Clock Signal

Clock Signal launches classic software from disk, tape, or ROM images while automatically selecting and configuring the machine that should run them. It is designed for people who want to use 8- and 16-bit software without learning the controls, setup conventions, or loading commands of the original hardware, with latency kept as low as possible.

Its emulation roster covers the Acorn Electron, BBC Micro and Archimedes, Amstrad CPC, Apple II series, early Macintosh, Atari 2600 and ST, ColecoVision, Enterprise 64/128, Commodore VIC-20 and Amiga, MSX 1 and 2, Oric 1 and Atmos, early PC compatibles, Sega Master System, Sinclair ZX80/81 and ZX Spectrum, and Tandy CoCo and Thomson MO5/6. The currently identified emulations include the Apple II, Apple II Plus and IIe; Macintosh 128K, 512K, 512Ke and Plus; MSX 1 and 2; and Tandy CoCo 1 and 2.

A single-click load action accepts supported media, uses static and runtime analysis to determine the appropriate configuration, sends any commands needed to start the software, and accelerates loading where possible. Signal-processing techniques reproduce the original machines’ output closely, including limitations such as composite-only video on an emulated VIC-20, while macOS uses a native Cocoa and Metal implementation.

Files stay in their normal desktop or dock locations because Clock Signal does not import them or take ownership of them, making it suitable for directly launching personal retro-software collections. It is freeware for macOS on Intel and Apple Silicon, and the current version is dated 2026-07-23.