AmigaOS
A screenshot of AmigaOS 4.0
Website	amiga.com
Company/ developer	Commodore International (1.0-3.1) Haage & Partner (3.5-3.9) Hyperion Entertainment (4.0)
OS family	Amiga OS
Source model	Closed source
Latest stable release	4.0 (First Update) version / July 18, 2007 (2007-07-18), 266 days ago
Kernel type	Atypical microkernel
License	Proprietary
Working state	Current

AmigaOS is the default native operating system of the Amiga personal computer. It was developed first by Commodore International, and initially introduced in 1985 with the Amiga 1000. It ran on the Motorola 68k series of 32-bit microprocessors, except for AmigaOS 4 which runs on PowerPC microprocessors. Amiga Logo (1985) This is a copyrighted and/or trademarked logo. ... There have been many different versions of the AmigaOS operating system during its two decades of history. ... A website (alternatively, Web site or web site) is a collection of Web pages, images, videos or other digital assets that is hosted on one or several Web server(s), usually accessible via the Internet, cell phone or a LAN. A Web page is a document, typically written in HTML... The term software company could be applied to: a) a company that produces software, distributes software from a third party, or provides services such as custom software development. ... For other uses, see Software developer (disambiguation). ... Commodore, the commonly used name for Commodore International, was an American electronics company based in West Chester, Pennsylvania which was a vital player in the home/personal computer field in the 1980s. ... Hyperion Entertainment developes Amiga, Linux and Macintosh games. ... The text below is generated by a template, which has been proposed for deletion. ... is the 199th day of the year (200th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... A kernel connects the application software to the hardware of a computer. ... Graphical overview of a microkernel A microkernel is a minimal computer operating system kernel providing only basic operating system services (system calls), while other services (commonly provided by kernels) are provided by user-space programs called servers. ... A software license is a legal agreement which may take the form of a proprietary or gratuitous license as well as a memorandum of contract between a producer and a user of computer software. ... Proprietary software is software with restrictions on copying and modifying as enforced by the proprietor. ... An operating system (OS) is the software that manages the sharing of the resources of a computer and provides programmers with an interface used to access those resources. ... This article is about the family of home computers. ... Commodore, the commonly used name for Commodore International, was an American electronics company based in West Chester, Pennsylvania which was a vital player in the home/personal computer field in the 1980s. ... This article is about the year. ... The A1000, or Commodore Amiga 1000, was Commodores initial Amiga personal computer, introduced on July 24, 1985 at the Lincoln Center in New York City. ... Motorola Inc. ... The Motorola 680x0/0x0/m68k/68k/68K family of CISC microprocessor CPU chips were 32-bit from the start, and were the primary competition for the Intel x86 family of chips in personal computers of the 1980s and early 1990s. ... 32-bit is a term applied to processors, and computer architectures which manipulate the address and data in 32-bit chunks. ... A microprocessor incorporates most or all of the functions of a central processing unit (CPU) on a single integrated circuit (IC). ... PowerPC is a RISC microprocessor architecture created by the 1991 Apple–IBM–Motorola alliance, known as AIM. Originally intended for personal computers, PowerPC CPUs have since become popular embedded and high-performance processors as well. ...

On top of a preemptive multitasking kernel called Exec, it includes an abstraction of the Amiga's unique hardware, a disk operating system called AmigaDOS, a windowing system API called Intuition and a graphical user interface called Workbench. A command line interface is also available. Pre-emptive multitasking is a form of multitasking in which processes are not allowed to take an indefinitely long time to complete execution in the CPU. Each process, in turn, is granted a portion of CPU time (usually called a time slice, on the order of milliseconds). ... A kernel connects the application software to the hardware of a computer. ... API and Api redirect here. ... Amiga Workbench (1985) The Amiga computer was launched by Commodore in 1985 with a GUI called Workbench based on an internal engine which drives all the input events called Intuition, and developed almost entirely by RJ Mical. ... GUI redirects here. ... Amiga Workbench (1985) Workbench is the name given to both the core AmigaOS software that is not stored in the Kickstart ROM (the Workbench disk), and also the native graphical shell for the Amiga computer. ... This article or section does not adequately cite its references or sources. ...

Components

AmigaOS can be divided into two parts: the Kickstart (ROM) and Workbench disks. Versions of Kickstart and Workbench used to be released together, for use with each other. But since Workbench 3.5, the first release after Commodore International stopped development, AmigaOS became software-only, standardising on Kickstart version 3.1 in ROM. Read-only memory (usually known by its acronym, ROM) is a class of storage media used in computers and other electronic devices. ... Commodore, the commonly used name for Commodore International, was an American electronics company based in West Chester, Pennsylvania which was a vital player in the home/personal computer field in the 1980s. ...

