A2 (formerly named Active Object System (AOS), and then Bluebottle) is a modular,

object-oriented Object-oriented programming (OOP) is a programming paradigm based on the concept of " objects", which can contain data and code. The data is in the form of fields (often known as attributes or ''properties''), and the code is in the form of ...

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...

, with some unconventional features, including automatic garbage-collected memory management, and a

zooming user interface In computing, a zooming user interface or zoomable user interface (ZUI, pronounced zoo-ee) is a graphical environment where users can change the scale of the viewed area in order to see more detail or less, and browse through different document ...

. It was developed originally at

ETH Zurich (colloquially) , former_name = eidgenössische polytechnische Schule , image = ETHZ.JPG , image_size = , established = , type = Public , budget = CHF 1.896 billion (2021) , rector = Günther Dissertori , president = Joël Mesot , a ...

in 2002. It is

free and open-source software Free and open-source software (FOSS) is a term used to refer to groups of software consisting of both free software and open-source software where anyone is freely licensed to use, copy, study, and change the software in any way, and the source ...

under a BSD-like license.

History

A2 is the next generation of

Native Oberon The Oberon System is a modular, single-user, single-process, multitasking operating system written in the programming language Oberon. It was originally developed in the late 1980s at ETH Zurich. The Oberon System has an unconventional visual text ...

, the x86 PC version of

Niklaus Wirth Niklaus Emil Wirth (born 15 February 1934) is a Swiss computer scientist. He has designed several programming languages, including Pascal, and pioneered several classic topics in software engineering. In 1984, he won the Turing Award, generally ...

's operating system

Oberon Oberon () is a king of the fairies in medieval and Renaissance literature. He is best known as a character in William Shakespeare's play ''A Midsummer Night's Dream'', in which he is King of the Fairies and spouse of Titania, Queen of the Fair ...

. Out of print
Electronic reprint.
/ref> It is small, fast, supports

multiprocessing Multiprocessing is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor or the ability to allocate tasks between them. There ar ...

computers, and provides soft

real-time computing Real-time computing (RTC) is the computer science term for hardware and software systems subject to a "real-time constraint", for example from event to system response. Real-time programs must guarantee response within specified time constra ...

operation. It is entirely written in an upward-compatible dialect of the programming language

named

Active Oberon Active Oberon is a general purpose programming language developed during 1996-1998 by the group around Niklaus Wirth and Jürg Gutknecht at the Swiss Federal Institute of Technology in Zürich (ETH Zurich). It is an extension of the programming ...

. Both languages are members of the Pascal family, along with

Modula-2 Modula-2 is a structured, procedural programming language developed between 1977 and 1985/8 by Niklaus Wirth at ETH Zurich. It was created as the language for the operating system and application software of the Lilith personal workstation. It w ...

. A2's design allows developing efficient systems based on ''active objects'' which run directly on hardware, with no mediating interpreter or

virtual machine In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized har ...

. Active objects represent a combination of the traditional

object-oriented programming Object-oriented programming (OOP) is a programming paradigm based on the concept of " objects", which can contain data and code. The data is in the form of fields (often known as attributes or ''properties''), and the code is in the form of ...

(OOP) model of an

object Object may refer to: General meanings * Object (philosophy), a thing, being, or concept ** Object (abstract), an object which does not exist at any particular time or place ** Physical object, an identifiable collection of matter * Goal, an ai ...

, combined with a

thread Thread may refer to: Objects * Thread (yarn), a kind of thin yarn used for sewing ** Thread (unit of measurement), a cotton yarn measure * Screw thread, a helical ridge on a cylindrical fastener Arts and entertainment * ''Thread'' (film), 2016 ...

that executes in the context of that object. In the Active Oberon implementation, an active object may include activity of its own, and of its ancestor objects. Other differences between A2 and more mainstream operating systems is a very

minimalist In visual arts, music and other media, minimalism is an art movement that began in post–World War II in Western art, most strongly with American visual arts in the 1960s and early 1970s. Prominent artists associated with minimalism include Do ...

design, completely implemented in a type-safe language, with

automatic memory management In computer science, garbage collection (GC) is a form of automatic memory management. The ''garbage collector'' attempts to reclaim memory which was allocated by the program, but is no longer referenced; such memory is called ''garbage''. G ...

, combined with a powerful and flexible set of primitives (at the level of

programming language A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language. The description of a programming l ...

and

runtime system In computer programming, a runtime system or runtime environment is a sub-system that exists both in the computer where a program is created, as well as in the computers where the program is intended to be run. The name comes from the compile t ...

) for synchronising access to the internal properties of objects in competing

execution Capital punishment, also known as the death penalty, is the state-sanctioned practice of deliberately killing a person as a punishment for an actual or supposed crime, usually following an authorized, rule-governed process to conclude that t ...

contexts. Above the

kernel Kernel may refer to: Computing * Kernel (operating system), the central component of most operating systems * Kernel (image processing), a matrix used for image convolution * Compute kernel, in GPGPU programming * Kernel method, in machine lea ...

layer, A2 provides a flexible set of modules providing unified abstractions for devices and services, such as

file system In computing, file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one lar ...

user interface In the industrial design field of human–computer interaction, a user interface (UI) is the space where interactions between humans and machines occur. The goal of this interaction is to allow effective operation and control of the machine f ...

computer network A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections ar ...

connections, media

codec A codec is a device or computer program that encodes or decodes a data stream or signal. ''Codec'' is a portmanteau of coder/decoder. In electronic communications, an endec is a device that acts as both an encoder and a decoder on a signal or ...

s, etc.

User interface

Bluebottle replaced the older Oberon OS's unique

text-based user interface In computing, text-based user interfaces (TUI) (alternately terminal user interfaces, to reflect a dependence upon the properties of computer terminals and not just text), is a retronym describing a type of user interface (UI) common as an ear ...

(TUI) with a

(ZUI), which is significantly more like a conventional

graphical user interface The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows User (computing), users to Human–computer interaction, interact with electronic devices through graphical icon (comp ...

(GUI). Like Oberon, though, its user interface supports a ''

point and click Point and click are the actions of a computer user moving a pointer to a certain location on a screen (''pointing'') and then pressing a button on a mouse, usually the left button (''click''), or other pointing device. An example of point and c ...

interface metaphor In user interface design, an interface metaphor is a set of user interface visuals, actions and procedures that exploit specific knowledge that users already have of other domains. The purpose of the interface metaphor is to give the user instanta ...

to execute commands directly from text, similar to clicking

hyperlink In computing, a hyperlink, or simply a link, is a digital reference to data that the user can follow or be guided by clicking or tapping. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text ...

s in a

web browser A web browser is application software for accessing websites. When a user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's screen. Browsers are used on ...

References

External links

Official website
ETH Zürich
A2 Operating System & Active Oberon community in Telegram

An application in industrial control at Radiar

A2 user guide and applications description

A short movie showing a programming technique and the Bluebottle OS
* Archived , ETH Zürich * Archive
Oberon Language Genealogy
* Archive
Oberon Community Platform - Wiki & Forum
{{Wirth Free software operating systems

History

User interface

See also

References

External links