AmigaOS

Operating System Amigoid

See also: AmigaOS versions

Introduction

AmigaOS is the 32-bit Operating System for Amiga computers.

Originally, AmigaOS was designed entirely by the Amiga team but after Commodore bought the Amiga, it became obvious that it was running behind schedule. As a remedy, Commodore contracted the English company MetaComCo to port components of TripOS, a light-weight, little-known operating system written mostly in BCPL. The work became what is now known as Amiga's DOS library, or just "DOS". It is the IO foundation of AmigaOS (DOS is infamous for not fitting well into the AmigaOS design; the originally intended IO foundation was CAOS).

AmigaOS has many advanced features such as fully pre-emptive Multitasking, high flexibility (virtually all OS modules can be replaced or extended, even at run-time), a modern IO layer (with [File system]?s and Assign?s), Datatypes? (to provide generic access to all forms of formatted data), built-in localization and, last but not least, ARexx, its integrated scripting language. AmigaOS is very efficient: it needs relatively little hardware to run well (however, the performance-friendly minimalistic OS design has, in some instances, come to haunt AmigaOS). AmigaOS was also one of the first mainstream operating systems to use the desktop metaphor. The AmigaOS desktop is called Workbench.

The first versions of classic AmigaOS ran only on the Motorola 68k processors. Later, PowerPC kernel extensions were added (PowerUP and WarpOS) to support PPC accellerator cards. However, the basics of the OS remained with the 68k processor and only CPU-intensive subtasks such as image decoding were offloaded to the PPC CPU, introducing the dilemma of context switches between 68k CPU and PPC CPU. AmigaOS4 was the first version to entirely run on the PowerPC CPU, either in the AmigaOne or via PPC Accelerator cards, equalizing with MorphOS in that regard. The versions before AmigaOS4 are now commonly referred to as "classic AmigaOS".

CLONES

There are currently two operating systems that have branched off AmigaOS3 and compete with AmigaOS4, sometimes referred to as "amigoid" OSes or "amiga-like" OSes or "clones of AmigaOS" (technically speaking, they are not clones but aim to contain the AmigaOS3 API as a subset of their own, possibly extended API). These are:

• AROS, an Open Source endeveour to re-implement the AmigaOS3 API on several platforms. AROS is particularly strong on x86.
• MorphOS for the Pegasos PowerPC platform. MorphOS was the first Amiga-like OS to run entirely on the PPC CPU.

Weblinks

• Official site (little content)
• Unofficial site for "classic" AmigaOS (requirements, features etc for OS3.9, 3.5 and 3.1)
• IntuitionBase - has large OS4 section