The GRUB command uses a detailed

Command index: Background sets the background color in graphical mode. Blocklist The block manifest token of the output file. Boot boot the loaded operating system or sector chain loader. BOOTP uses BOOTP to initial network devices. Cat Displays the contents of the specified file. Chainloader load Sector chain loader. Clear clear the screen. CMP compares two files and reports different information between the two. Color changes the colors of the menu. ConfigFile loads the specified file as a configuration file. Debug turns on/off debugging mode. Default Sets the NUM item menu to the default value. Device declares the actual physical device that corresponds to the BIOS drive. DHCP uses DHCP to initialize network devices. DISPLAYAPM displays information about the APM BIOS. Displaymem shows the memory distribution of the current system as determined by GRUB, including all areas of physical memory. Dump displays the contents of many files. Embed if the device is a drive, the stage 1.5 is embedded behind the main boot sector. Fallback if an error occurs when the current menu item is called, Retry to find the file name on all partitions and display the device containing the file, after moving to NUM entry. If the parameter--set-root is set, it stops immediately after the first match is found, and the device is set to root. fontfile Specifies the Chinese font file and switches to Simplified Chinese display mode. foreground sets the foreground color in graphical mode. Fstest Switch the test mode of the file system. Geometry information about the output driver. Gfxmenu uses the Graphics menu in FILE. Halt shut down the system. Help displays helpful information for internal commands. Hiddenmenu hidden menu. Hide hides the specified partition by placing a hidden flag on the partition type. IFCONFIG Specifies the IP address, subnet mask, gateway, and server address. When no parameters are present, the current network configuration is displayed. The Impsprobe detects CPUs in accordance with the Intel multi-processor specification 1.1/1.4 through a number of cyclic operations in order to achieve better performance. INITRD loads the initialized virtual disk in the Linux format and sets the necessary parameters. Install STAGE1 to the specified device, install load STAGE2 required block list to STAGE2. Ioprobe detects the I/O port number of the specified device. Kernel attempts to load the master boot image file. Lock asIf the user is not authenticated, the execution of the command is terminated. Makeactive the root device as the active partition. Map maps the device. Md5crypt generates a password in a MD5 format. Module to the multi-boot image, load the boot module file (do not process the contents of the file, the user must determine the core requirements themselves). Modulenounzip is similar to ' module ' but is automatically disabled for understanding compression. Pager Switch Page mode when there are no parameters. Partnew Create a new primary partition. PartType changes the partition type of the specified partition (part). Password set the password. Pause terminates the run of the command and gives a piece of information. After any key is pressed, it will continue. Portmap for port mapping. Quit quit from the GRUB command line. RARP initializes the network device with Rarp. Read reads a 32-bit value from the specified location in memory and displays it in 16 binary form. Reboot restart the system. Root to set up the roots partition. Rootnoverify is similar to the ' root ' directive, but does not test the installation of the partition. This is for some systems that are installed outside of the disk area that GRUB can access, but still need to set the correct root partition. Some parameters that require a partition to be installed may be problematic. Run runs a boot file (non-impersonated) that is designed to boot the disc savedefault the current item to the default boot entry. Scdrom look for the system's first CD-ROM drive, and then assign it a drive letter for later use (--install). Or, start the system with a bootable disc in the drive. (--boot). Serial Initializes a serial device. Setkey Change the keyboard mapping relationship. Setup installs grub automatically. Splashimage graphics mode downloaded into the background image file. Terminal Select a terminal. TERMINFO Specifies the function of the terminal. TestLoad reads the entire contents of the file (specified by file) in a number of different ways, and compares it to test the file system's code. TESTVBE the VBE mode specified by the test (mode). TFTPSERVER Specifies the IP address of the TFTP server. Timeout sets the number of seconds to wait before starting the default menu automatically. Title Name menu item. Unhide removes the hidden flag from the specified partition (PARTITION) by clearing the hidden flags. Uppermem mandatory specifies only (Kbytes) KBThe upper memory. The Vbeprobe detects VBE information. Blocklist Usage: Blocklist File Description: The block manifest token for the output file. Boot usage: Boot description: Boot the loaded operating system or sector chain loader. BOOTP usage: BOOTP [--with-configfile] Description: Use BOOTP to initial network device. If the '--with-configfile ' parameter is used, this command will attempt to load a specific configuration file. Cat usage: Cat file Description: Displays the contents of the specified file. Chainloader usage: chainloader [--force] FILE Description: Load sector chain loader. If the--force parameter is used, the validity of the start identity