Kickstart

Kickstart is the bootstrap ROM. On the first Amiga model, the A1000, it was loaded from disk into a special section of memory called the writable control store (WCS). Eventually Kickstart was embedded in a ROM chip inside later Amiga models. The Amiga 1000 could also be modified to take these chips. Amiga kickstart screenshot This is a screenshot of copyrighted computer software. ... A floppy disk is a data storage device that is composed of a disk of thin, flexible (floppy) magnetic storage medium encased in a square or rectangular plastic shell. ... In computing, booting (booting up) is a bootstrapping process that starts operating systems when the user turns on a computer system. ... This article is about the family of home computers. ... The A1000, or Commodore Amiga 1000, was Commodores initial Amiga personal computer, introduced on July 24, 1985 at the Lincoln Center in New York City. ...

Kickstart contains the code needed to boot the standard Amiga hardware and any Autoconfig expansion hardware. The Kickstart also contained many stock parts of the Amiga's operating system, such as Exec, Intuition and the core of AmigaDOS. This meant that a powered-on Amiga already had a lot of the essential parts of the operating system available. Later versions of the Kickstart contained drivers for IDE and SCSI controllers, PC card ports and various other hardware that came built into Amigas. It can be compared to the BIOS plus the main Windows kernel in IBM PCs, however it has far more functionality available at boot time — the full windowing environment, for example. AutoConfig is a feature of Amiga computers which gives features similar to todays Plug and Play, although it was introduced in 1985 with the A1000, years before Windows 95. ... Amiga Workbench (1985) The Amiga computer was launched by Commodore in 1985 with a GUI called Workbench based on an internal engine which drives all the input events called Intuition, and developed almost entirely by RJ Mical. ... ATA cables: 40 wire ribbon cable top, 80 wire ribbon cable bottom Advanced Technology Attachment (ATA), is a standard interface for connecting storage devices such as hard disks and CD-ROM drives inside personal computers. ... Scuzzy redirects here. ... The PCMCIA is the Personal Computer Memory Card International Association, an industry trade association that creates standards for notebook computer peripheral devices. ... For other uses, see Bios. ... 1. ... IBM PC (IBM 5150) with keyboard and green screen monochrome monitor (IBM 5151), running MS-DOS 5. ...

With third party software, it is possible to have a different Kickstart loaded in RAM and to use it instead of the ROM one — for example Kickstart 1.3 may be loaded in order to run old games incompatible with Kickstart 2.0 and higher. These programs are called softkickers. There are also hardware Kickstart switchers which allow you to have more than one set of Kickstart chips inside the computer, which are selectable either by a switch or a keyboard shortcut when you first turn the machine on. Software redirects here. ...

MMU-enabled Amigas typically loaded a copy of kickstart from a file on disk and passed control to it at cold-boot time. Subsequent warm-boots would reuse the already-loaded copy of kickstart, reducing boot time. An Amiga 3000 could fully warm-boot in 7 seconds; cold-boot in 11 seconds. This 68451 MMU could be used with the Motorola 68010 MMU, short for memory management unit or sometimes called paged memory management unit as PMMU, is a class of computer hardware components responsible for handling memory accesses requested by the CPU. Among the functions of such devices are the translation...

Workbench

Main article: Workbench (AmigaOS)

Workbench is the name given to both the core operating system software that is not stored in the Kickstart ROM (the "Workbench disk"), and also the native graphical shell for the Amiga computer. The Workbench environment does not have to be loaded for software to run. In fact, to take over the Amiga hardware and keep all memory and resources to themselves, many games boot directly from Kickstart (using a custom bootblock on the floppy disk). Amiga Workbench (1985) Workbench is the name given to both the core AmigaOS software that is not stored in the Kickstart ROM (the Workbench disk), and also the native graphical shell for the Amiga computer. ... It has been suggested that this article or section be merged into Shell_(computing). ... This article is about the family of home computers. ... The bootblock is a small portion of software code read from a specific area of boot device after control is handed to it by the BIOS (or similar structure dependending of system architecture involved, eg: OBP on Sun SPARC systems). ... A floppy disk is a data storage device that is composed of a disk of thin, flexible (floppy) magnetic storage medium encased in a square or rectangular plastic shell. ...

Amiga Workbench 1.3 (1988)

As the name suggests, the metaphor of a workbench is used, rather than a desktop; directories are depicted as drawers, executable files are tools, data files are projects and GUI widgets are gadgets. In many other aspects the interface resembles Mac OS, with the main desktop showing icons of inserted disks and hard drive partitions, and a single menu bar at the top of every screen. Unlike the Macintosh, the standard Amiga mouse has two buttons – the right mouse button operates the pull-down menus, with a Macintosh-style "release to select" mechanism. Amiga_Workbench_1_3 large version from http://www. ... Amiga_Workbench_1_3 large version from http://www. ... This article is about the family of home computers. ... Amiga Workbench (1985) Workbench is the name given to both the core AmigaOS software that is not stored in the Kickstart ROM (the Workbench disk), and also the native graphical shell for the Amiga computer. ... This article is about metaphor in literature and rhetoric. ... AmigaOS is the default native operating system of the Amiga and AmigaOne personal computers. ... This article relates to both the original Classic Mac OS as well as Mac OS X, Apples more recent operating system. ...

