{"id":52471,"date":"2026-06-30T15:48:57","date_gmt":"2026-06-30T19:48:57","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=52471"},"modified":"2026-06-30T15:52:34","modified_gmt":"2026-06-30T19:52:34","slug":"dissecting-apples-sparse-image-format-asif","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2026\/06\/30\/dissecting-apples-sparse-image-format-asif\/","title":{"rendered":"Dissecting Apple&rsquo;s Sparse Image Format (ASIF)"},"content":{"rendered":"<p><a href=\"https:\/\/schamper.dev\/dissecting-apples-sparse-image-format-asif\/\">Erik Schamper<\/a>:<\/p>\n<blockquote cite=\"https:\/\/schamper.dev\/dissecting-apples-sparse-image-format-asif\/\">\n<p>ASIF takes a lot of inspiration from existing virtual disk formats. Practically, that means it&rsquo;s 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, &ldquo;sparse&rdquo; manner).<\/p>\n<p>Shortly before the release of macOS Tahoe (late 2025), I thought it&rsquo;d be a fun exercise to try and write a parser for ASIF files.<\/p>\n<\/blockquote>\n\n<p>Previously:<\/p>\n<ul>\n<li><a href=\"https:\/\/mjtsai.com\/blog\/2025\/09\/17\/dropdmg-3-7\/\">DropDMG 3.7<\/a><\/li>\n<li><a href=\"https:\/\/mjtsai.com\/blog\/2025\/06\/23\/asif-disk-images-in-macos-tahoe\/\">ASIF Disk Images in macOS Tahoe<\/a><\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"<p>Erik Schamper: ASIF takes a lot of inspiration from existing virtual disk formats. Practically, that means it&rsquo;s 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, &ldquo;sparse&rdquo; manner). Shortly before the release [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"apple_news_api_created_at":"2026-06-30T19:49:00Z","apple_news_api_id":"fa5824a2-2ab1-42bd-aef6-7dec7845112b","apple_news_api_modified_at":"2026-06-30T19:52:36Z","apple_news_api_revision":"AAAAAAAAAAAAAAAAAAAAAA==","apple_news_api_share_url":"https:\/\/apple.news\/A-lgkoiqxQr2u9n3seEURKw","apple_news_coverimage":0,"apple_news_coverimage_caption":"","apple_news_is_hidden":false,"apple_news_is_paid":false,"apple_news_is_preview":false,"apple_news_is_sponsored":false,"apple_news_maturity_rating":"","apple_news_metadata":"\"\"","apple_news_pullquote":"","apple_news_pullquote_position":"","apple_news_slug":"","apple_news_sections":"\"\"","apple_news_suppress_video_url":false,"apple_news_use_image_component":false,"footnotes":""},"categories":[4],"tags":[1396,30,2742,270,71,232,2251],"class_list":["post-52471","post","type-post","status-publish","format-standard","hentry","category-programming-category","tag-disk-image","tag-mac","tag-macos-tahoe-26","tag-parser","tag-programming","tag-python","tag-virtualization"],"apple_news_notices":[],"_links":{"self":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/52471","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/comments?post=52471"}],"version-history":[{"count":2,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/52471\/revisions"}],"predecessor-version":[{"id":52476,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/52471\/revisions\/52476"}],"wp:attachment":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/media?parent=52471"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/categories?post=52471"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/tags?post=52471"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}