of the sector is ignored. CMP usage: CMP FILE1 FILE2 Description: Compares two files and reports different information between the two. Color usage: color NORMAL [HIGHLIGHT] Description: Change the colors of the menu. Normal is used to specify the color when the menu item is unchecked, and HIGHLIGHT is used to specify the color of the menu item when it is selected. If you do not specify a HIGHLIGHT color, then we will use the inverse color value of NORMAL. The format of the color value is "FG/BG". FG and BG are the names of colors as follows: Black (black), Blue (blue), green (green), cyan (cyan), red (red), magenta (pink), Brown (Brown), Light-gray (bright Gray), Dark-gray (dark gray), Ligh T-blue (light blue), Light-green (light green), Light-cyan (pale Turquoise), light-red (Minghong), Light-magenta (light red), yellow (yellow) and white (Bai). Note that the value of BG can only be the first eight. In addition, if you want to use a blinking foreground color, you can use the prefix "blink-" before FG. ConfigFile Usage: ConfigFile file Description: Loads the specified files as a configuration file. Debug Usage: Debug Description: Turn on/off debugging mode. Default usage: default [num | ' saved '] Description: Sets the NUM item menu to the default value. Device usage: Device drive Device Description: Declares the BIOS drive corresponding to theActual physical device. This command is only used for the Grub command line. Portmap usage: Portmap prog_number vers_number Description: Port mapping. DHCP Usage: DHCP Description: Initial network device through DHCP. Splashimage Usage: Splashimage file Description: Graphics mode download into background image files. Foreground usage: Foreground RRGGBB Description: Sets the foreground color in graphical mode. RR stands for red, GG for Green, BB for blue. Note that they all use hexadecimal values. Background usage: Background RRGGBB Description: Sets the background color in graphical mode. RR stands for red, GG for Green, BB for blue. Note that they all use hexadecimal values. Clear usage: Clear Description: Clear the screen. DISPLAYAPM Usage: DISPLAYAPM Description: Displays information about the APM BIOS. Displaymem Usage: Displaymem Description: Displays the memory distribution of the current system as determined by GRUB, including all areas of physical memory. Dump usage: Dump from to Description: Displays the contents of many files. Note that the from is specified must be a GRUB file, to the specified must be an OS file. Embed usage: Embed stage1_5 device Description: If the device is a drive, the stage 1.5 is embedded behind the main boot sector. If it is a FFS partition, it can be embedded in the device's Hungry ' boot code ' area. and outputs the number of sectors that the Stage 1.5 occupies. Fallback usage: Fallback NUM Description: If an error occurs when invoking the current menu item, the Find usage is retried after moving to NUM entries: Find [--set-root] filename Description: Finds the file name on all partitions and displays the Equipment. If the parameter--set-root is set, it stops immediately after the first match is found, and the device is set to root. Fstest Usage: Fstest Description: Toggles the test mode of the file system. Gfxmenu Usage: Gfxmenu file Description: Use the Graphics menu in file. Geometry usage: Geometry drive [CYLINDER HEAD SECTOR [Total_sector]]Description: Information about the output drive. In the Grub shell program, you can set the drive parameter to any value using this command. If you omit the total number of sectors, the value is determined by default for other parameters. Halt usage: Halt [--NO-APM] Description: Shut down the system. If the APM (Advanced Power Management) feature is present, the system will be shut down using the APM BIOS unless the '--no-apm ' option is specified. Help usage: helper [--all] [PATTERN ...] Description: Displays the assistance information for the internal command. To see Help for all commands, use the '--all ' parameter. Hiddenmenu Usage: Hiddenmenu Description: Hide menu. Hide usage: Hide PARTITION Description: Hides the specified partition by placing a hidden flag on the partition type. Ifconfig usage: ifconfig [--ADDRESS=IP] [--GATEWAY=IP] [--mask=mask] [--server=ip] Description: Specify the IP address, subnet mask, gateway, and server address. When no parameters are present, the current network configuration is displayed. Impsprobe Usage: Impsprobe Description: The CPUs of the Intel Multi-processor specification 1.1/1.4 is detected through a number of cyclic operations in order to achieve better performance. INITRD usage: initrd FILE [ARG ...] Description: Loads the initialized virtual disk in the Linux format and sets the necessary parameters. Install usage: install [--stage2=stage2_file] [--force-lba] STAGE1 [d] DEVICE STAGE2 [ADDR] [P] [config_file] [Real_config_fi LE] Description: Install STAGE1 on the specified device, install load STAGE2 required block list to STAGE2. If you use the option ' d ', STAGE1 always tries to use the drive that installs STAGE2 instead of the boot disk. The STAGE2 is loaded at the specified address, and is automatically detected if no address is declared. If the option ' P ' is used or the configuration file is given, the first block of STAGE2 is modified to fix the configuration file location used when the actual Stage2 is started. For stage 1.5, the value is the path to stage 2. If stage 1.5 is installed and the actual configuration file is specified, the profile path is written to Stage2. Ioprobe usage: Ioprobe Drive Description: