Manual USB boot and fundamentals for Linux

Basic Minimalist catalog file diagram after successful production

First, the basic system guidance process:

First, the system to boot the Isolinux.bin executable, this program is used for booting on the mobile media, Isolinux.bin run successfully will load its configuration file syslinux.cfg, which defines the Vmlinuz and Initrd.img call methods. Vmlinuz is a compressed version of Vmlinux, both of which are Linux kernels. Isolinux.bin is passed to Vmlinuz as the Linux kernel and loads the kernel according to the INITRD.IMG parameters defined in its configuration, and the Linux kernel calls initrd.img based on the initrd.img invocation parameters obtained. The basic function of initrd.img is the root path mount, which has the meaning of eliminating the recompilation of the Vmlinuz kernel under different root path hardware. Initrd.img the system startup program based on the call parameters to the parameter path (the ISO installation image is used here), the system starts up.

Second, the basic production process of the guide disk:

The first step: Extract the files needed to make the boot image in the Isolinux directory of the Linux installation disk, which is a micro Linux system.

Step Two: Edit the original file isolinux.cfg of the Isolinux.bin execution profile syslinux.cfg.

Default Vesamenu.c32timeout 600

The default defined here is VESAMENU.C32C, which is the function of the vesamenu.32c to start the menu appearance drawing extension tool. The timeout defined below refers to the user's choice of time limit.

Label Linux Menu label ^install CentOS 7 kernel vmlinuz append initrd=initrd.img inst.stage2=hd:label=centos Quietlabel Check Menu label Test this ^media & install CentOS 7 menu default kernel vmlinuz append initrd=initrd.img inst.st Age2=hd:label=centos Rd.live.check Quietmenu Separator # Insert an empty line# utilities Submenumenu begin ^troubleshootin G Menu Title Troubleshootinglabel Vesa Menu Indent count 5 menu label Install CentOS 7 in ^basic graphics mode text He  Lptry This option, if you ' re has trouble Installingcentos 7. Endtext kernel vmlinuz append initrd=initrd.img inst.stage2=hd:label=centos xdriver=vesa nomodeset Quietlabel Rescue Me  Nu Indent count 5 menu label ^rescue a CentOS system text HELPIF The system won't boot, this lets you access Filesand  Edit config files to try to get it booting again. Endtext kernel vmlinuz Append initrd=initrd.img inst.stage2=hd:label=centos rescue quietlabel memtest menu LABEL Run A ^memory Test Text HelpifYour system is has issues, a problem with Yoursystem's memory may be the cause.  Use this utility Tosee if the memory is working correctly. Endtext kernel Memtestmenu Separator # Insert an empty Linelabel local menu label Boot from ^local Drive Localboot 0xFF  Ffmenu Separator # Insert an empty linemenu separator # Insert a empty Linelabel returntomain menu label Return to ^main Menu Menu Exitmenu End

These are the specific definitions of each menu, which defines how each menu calls Vmlinuz and initrd.img.

Label Linux  menu label ^install CentOS 7  kernel vmlinuz  append initrd=initrd.img inst.stage2=hd:label= CENTOS quiet

Label is a label, similar to the title of grub. The kernel item represents the kernel to be loaded, and append is the suffix parameter, which is equivalent to the effect of a good-looking line break. Initrd=initrd.img is the initrd.img that defines the kernel, the Inst.stage2=hd:label=centos quiet is the root path that is loaded, Inst.stage2 is the file that loads the ISO, HD : Label=centos refers to the root path in a storage device labeled CentOS, which is a USB flash drive, so the name of the boot image and the USB flash drive must be centos.

If you do not want to display the menu mode, directly load the installation files, you can save vesamenu.32c to the default vesamenu.32c the beginning of Linux, which is loaded with the label Linux definition.

Step three: Make the boot image file Centos.iso

Modify the image file name to match the root path label in Syslinux.cfg. Set the Isolinux.bin as the boot file, tick the Generate Boot information table, which is the Ldlinux.sys boot information file in the last directory.

Fourth step: Save the image and write to the drive by booting-"write to the hard disk image." At this time uitral so will automatically syslinux.cfg file box Ldlinux.sys file generated on the U disk, and other files will be copied to the USB stick, when the U disk Isolinux.cfg can be deleted, and finally the image of the installation system to copy to the root directory.

Note: The files that are not covered in the USB flash drive are the Linux detection tools that are called in the background or other installation options.