MagiC ROM Builder

Turn Andreas Kromke's MagiC for Atari into a 256 KB ROM image that boots in place of TOS, plus the boot floppy or hard disk files it loads its desktop from. The ROM runs at $E00000: in the SidecarTridge TOS Emulator on an STE or Mega STE, on an ST or Mega ST with the SidecarTridge 256 KB Decoder, or in Hatari. Everything is built in your browser.

What is MagiC?

MagiC is an alternative operating system for the Atari ST family, written by Andreas Kromke. It started in 1990 as Mag!X and replaces TOS with a multitasking system: several GEM programs run at the same time, each in its own windows, while it stays compatible with the software written for TOS.

  • Multitasking AES with a modern window manager, and the MAGXDESK desktop.
  • MVDI, the fast graphics library by Sven and Wilfried Behne, with loadable screen drivers.
  • Long file names (VFAT), shared libraries, the MCMD command line and a set of small tools.

It was sold commercially for Atari computers, and later as MagiC Mac and MagiC PC for other machines. In 2018 Kromke published the complete sources under the GPLv3, and in 2026 he released MagiC 6.30 for Atari computers: the version this page builds.

Why a ROM?

MagiC normally ships as a program: TOS boots first, then AUTO\MAGXBOOT loads the kernel (MAGIC.RAM) from disk into RAM and hands the machine over. In ROM, MagiC is the operating system from the moment you switch on:

  • No TOS needed, and no loader in the AUTO folder.
  • About 240 KB more free RAM: the kernel runs in place from ROM instead of being copied into memory. On a 1 MB ST that is almost a quarter of the machine.
  • Faster boot: the kernel is not read from floppy or hard disk on every start.
  • One click to switch: with the SidecarTridge TOS Emulator, choose the MagiC image or a TOS image from the same device.

The ROM still loads its screen drivers and desktop from a disk, so this page also builds the boot floppy or the hard disk files that go with it.

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