A unique feature of Workbench is multiple screens. These are conceptually similar to X Window System virtual desktops or workspaces, but are generated dynamically by application programs as necessary. Each screen can have a different resolution and colour depth. A gadget in the top-right corner of the screen allows screens to be cycled — as the OS stores all screens in memory simultaneously, redrawing is instantaneous. Screens can also be dragged up and down by their title bars. On older Amigas this functionality was provided by the custom chipsets specially designed for the platform, but since AmigaOS4 a new technique is adopted and the screens are draggable in any direction. Drag and drop between different screens is possible too. “X11” redirects here. ...

Underlying the Workbench is the Intuition windowing system. This controls and draws screens, windows and gadgets, and handles input from the keyboard and mouse, passing messages to programs.

Workbench 2.0 user interface improvements

Amiga Workbench 2.0 (1991)

Until Workbench 2.0, there was no unified look and feel design standard — application developers had to write their own widgets (both buttons and menus), with Intuition providing minimal support. With Workbench 2.0 came gadtools.library, which provided standard widget sets, and the Amiga User Interface Style Guide, which explained how applications should be laid out for consistency. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... This article is about the family of home computers. ... Amiga Workbench (1985) Workbench is the name given to both the core AmigaOS software that is not stored in the Kickstart ROM (the Workbench disk), and also the native graphical shell for the Amiga computer. ... Look and feel refers to design aspects of a graphical user interface - in terms of both colours, shapes, layout, typefaces, etc (the look); and, the behaviour of dynamic elements such as buttons, boxes, and menus (the feel). It is used in reference to both software and websites. ...

Workbench 2.0 also added support for public screens. Instead of the Workbench screen being the only shareable screen, applications could create their own named screens to share with other applications.

Workbench 2.0 introduced AmigaGuide, a simple hypertext markup scheme and browser, for providing online help inside applications. It also introduced Installer, a standard software installation program, driven by a LISP-like scripting language. Amigaguide is a hypertext document file format designed for the Amiga, files are stored in ASCII so it is possible to read and edit a file without the need for special software. ... In computing, hypertext is a user interface paradigm for displaying documents which, according to an early definition (Nelson 1970), branch or perform on request. ... For the programming language, see Lisp (programming language). ...

Finally, Workbench 2.0 rectified the problem of developers hooking directly into the input-events stream to capture keyboard and mouse movements, often locking up the whole system. Workbench 2.0 provided Commodities, a standard interface for modifying or scanning input events. This included a standard method for specifying global "hotkey" key-sequences, and a Commodities Exchange registry for the user to see what commodities were running. Hooking in programming is a technique employing so called hooks to make a chain of procedures as a handler. ...

AmigaDOS

Main article: AmigaDOS

AmigaDOS provides the disk operating system portion of the AmigaOS. This includes file systems, file and directory manipulation, the command line interface, file redirection, console windows, and so on. AmigaOS is the default native operating system of the Amiga and AmigaOne personal computers. ... Disk Operating System (specifically) and disk operating system (generically), most often abbreviated as DOS (not to be confused with the DOS family of disk operating systems for the IBM PC compatible platform), refer to operating system software used in most computers that provides the abstraction and management of secondary storage... For library and office filing systems, see Library classification. ... This article or section does not adequately cite its references or sources. ...

In AmigaOS 1.x, the AmigaDOS portion was based on a TRIPOS port by MetaComCo, written in BCPL. Considerable amounts of functionality was only available by interfacing with libraries written in BCPL, which proved a difficult and error-prone task from C and other languages because of BCPL's ideosyncratic pointer mechanism. The original amigados CLI utilities written in BCPL also had the disadvantage of occupying a relatively large memory footprint, and ran slower than equivalent C. The University of Cambridge, England, divides the different kinds of honours bachelors degree by Tripos, a word which has an obscure etymology, but which may be traced to the three-legged stool candidates once used to sit on when taking oral examinations. ... MetaComCo was a company started in 1984 and based in Bristol, England. ... BCPL (Basic Combined Programming Language) is a computer programming language that was designed by Martin Richards of the University of Cambridge in 1966; it was originally intended for use in writing compilers for other languages. ... It has been suggested that this article or section be merged into Command line interface. ...

The third-party AmigaDOS Resource Project^[1] (ARP, formerly the AmigaDOS Replacement Project^[2]), a project begun by Amiga developer Charlie Heath, replaced many of the BCPL utilities with smaller and often more sophisticated equivalents written in C and assembler, and provided a wrapper library, arp.library, which eliminated the interfacing problems in applications by automatically performing conversions from native pointers (such as those used by C or assembler) to BCPL equivalents and vice versa for all AmigaDOS functions. ARP also provided one of the first standardized file requesters for the Amiga, and introduced the use of more friendly UNIX-style wildcard (globbing) functions in command line parameters. Other innovations were an improvement in the range of date formats accepted by commands and the facility to make a command resident, so that it only needs to be loaded into memory once and remains in memory to reduce the cost of loading in subsequent uses. In computing, a File dialog (Also called File Selector/Chooser, or open and save dialog) is a dialog box that allows users to choose a file from the file system. ... glob() is a Unix library function that expands file names using a pattern matching notation reminiscent of regular expression syntax but without the expressive power of true regular expressions. ...

From AmigaOS 2.x onwards, AmigaDOS was rewritten in C and Assembler, retaining full 1.x BCPL program compatibility, and incorporated most of ARP into the OS. C is a general-purpose, block structured, procedural, imperative computer programming language developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. ... See the terminology section, below, regarding inconsistent use of the terms assembly and assembler. ...

Partitions and physical drives are typically referred to as DF0: (floppy drive 0), DH0: (hard drive 0), etc. However, unlike many operating systems, outside of built-in devices like DF0: these names are totally arbitrary; for example a hard disk partition could be named HARDDISK: or A: or HD0: when it was partitioned. Volume names have the same format as device names, so a disk partition on device DH0: might have the volume name Boot:. In addition, virtual volume names could be set with the "assign" command to any directory or device; for example programs often assigned a virtual volume name to their installation directory; an example might be FooBarWriter assigning FooBar: to DH0:Productivity/FooBarWriter. This allows for easy relocation of installed programs.

Graphics

Up to version 3, AmigaOS only supported the native Amiga graphics chipset, via graphics.library. This led developers to avoid OS functionality for drawing, and go straight for the underlying hardware. Third-party graphics cards were only supported via unofficial solutions. The ideal situation, where the AmigaOS could directly support any graphics system, was termed retargetable graphics (RTG) [1]. Release 3.1 included some support for third party graphics cards, such as the Picasso. With AmigaOS 3.5, some RTG systems were bundled with the OS, allowing the use of common hardware cards other than the native Amiga chipsets. The main RTG systems are CyberGraphX, Picasso 96 and EGS. The Original Chip Set (OCS) was a chipset used in the earliest Commodore Amiga computers. ... This is the standard retargetable graphics API available for the Amigoid OSs. ... EGS is a three-letter abbreviation that may refer to: Edmonton Geological Society Edwards Graphics Supplies Ltd. ...

The Amiga did not have any official 3D graphics capability, so it had no standard 3D graphics interface. Graphics card manufacturers provided their own standards, which include MiniGL, Warp3D, StormMesa (agl.library) and CyberGL. VideoScape 3D was one of the earliest 3D rendering & animation systems, as well as TrueSpace 3D. The rewrite of this article is being devised at Talk:3D computer graphics/Temp. ... MiniGL is a cut-down version of the OpenGL 3D graphics API. It was developed by id Software in order to provide a cross-platform hardware abstraction layer for their Quake series games, the first to directly support acceleration on graphics cards. ... Mesa 3D is a free software graphics library, initially developed by Brian Paul in August 1993, that provides a generic OpenGL implementation for rendering three-dimensional graphics on multiple platforms. ... trueSpace is 3D computer graphics and animation software developed by Caligari Corporation. ...

Likewise, while the Amiga is well known for its ability to easily genlock with video, it had no built in video capture interface. Third party interfaces included DigiView [2], VHI (Video Hardware Interface) by IOSPIRIT GmbH, tv.library by Elbox Computer and tvcard.library by Guido Mersmann. Genlock (for Generator Lock) is a common technique where the video output of one source, or a specific reference signal, is used to synchronize other television picture sources together. ... Video capture usually refers to the various methods of capturing video on a computer. ...

Audio

Up to version 3.1, AmigaOS only supported the original Amiga chipset's sound capabilities, via audio.device. Support for third-party audio cards was vendor-dependent, until the creation and adoption of AHI [3] as a de facto standard. AmigaOS itself did not support MIDI until 3.1 when Roger Dannenberg's camd.library was adapted as the standard MIDI API. Commodore's version of camd.library also included a built in driver for the serial port. The later open source version of camd.library by Kjetil Matheussen did not provide a built in driver for the serial port, but provided an external driver instead. Musical Instrument Digital Interface, or MIDI, is a system designed to transmit information between electronic musical instruments. ...

