davepl/blinkendisk

BlinkenDisk is a small macOS app that sits in your menu bar and lights up a tiny LED indicator whenever one of your internal drives is actively reading or writing data. The idea comes from the blinking drive activity lights that used to appear on the front panels of old desktop computers. This app brings that same quick visual feedback to modern Macs. Each drive you choose to monitor gets its own LED in the menu bar. When the app detects I/O activity, the LED turns on briefly, then fades back to a dim state so you can always see where it sits. During sustained heavy activity, such as a long file copy or backup, the LED stays solidly lit rather than flickering. The app checks drive statistics every 50 milliseconds using macOS system-level APIs, which cover entire disk devices rather than individual partitions. A settings window lets you configure which drives to watch, what color to use for each LED (red, green, yellow, amber, or blue), the order they appear in the menu bar, and how long each flash lasts. The default flash duration is 10 milliseconds, which is short enough to register individual I/O bursts. Your choices are saved and restored the next time you launch the app. Clicking any LED in the menu bar opens a small menu with shortcuts to Settings and Quit. The app is built with Swift and targets macOS 12 (Monterey) or newer. Building it requires only the Xcode command-line tools, not the full Xcode IDE. A provided build script handles compiling and packaging the final app bundle. The app runs without a Dock icon or a floating window, it lives entirely within the macOS menu bar. The license allows personal and non-commercial use. Organizations and commercial users need written permission from the author before deploying or redistributing the app. The repository also notes current limitations: it monitors whole disks rather than individual volumes, does not separate read and write activity into distinct indicators, and does not cover network-attached drives.