{"id":620,"date":"2012-07-10T12:42:50","date_gmt":"2012-07-10T04:42:50","guid":{"rendered":"http:\/\/rmohan.com\/?p=620"},"modified":"2012-07-10T12:42:50","modified_gmt":"2012-07-10T04:42:50","slug":"linux-booting-process-sequence","status":"publish","type":"post","link":"https:\/\/mohan.sg\/?p=620","title":{"rendered":"Linux Booting Process Sequence"},"content":{"rendered":"<p><strong>Linux Booting Process Sequence<\/strong><\/p>\n<ol>\n<li><span style=\"font-family: verdana,sans-serif;\">When the computer is switched on, it automatically invokes BIOS [a ROM chip embedded in the motherboard].<\/span><\/li>\n<li><span style=\"font-family: verdana,sans-serif;\">The BIOS will start the processor and perform a POST [power on self test] to check whether the connected device are ready to use and are working properly.<\/span><\/li>\n<li><span style=\"font-family: verdana,sans-serif;\">Once the POST is completes BIOS will jump to a specified location in the RAM and check for the booting device. The boot sector is always the first sector of the hard disk and BIOS will load the MBR into the memory.<\/span><\/li>\n<li><span style=\"font-family: verdana,sans-serif;\">Here the boot loader takes the control of the booting process.<\/span><\/li>\n<li><span style=\"font-family: verdana,sans-serif;\">LILO or GRUB is the boot loaders commonly available. It will help the user to select various boot options.<\/span><\/li>\n<li><span style=\"font-family: verdana,sans-serif;\">Depending on the boot option selected the kernel is loaded.<\/span><\/li>\n<li><span style=\"font-family: verdana,sans-serif;\">After kernel is loaded the kernel will take the control of the booting process<\/span><\/li>\n<li><strong><span style=\"font-family: verdana,sans-serif;\">initrd<\/span><\/strong><span style=\"font-family: verdana,sans-serif;\"> will be loaded which contains drivers to detect hardware (Initialization of RAM Disk)<\/span><\/li>\n<li><span style=\"font-family: verdana,sans-serif;\">Then it will initialize all the hardware including I\/O processors etc.<\/span><\/li>\n<li><span style=\"font-family: verdana,sans-serif;\">Kernel then mounts the root partition as read-only<\/span><\/li>\n<li><span style=\"font-family: verdana,sans-serif;\">INIT is loaded.<\/span><\/li>\n<li><span style=\"font-family: verdana,sans-serif;\">INIT will mount the root partition and other partitions as read\/write and checks for file system errors.<\/span><\/li>\n<li><span style=\"font-family: verdana,sans-serif;\">Sets the System Clock, hostname etc..<\/span><\/li>\n<li><span style=\"font-family: verdana,sans-serif;\">Based on the Runlevel, it will load the services and runs the startup scripts (Network, cups, nfs, etc.)<\/span><\/li>\n<li><span style=\"font-family: verdana,sans-serif;\">Finally it runs the <\/span><strong><span style=\"font-family: verdana,sans-serif;\">rc.local<\/span><\/strong><span style=\"font-family: verdana,sans-serif;\"> script.<\/span><\/li>\n<li><span style=\"font-family: verdana,sans-serif;\">Now the login prompt will appear.<\/span><\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>Linux Booting Process Sequence<\/p>\n<p> When the computer is switched on, it automatically invokes BIOS [a ROM chip embedded in the motherboard]. The BIOS will start the processor and perform a POST [power on self test] to check whether the connected device are ready to use and are working properly. Once the POST is completes BIOS [&#8230;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[29],"tags":[],"_links":{"self":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/620"}],"collection":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=620"}],"version-history":[{"count":2,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/620\/revisions"}],"predecessor-version":[{"id":622,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/620\/revisions\/622"}],"wp:attachment":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=620"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=620"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=620"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}