Speech synthesis

The original Amiga was launched with speech synthesis software, developed by Softvoice, Inc. [4] This could be broken into three main components: narrator.device, which could play and modulate all phonemes used in American English, translator.library, which could translate English text to American English phonemes, and the SPEAK: handler, which command-line users could redirect output to, to have it spoken. Speech synthesis is the artificial production of human speech. ... In human language, a phoneme is the theoretical representation of a sound. ... For other uses, see American English (disambiguation). ...

In the original 1.x releases, a Say program in Utilities and a basic demo was also included with AmigaBASIC programming examples. AmigaBASIC was a BASIC implementation for the Amiga, designed by Microsoft. ...

The speech synthesiser was occasionally used in third-party programs, often educational software. The word processors Prowrite and Excellence! could read out documents using the synthesiser.

Despite the limitation on the narrator.device's phonemes, Francesco Devitt wrote a new version of translator.library which could translate any language to phonemes, given a set of rules for that language, and thus provided multilingual speech synthesis. [5]

ARexx

Main article: ARexx

The Amiga OS had support for the Rexx language. It was called ARexx (short for "Amiga Rexx") and was a script language which allowed for full OS scripting, similar to AppleScript, intra-application scripting, similar to VBA in Microsoft Office, as well as inter-program communication. Having a single scripting language for any application on the operating system was beneficial to users, instead of having to learn a new language for each application. ARexx is the Amiga version of scripting language REXX by IBM. It has been not licensed from IBM, but it is a version written by Bill Hawes who ported REXX to the Amiga, with many special Amiga features. ... REXX (REstructured eXtended eXecutor) is an interpreted programming language which was developed at IBM. It is a structured high-level programming language which was designed to be both easy to learn and easy to read. ... AppleScript is a scripting language devised by Apple, Inc. ... Visual Basic for Applications (VBA) is an implementation of Microsofts Visual Basic, an event driven programming language and associated integrated development environment (IDE) which is built into most Microsoft Office applications. ... Microsoft Office is an office suite from Microsoft for Microsoft Windows and Apple Mac OS X operating systems. ...

Programs could listen on an "ARexx port" for string messages. These messages could then be interpreted by the program in a similar fashion to a user pushing buttons. For example, an ARexx script when run in an e-mail program, could save the currently displayed email and invoke an external program which could extract and process information and then invoke a viewer program. This allowed applications to control other applications by sending data back and forth directly with memory handles instead of saving files to disk then reloading.

RAM disk

The Amiga OS has a dynamically-sized RAM disk, which resizes itself automatically to its contents. Starting with AmigaOS 2.x, operating System configuration files were loaded into the RAM disk on boot, greatly speeding operating system usage. Other files could be copied to the RAM disk like any standard device for quick modification and retrieval. Also beginning in AmigaOS 2.x, the RAM disk supported file-change notification, which was mostly used to monitor prefs files for changes.

The Amiga OS also has support for a fixed-capacity recoverable RAM disk, which functions as a standard RAM disk, but can maintain its contents on restart. It was commonly called RAD disk and it can function as a boot disk (with boot sector).

Technical overview

John C. Dvorak stated in 1996: John C. Dvorak in July 2007 John Charles Dvorak [1] (born 1952 in Los Angeles, California) is an American columnist and broadcaster in the areas of technology and computing. ...

The AmigaOS "remains one of the great operating systems of the past 20 years, incorporating a small kernel and tremendous multitasking capabilities the likes of which have only recently been developed in OS/2 and Windows NT. The biggest difference is that the AmigaOS could operate fully and multitask in as little as 250 K of address space. Even today, the OS is only about 1MB in size. And to this day, there is very little a memory-hogging CD-ROM-loading OS can do the Amiga can't. Tight code — there's nothing like it.
I've had an Amiga for maybe a decade. It's the single most reliable piece of equipment I've ever owned. It's amazing! You can easily understand why so many fanatics are out there wondering why they are alone in their love of the thing. The Amiga continues to inspire a vibrant — albeit cultlike — community, not unlike that which you have with Linux, the Unix clone."^[3] Multitasking may refer to any of the following: Computer multitasking - the apparent simultaneous performance of two or more tasks by a computers central processing unit. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Windows NT (New Technology) is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. ...

