Hollow 0.1.1

Hollow 0.1.1

Fixes:

• Hollow could crash when the map changed while the pointer was over it: after zooming with ⌘↑ or ⌘↓, going back and forward, or after files changed on disk. It no longer does.
• The outline around the item under the pointer blinked about once a second while scanning a busy folder such as your home folder. It now stays put.

To open the app the first time, see the 0.1.0 notes.

Made with love by Dmitry Tretyakov

Hollow 0.1.0

Hollow 0.1.0

Hollow is a native macOS app that shows where your disk space went. It scans a folder or a whole disk and draws every file as a shaded rectangle, sized by the space it takes on disk. It runs on Apple silicon Macs with macOS 14 or later. A hollow command-line tool uses the same scanner.

Speed

Timings are warm-cache medians on a MacBook Air with an Apple M5 (10 cores), from docs/bench.md.

• Home folder with 1,504,012 files: Hollow took 5.19 s. A model of GrandPerspective's scanner took 30.24 s, so Hollow was 5.8× faster.
• Against the GrandPerspective 3.8.1 app itself, timed from its own log: 1.67 s against 6.69 s on /Applications (4.0×), and 1.56 s against 8.99 s on /System/Library (5.8×).
• Whole data volume (2,373,255 files): 9.43 s.

Opening the app

The app is ad-hoc signed and not notarized, so macOS blocks the first launch. Unzip Hollow.zip, move Hollow.app to Applications, right-click it, choose Open, and confirm Open in the dialog. You only do this once. On newer macOS versions you may need to allow it under System Settings › Privacy & Security ("Open Anyway").

Known limitations

• Benchmarks are warm-cache numbers from one machine. Cold-cache times depend on your SSD.
• The GrandPerspective comparison uses a Swift model of its scanner, plus one run of the real app on two folders.
• On one thread Hollow is slower than a plain fts walk on some folders (19.61 s against 18.39 s on the home folder). The speedup comes from reading folders in parallel.
• Without Full Disk Access some folders can't be read, so totals come up short. Those folders are marked on the map.
• APFS clones are counted at full size, so a folder full of clones can add up to more than the space it really uses.
• Apple silicon and macOS 14 or later only. No Intel build, no App Store version.

Made with love by Dmitry Tretyakov