Dissecting Apple's Sparse Image Format (ASIF)
Summary
Erik Schamper’s article offers a detailed reverse-engineering narrative of Apple’s ASIF sparse disk image format introduced with macOS Tahoe. It covers preparing test ASIF files, identifying header fields, and deriving the data layout (directories, tables, data entries, and bitmaps), then presents formulas to map disk offsets to ASIF chunks. The piece also highlights community-driven research (huven’s ASIF repository) and points to open-source tooling in dissect.hypervisor for parsing ASIF files.