Libraries and devices

The main modularisation technique in AmigaOS is based on dynamically-loaded shared libraries, either stored as a file on disk with a ".library" filename extension, or stored in the Kickstart ROM. All libraries are accessed via an indirect jump table, which is always stored in RAM. That way, every library function can be patched or hooked at run-time, even if the library is stored in ROM. Modularity is a concept that has applications in the contexts of computer science, particularly programming, as well as cognitive science in investigating the structure of mind. ... Illustration of an application which may use libvorbisfile. ... In computer science, a jump table is a list of the addresses of a set of routines which can be selected by number. ... In computing, a patch is a small piece of software designed to update or fix problems with a computer program or its supporting data. ... Hooking in programming is a technique employing so called hooks to make a chain of procedures as a handler. ...

The most important library in AmigaOS is exec.library, which can be considered a microkernel, as well as a library. It acts as a scheduler for tasks running on the system, providing pre-emptive multitasking with prioritised round-robin scheduling. Exec also provides access to other libraries and high-level inter-process communication via message passing. (Other microkernels have had performance problems because of the need to copy messages between address spaces. Since the Amiga has only one address space, Exec message passing is quite efficient.) The only fixed memory address in the Amiga software (address 4) is a pointer to exec.library, which can then be used to access other libraries. Exec was designed and implemented by Carl Sassenrath. Graphical overview of a microkernel A microkernel is a minimal computer operating system kernel providing only basic operating system services (system calls), while other services (commonly provided by kernels) are provided by user-space programs called servers. ... For disk scheduling, see I/O scheduling. ... Pre-emptive multitasking is a form of multitasking. ... Round-robin is one of the simplest scheduling algorithms for processes in an operating system, which assigns time slices to each process in equal portions and in order, handling all processes as having the same priority. ... Inter-Process Communication (IPC) is a set of techniques for the exchange of data between two or more threads in one or more processes. ... In computer science, message passing is a form of communication used in concurrent programming, parallel programming, object-oriented programming, and interprocess communication. ... Carl Sassenrath created Exec, a major component of the Amigas Operating System, as well as the REBOL programming language. ...

Unlike traditional operating systems, the exec kernel does not run "privileged". Contemporary operating systems for the 68000 such as Atari TOS and SunOS used trap instructions for invoking kernel functions. This made the kernel functions run in the 68000's supervisor mode, while user software ran in the unprivileged user mode. By contrast, exec function calls are made with the library jump table, and the kernel code normally executes in user mode. Whenever supervisor mode is needed, either by the kernel or user programs, the library functions Supervisor() or SuperState() are used. Atari ST GEM desktop The Operating System (TOS) was the operating system of the Atari ST range of computers. ... SunOS was the version of the UNIX operating system developed by Sun Microsystems for their workstations and server systems until the early 1990s. ... Exception handling is a programming language construct or computer hardware mechanism designed to handle the occurrence of some condition that changes the normal flow of execution. ...

Device drivers are also libraries, but they implement a standardised interface. Applications do not usually call devices directly as libraries, but use the exec.library I/O functions to indirectly access them. Like libraries, devices are either files on disk (with the ".device" extension), or stored in the Kickstart ROM. A device driver, or software driver is a computer program allowing higher-level computer programs to interact with a computer hardware device. ...

Handlers, AmigaDOS and filesystems

The higher-level part of device and resource management is controlled by handlers, which are not libraries, but tasks, and communicate by passing messages. A task is an execution path through address space. In other words, a set of program instructions that is loaded in memory. ...

One important type of handler is a filesystem handler. The AmigaOS can make use of any filesystem for which a handler has been written, a possibility that has been exploited by programs like CrossDOS and by a few "alternative" file systems to the standard OFS and FFS. These file systems allow one to add new features like journaling or file privileges, which aren't found in the standard operating system. See Filing system for this term as it is used in libraries and offices In computing, a file system is a method for storing and organizing computer files and the data they contain to make it easy to find and access them. ... CrossDOs was invented in 1986 by Arthur Brooney to Address the needs of higher performance users. ... On the Amiga the Old File System was the filesystem for Amiga OS before the Amiga Fast File System. ... The Amiga Fast File System (FFS) is an advanced file system used on the Amiga personal computer. ... A journaling (or journalling) file system is a file system that logs changes to a journal (usually a circular log in a specially-allocated area) before actually writing them to the main file system. ... Most modern file systems have methods of administering permissions or access rights to specific users and groups of users. ...

Handlers typically expose a device name to the DOS, which can be used to access the peripheral (if any) associated with the handler. Disk Operating System (specifically) and disk operating system (generically), most often abbreviated as DOS (not to be confused with the DOS family of disk operating systems for the IBM PC compatible platform), refer to operating system software used in most computers that provides the abstraction and management of secondary storage...

As an example of these concepts, the SPEAK: handler can have text sent to it. The handler makes use of translator.library, which converts text into phonemes, then it writes the phonemes to narrator.device, which translates the phonemes into intoned speech samples and itself uses audio.device to play them through the Amiga's audio hardware. In human language, a phoneme is the theoretical representation of a sound. ...

