{"id":422,"date":"2020-08-18T19:23:47","date_gmt":"2020-08-18T20:23:47","guid":{"rendered":"http:\/\/www.linux-tutorial.info\/?page_id=77"},"modified":"2020-08-22T19:26:39","modified_gmt":"2020-08-22T20:26:39","slug":"this-is-the-page-title-toplevel-255","status":"publish","type":"page","link":"http:\/\/www.linux-tutorial.info\/?page_id=422","title":{"rendered":"The EXT2 Superblock"},"content":{"rendered":"\n<title>The EXT2 Superblock<\/title>\n<p>\nThe Superblock contains a description of the basic size and shape of this file system.\nThe information within it allows the file system manager to use and maintain the file system.\nUsually only the Superblock in Block Group 0 is read when the file system is mounted\nbut each Block Group contains  a duplicate copy in case of file system corruption.\nAmongst other information it holds the:\n<p>\n<dl compact>\t<dt><b>Magic Number<\/b><\/dt><dd> This allows the mounting software to check that this is\n\tindeed the Superblock for an EXT2 file system.  For the current version of\n\t\t<tt>EXT2<\/tt> this is <em>0xEF53<\/em>.\n\t<dt><b>Revision Level<\/b><\/dt><dd> The major and minor revision levels allow the mounting\n\t\tcode to determine whether or not this file system supports features\n\t\tthat are only available in particular revisions of the file system.\n\t\tThere are also feature compatibility fields which help the mounting code\n\t\tto determine which new features can safely be used on this file system,\n\t<dt><b>Mount Count and Maximum Mount Count<\/b><\/dt><dd> Together these allow the system to\n\t\tdetermine if the file system should be fully checked.  The mount count\n\t\tis incremented each time the file system is mounted and when it equals\n\t\tthe maximum mount count the warning message &#8220;maximal mount count reached,\n\t\trunning e2fsck is recommended&#8221; is displayed,\n\t<dt><b>Block Group Number<\/b><\/dt><dd> The Block Group number that holds this copy of\n\t\tthe Superblock,\n\t<dt><b>Block Size<\/b><\/dt><dd> The size of the block for this file system in bytes, for\n\t\texample 1024 bytes,\n\t<dt><b>Blocks per Group<\/b><\/dt><dd> The number of blocks in a group.  Like the block size\n\t\tthis is fixed when the file system is created,\n\t<dt><b>Free Blocks<\/b><\/dt><dd> The number of free blocks in the file system,\n\t<dt><b>Free Inodes<\/b><\/dt><dd> The number of free Inodes in the file system,\n\t<dt><b>First Inode<\/b><\/dt><dd> This is the inode number of the first inode in the file system.\n\t\tThe first inode in an EXT2 root file system would be the directory entry\n\t\tfor the &#8216;\/&#8217; directory.\n<\/dl>\n<p>\n","protected":false},"excerpt":{"rendered":"<p>The EXT2 Superblock The Superblock contains a description of the basic size and shape of this file system. The information within it allows the file system manager to use and maintain the file system. Usually only the Superblock in Block &hellip; <a href=\"http:\/\/www.linux-tutorial.info\/?page_id=422\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-422","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages\/422","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=422"}],"version-history":[{"count":1,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages\/422\/revisions"}],"predecessor-version":[{"id":745,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages\/422\/revisions\/745"}],"wp:attachment":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=422"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}