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 p ...

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also i ...

, 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 in 2002. It is free and open-source software under a BSD-like license.

History

A2 is the next generation of Native Oberon, the

x86 x86 (also known as 80x86 or the 8086 family) is a family of complex instruction set computer (CISC) instruction set architectures initially developed by Intel based on the Intel 8086 microprocessor and its 8088 variant. The 8086 was intr ...

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 Fairi ...

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

. 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 ...

, combined with a thread 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 In computer science, type safety and type soundness are the extent to which a programming language discourages or prevents type errors. Type safety is sometimes alternatively considered to be a property of facilities of a computer language; that is ...

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''. ...

, 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 ...

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 ...

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 learn ...

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

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 are ...

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 users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inst ...

(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 cl ...

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 hyperlinks 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 o ...

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