Device names are case insensitive (uppercase by convention) strings followed by a colon. After the colon a specifier can be added, which gives the handler additional information about what is being accessed and how. In the case of filesystem, the specifier usually consists of a path to a file in the filesystem; for other handlers, specifiers usually set characteristics of the desired input/output channel (for the SER: serial port driver, for example, the specifier will contain bit rate, start and stop bits, etc). Text sometimes exhibits case sensitivity, that is, words can differ in meaning based on the differing use of uppercase and lowercase letters. ... This article is about colons in punctuation. ... A path is the general form of a file or directory name, giving a files name and its unique location in a file system. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... The asynchronous start-stop is the more common of two basic modes of teletypewriter operation, allowing a common means of encoding characters over a serial link such as RS-232. ...

Filesystems expose drive names as their device names. For example, DF0: by default refers to the first floppy drive in the system. On many systems DH0: is used to refer to the first hard drive.

Filesystems also expose volume names, following the same syntax as device names: these identify the specific medium in the file system-managed drive. If DF0: contains a disk named "Workbench", then Workbench: will be a volume name that can be used to access files in DF0:.

If one wanted to access a file named "Amp" located in directory "Win" of the disk with name "Work" in drive DF0:, one could write

 DF0:Win/Amp 

or

 Work:Win/Amp 

However, these are not completely equivalent, since when the latter form is used, the system knows that the wanted volume is "Work" and not just any volume in DF0:. Therefore, whenever a requested file on "Work" is being accessed without volume "Work" being present in any drive, it will say something to the effect of:

 Please insert volume Work in any drive 

Programs often need to access files without knowing their physical location (either the drive or the volume): they only know the "logical path" of the file, i.e. whether the file is a library, a documentation file, a translation of the program's messages, etc. A computer program is a collection of instructions that describe a task, or set of tasks, to be carried out by a computer. ...

This is solved in AmigaOS by the use of assigns. An assign follows, again, the same syntax as a device name; however, it already points to a directory inside the filesystem. The place an assign points to can be changed at any time by the user. Standard assigns that are generally present in an AmigaOS system include

• SYS:, which points to the boot drive's root directory; this is the only assign created automatically by the kickstart
• LIBS:, pointing to a directory containing the system's libraries, usually SYS:Libs/
• DEVS:, pointing to a directory containing the system's devices, usually SYS:Devs/
• C:, pointing to a directory containing shell commands, usually SYS:C/
• PROGDIR:, this is not normally accessible to a user but all programs have this assigned to them behind the scenes so that they do not need to know where they have been stored on disk.

AmigaOS influence on other operating systems

AmigaOS and clones

AmigaOS has spawned at least two "clone" operating systems over time. Image File history File links AmigaOS.svg‎ Vector version of en:Image:AmigaOS.png. ... Image File history File links AmigaOS.svg‎ Vector version of en:Image:AmigaOS.png. ...

• AROS, or AROS Research Operating System is an attempt to clone the AmigaOS API in a portable open-source operating system. Although not binary compatible with AmigaOS (unless running on 68k), users have reported it to be highly source code compatible.

• MorphOS is a PowerPC native operating system, originally created when the future of the Amiga looked uncertain. It provides binary compatibility with "OS-friendly" AmigaOS applications (that is, those applications which do not access any native, legacy Amiga hardware directly). A version which runs on Classic Amigas with PPC accelerator cards has been released.

• Although not strictly Amiga related, a fork of the FreeBSD 4.8 release, called DragonFly BSD, has been created by a former FreeBSD developer and Amiga programmer Matt Dillon. DragonFly BSD aims to make the FreeBSD kernel more like AmigaOS architecturally, featuring message-passing in the kernel and allowing for very efficient and virtually mutex-free SMP support.

• BeOS features also a centralized structure supporting Datatypes, which is a direct inheritance from the same Amiga original solution which allow the entire OS to recognize all kind of files (text, music, videos, documents, etc.) with standard file descriptors. Datatype system provides entire system and any productivity tools with standard loaders and savers for these files, without having the necessity to embed multiple file loading capabilities into any single program.

• AtheOS was inspired by AmigaOS, and originally intended to be a clone of AmigaOS. Syllable is a fork of AtheOS, and includes some AmigaOS and BeOS like qualities.

