Data General AOS

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.

AOS

AoS or AOS may refer to:

Military, police and government

Schools and education

Science and academia

Calculator input methods

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.

Immediate execution

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.

AmigaOS 4

AmigaOS 4, (abbreviated as OS4 or AOS4), is a line of Amiga operating systems which runs on PowerPC microprocessors. It is mainly based on AmigaOS 3.1 source code developed by Commodore, and partially on version 3.9 developed by Haage & Partner. "The Final Update" (for OS version 4.0) was released on 24 December 2006 (originally released in April 2004) after five years of development by the Belgian company Hyperion Entertainment under license from Amiga, Inc. for AmigaOne registered users.

History

During the five years of development, purchasers of AmigaOne machines could download pre-release versions of AmigaOS 4.0 from Hyperion's repository as long as these were made available.

On 20 December 2006, Amiga, Inc abruptly terminated the contract with Hyperion Entertainment to produce or sell AmigaOS 4. Nevertheless, AmigaOS 4.0 was released commercially for Amigas with PowerUP accelerator cards in November 2007 (having been available only to developers and beta-testers until then). The Italian computer company ACube Systems has announced Sam440ep and Sam440ep-flex motherboards, which are AmigaOS 4 compatible. Also, a third party bootloader, known as the "Moana", was released by Acube on torrent sites; it allows installation of the Sam440ep version of OS4 to Mac Mini G4's. However this is both unofficial and unsupported as of today, and very incomplete, especially regarding drivers. During the judicial procedure (between Hyperion and Amiga, Inc), OS4 was still being developed and distributed.