AmigaOS versions

AmigaOS is the proprietary native operating system of the Amiga personal computer. Since its introduction with the launch of the Amiga 1000 in 1985, there have been four major versions and several minor revisions of the operating system.

Initially the Amiga operating system had no strong name and branding, as it was simply considered an integral part of the Amiga system as a whole. Early names used for the Amiga operating system included "CAOS" and "AmigaDOS". Another non-official name was "Workbench", from the name of the Amiga desktop environment, which was included on a floppy disk named "Amiga Workbench".

Version 3.1 of the Amiga operating system was the first version to be officially referred to as "Amiga OS" (with a space between "Amiga" and "OS") by Commodore, possibly inspired by Apple renaming the classic Mac operating system from "System" to "Mac OS".

Version 4.0 of the Amiga operating system was the first version to be branded as a less generic "AmigaOS" (without the space).

What many consider the first versions of AmigaOS (Workbench 1.0 up to 3.0) are here indicated with the Workbench name of their original disks.

Workbench 1.0 was released for the first time in October 1985. The 1.x series of Workbench defaults to a distinctive blue and orange color scheme, designed to give high contrast on even the worst of television screens (the colors can be changed by the user). Version 1.1 consists mostly of bug fixes and, like version 1.0, was distributed only for the Amiga 1000. The entire Workbench operating system consisted of three floppy disks: Kickstart, Workbench and ABasic by MetaComCo.

The Amiga 1000 needed a Kickstart disk to be inserted into floppy drive to boot up. An image of a simple illustration of a hand on a white screen, holding a blue Kickstart floppy, invited the user to perform this operation. After the kickstart was loaded into a special section of memory called the writable control store (WCS), the image of the hand appeared again, this time inviting the user to insert the Workbench disk.

Workbench version 1.2 was the first to support Kickstart stored in a ROM. A Kickstart disk was still necessary for Amiga 1000 models; it was no longer necessary for Amiga 500 or 2000, but the users of these systems had to change the ROMs (which were socketed) to change the Kickstart version.

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