{"id":421,"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-254","status":"publish","type":"page","link":"http:\/\/www.linux-tutorial.info\/?page_id=421","title":{"rendered":"The EXT2 Inode"},"content":{"rendered":"\n<title>The EXT2 Inode<\/title>\n<p>\n<img decoding=\"async\" src=\"ext2_inode.gif\">\n<p>\nFigure 9.2: EXT2 Inode\n<p>\n<p>In the <tt>EXT2<\/tt> file system, the inode is the basic building block; every\nfile and directory in the file system is described by one and only one inode.\nThe EXT2 inodes for each Block Group are kept in the inode table together\nwith a bitmap that allows the system to keep track of allocated and unallocated\ninodes. The figure above shows the format of an EXT2 inode,\namongst other information, it contains the following fields:\n<p>\n<dl compact>\t<dt><b>mode<\/b><\/dt><dd> This holds two pieces of information; what\n\t\tthis inode describes and the permissions that users have\n\t\tto it.\n\t\tFor EXT2, an inode can describe one\n\t\tof file, directory, symbolic link, block device, character device or\n\t\tFIFO.\n\t<dt><b>Owner Information<\/b><\/dt><dd> The user and group identifiers of the owners of this\n\t\tfile or directory.  This allows the file system to correctly allow\n\t\tthe right sort of accesses,\n\t<dt><b>Size<\/b><\/dt><dd> The size of the file in bytes,\n\t<dt><b>Timestamps<\/b><\/dt><dd> The time that the inode was created and the last time that\n\t\tit was modified,\n\t<dt><b>Datablocks<\/b><\/dt><dd> Pointers to the blocks that contain the data that this\n\t\tinode is describing.  The first twelve are pointers to the\n\t\tphysical blocks containing the data described by this inode and the\n\t\tlast three pointers contain more and more levels of indirection.\n\t\tFor example, the double indirect blocks pointer points at a block of\n\t\tpointers to blocks of pointers to data blocks.\n\t\tThis means that files less than or equal to twelve data blocks in length\n\t\tare more quickly accessed than larger files.\n<\/dl>\n<p>\nYou should note that EXT2 inodes can describe special device files.  These are\nnot real files but handles that programs can use to access devices.  All of the\ndevice files in <tt>\/dev<\/tt> are there to allow programs to access Linux&#8217;s devices.\nFor example the <font face=\"helvetica\">mount<\/font> program takes as an argument the device file that it wishes to\nmount.\n","protected":false},"excerpt":{"rendered":"<p>The EXT2 Inode Figure 9.2: EXT2 Inode In the EXT2 file system, the inode is the basic building block; every file and directory in the file system is described by one and only one inode. The EXT2 inodes for each &hellip; <a href=\"http:\/\/www.linux-tutorial.info\/?page_id=421\">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-421","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages\/421","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=421"}],"version-history":[{"count":1,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages\/421\/revisions"}],"predecessor-version":[{"id":744,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages\/421\/revisions\/744"}],"wp:attachment":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=421"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}