Dissecting Appleβs Sparse Image Format (ASIF)
ASIF takes a lot of inspiration from existing virtual disk formats. Practically, that means itβs another sparse virtual disk format, and functions very similar to sparse VMDK, VHDX or QCOW2 files (for the uninitiated, it allow you to store a large disk, or file, in a smaller, βsparseβ manner).
Shortly before the release of macOS Tahoe (late 2025), I thought itβd be a fun exercise to try and write a parser for ASIF files.
Previously: