as "the sídhe" (lit. "mounds").
AoS or AOS may refer to:
AOS was the name of a family of operating systems for Data General 16-bit Eclipse C, M, and S minicomputers, followed by AOS/VS and AOS/RT32 (1980) and later AOS/VS II (1988) for the 32-bit Eclipse MV line.
AOS/VS exploited the 8-ring protection architecture of the Eclipse MV hardware with ring 7 being the least privileged and ring 0 being the most privileged. The AOS/VS kernel ran in ring 0 and used ring-1 addresses for data structures related to virtual address translations. Ring 2 was unused and reserved for future use by the kernel. The Agent, which performed much of the system call validation for the AOS/VS kernel, as well as some I/O buffering and many compatibility functions, ran in ring 3 of each process. Ring 4 was used by various D.G. products such as the INFOS II DBMS. Rings 5 and 6 were reserved for use by user programs but rarely used except for large software such as the MV/UX inner-ring emulator and Oracle which used ring 5. All user programs ran in ring 7.
There are various ways in which calculators interpret keystrokes.
One can categorize calculators into two main types: 1) single-step or immediate execution calculators and 2) expression or formula calculators.
On a formula calculator one types in an expression and then presses 'Enter' to evaluate the expression. There are various systems for typing in an expression: infix, postfix, natural display, etc.
On an immediate execution calculator, the user presses a key for each operation, by pressing keys to calculate all the intermediate results, before the final value is shown.
With the immediate execution mode (also known as algebraic entry system (AES) or chain calculation mode) of operation each binary operation is executed as soon as the next operator is pressed, therefore the order of operations in a mathematical expression is not taken into account. Scientific calculators have buttons for brackets and these calculators can take order of operation into account. Also for unary operations like √ or x2 the number is entered first then the operator. Simple four-function calculators, such as those included with most operating systems, usually use this input method.