• The operating system of the 3DO Interactive Multiplayer bore a very strong resemblance to AmigaOS, and was developed by RJ Mical,^[4] the creator of the Amiga's Intuition user interface.^[5]

What is AROS? AROS (Amiga Research Operating System) is an open source implementation of the AmigaOS 3. ... MorphOS is a mixed proprietary and open source operating system produced for the Pegasos PowerPC (PPC)-processor-based computer, most models of PPC-accelerated classic Amiga computers, and the EFIKA PPC consumer device. ... FreeBSD is a Unix-like free operating system descended from AT&T UNIX via the Berkeley Software Distribution (BSD) branch through the 386BSD and 4. ... DragonFly BSD is a free Unix-like operating system created as a fork of FreeBSD 4. ... Matt Dillon is a computer scientist, born July 1, 1966 in the Bay Area and living in Berkeley, California. ... Mutual exclusion (often abbreviated to mutex) algorithms are used in concurrent programming to avoid the simultaneous use of un-shareable resources by pieces of computer code called critical sections. ... Symmetric multiprocessing, or SMP, is a multiprocessor computer architecture where two or more identical processors are connected to a single shared main memory. ... BeOS is an operating system for personal computers which began development by Be Inc. ... AtheOS was a free software operating system for x86-based computers. ... Syllable is a free and open source operating system for Intel x86 Pentium and compatible processors. ... BeOS is an operating system for personal computers which began development by Be Inc. ... For other uses, see 3DO. Crash n Burn on the 3DO, the systems first bundled title. ... RJ Mical created video games at Williams Electronics, helped invent the Amiga computer, co-invented the Atari Lynx and the 3DO Interactive Multiplayer with Dave Needle. ... Amiga Workbench (1985) The Amiga computer was launched by Commodore in 1985 with a GUI called Workbench based on an internal engine which drives all the input events called Intuition, and developed almost entirely by RJ Mical. ...

Easter eggs

Some versions of AmigaOS included copyright messages as Easter eggs that required some trickery to access. Not to be confused with copywriting. ... A virtual Easter egg is a hidden message or feature in an object such as a movie, book, CD, DVD, computer program, or video game. ...

• In version 1.x, by holding down both Shift keys and both Alt keys and pressing the function keys F1 through F10, you could see copyright messages in the title bar. As an example, pressing F10 resulted in the message "Moral support: Joe Pillow and the Dancing Fools". "Joe Pillow" was the name used to book a seat on a flight which was used to transport a prototype Amiga computer to a computer trade show ^[6].
• In versions 2.x and 3.0, the secret message was accessed by repeatedly selecting the "About..." option from the Workbench menu, and leaving the resulting dialog box open. When there were enough (approximately 20) dialog boxes open at the same time, the next one had a secret message instead of the normal one. In version 3.1 the secret message was openly integrated into the "About..." dialog box.
• The Amiga 1000 Kickstart floppy diskette master for AmigaDOS 1.0 was not erased prior to duplication, and contains the remnants of various source code and header text files on the disk.

The Alt key on a modern Windows keyboard The Alt key on an IBM PC keyboard is the key located immediately to either side of the Space bar, used to change (alternate) the function of other pressed keys. ... Example of dialog box from Microsoft Windows Dialog boxes are special windows which are used by computer programs or by the operating system to display information to the user, or to get a response if needed. ...

References

1. ^ http://uk.aminet.net/misc/antiq/ARP_13.readme
2. ^ ARP is referred to as the AmigaDOS Replacement Project in ARP version 1.1's arpbase.h, available from ftp://ftp.funet.fi/pub/amiga/ancient/ex-amiga-s/archive/
3. ^ From PC Magazine, October 22, 1996 Inside Track By John C. Dvorak
4. ^ Mical Page
5. ^ A history of the Amiga, part 3: The first prototype: Page 3
6. ^ Article about Joe Pillow on AmigaU http://www.amigau.com/aig/pillow.html

is the 295th day of the year (296th in leap years) in the Gregorian calendar. ... Year 1996 (MCMXCVI) was a leap year starting on Monday (link will display full 1996 Gregorian calendar). ...

See also

• AmigaOS versions
• AROS
• Comparison of operating systems

There have been many different versions of the AmigaOS operating system during its two decades of history. ... What is AROS? AROS (Amiga Research Operating System) is an open source implementation of the AmigaOS 3. ... These tables compare general and technical information for a number of widely used and currently available operating systems. ...

External links

• Official AmigaOS 4 homepage
• AmigaOS4 PreRelease Update 1 review
• AmigaOS4 PreRelease Update 4 first impressions
• AmigaOS Support homepage
• The Workbench Nostalgia Page – Very detailed information on all known versions of AmigaOS.
• Amiga History Guide
• AmigaScene.nl - Information about Workbench GUI concepts and other Amiga / AmigaOne related material (Dutch)
• Reference Library
• Development site dedicated to Amiga systems
• Amiga user community portal
• Amiga Developer Help Site
• AmigaOS4 Free Files Archive
• Aminet – Amiga OS all versions/MorphOS Free Files Archive
• Amiga.sf Compendium of OpenSource ported software for AmigaOS
• Amiga Disassemblies including a commented disassembly of the Amiga Exec multitasker