Detects the I/O port number of the specified device. Kernel usage: kernel [--no-mem-option] [--type=type] file [ARG ...] Description: Attempt to load the master boot image file. Other items are passed to the kernel as command-line arguments to the kernel. Before using this command, the module used by the kernel should be re-loaded. The parameter--type is used to describe the type of kernel, including "NetBSD", "FreeBSD", "OpenBSD", "Linux", "Biglinux" and "multiboot". The parameter--no-mem-option is used to describe memory parameters that do not have to be automatically passed Linux. Lock Usage: Lock Description: If the user is not authenticated, the execution of the command is terminated. Makeactive Usage: makeactive Description: Resets the root device to the active partition. Of course, this command is valid only for the primary partition of the PC's hard disk. Map usage: map [--status] [--hook] [--unhook] [--rehook] [[--read-only] [--fake-write] [--unsafe-boot] [--disable-chs-mode] [--disable-lba-mode] [--heads-per-cylinder=h] [--sectors-per-track=s] To_drive from_drive] Description: Mapping the device. This is useful for sector-chained booting, such as DOS. Here, the destination drive (to_drive) can be a disk file that uses the disk virtual function. Note that this requires that the disk files be stored continuously in the partition. In addition, if the--read-only parameter is used, the feature will cause ' disk ' to be read-only, and if the--fake-write parameter is used, the function will leave the ' disk ' in a false write, which can "write" the data, but it is not recorded on the real disk; If the--unsafe-boot parameter is used, the function will enable the ' disk ' to be real writable; If the--disable-chs-mode parameter is used, the CHS access function will be disabled; If the--disable-lba-mode parameter is used, the LBA access function will be disabled; H and S Specify the physical parameters of the virtual disk. If you use--status,--hook,--unhook,--One of the Rehook parameters, then the other commandsThe row parameters are ignored. Md5crypt Usage: Md5crypt Description: Generates a password in MD5 format. Module usage: module file [ARG ...] Description: For multiple boot images, load the boot module file (without processing the contents of the file, the user must determine the core requirements themselves). The remaining parameters are passed as the ' modulo fast command line ', like the ' kernel ' command. Modulenounzip usage: modulenounzip FILE [ARG ...] Description: Similar to ' module ', but automatically disables understanding compression. Pager usage: Pager [FLAG] Description: Toggles the page mode when there are no arguments. If the FLAG parameter is used, it is turned on when ' on ' and is off when it is ' off '. Partnew usage: partnew part TYPE START LEN Description: Create a new primary partition. Start is the starting sector area code, and LEN is the number of sectors it contains, and type is its partition. PartType usage: PartType Part type description: Changes the partition type (type) of the specified partition (part). Password usage: password [--md5] PASSWD [FILE] Description: Set the password. When it is at the top of the menu file, all interactive menu editing functions are disabled, including the Edit menu item (' e ')/enter command line (' C '). When the password is entered correctly (specified by passwd), the new menu file (specified by file) is loaded. If you do not specify a FILE entry, then the Disabled feature will be enabled. Of course, you can also use this command in a menu item to improve system security. The parameter--md5 description password (PASSWD) is encrypted using Md5crypt. Pause usage: Pause [MESSAGE ...] Description: Terminates the run of the command and gives a piece of information. After any key is pressed, it will continue. Quit Usage: Quit Description: Exits from the GRUB command line. Rarp Usage: Rarp Description: Initializes the network device with Rarp. Read usage: Read ADDR Description: Reads a 32-bit value from the specified location in memory and displays it in 16 binary form. Reboot usage: Reboot Description: Restart the system. Fontfile Usage: Fontfile file Description: Specify Chinese font files and switch to Simplified Chinese display mode. Scdrom Usage: scdrom [--install], [--BOOTCD] Description: Look for the first CD-ROM drive of the system and assign it a drive letter for subsequent use (--install). Or, start the system with a bootable disc in the drive. (--boot). Run Usage: Run File Description: Runs a bootstrap (non-impersonated) root usage that is designed for CD booting: root [DEVICE [Hdbias]] Description: Set the root partition. Set the root partition to the specified device, and then try to mount the partition to get the partition size (for passing in Es:esi, which is required for sector-chained startup). The BSD drive type is used to start the BSD core boot), and determine the PC partition where the BSD sub-partition resides. The optional disk offset parameter for the BSD core determines how many controllers are in front of the current controller. For example, if you have both an IDE and a SCSI disk, and the BSD root partition is on a SCSI disk, the disk offset is 1. Rootnoverify usage: rootnoverify [DEVICE [Hdbias]] Description: Similar to the ' root ' directive, but does not test the installation of the partition. This is for some systems that are installed outside of the disk area that GRUB can access, but still need to set the correct root partition. Some parameters that require a partition to be installed may be problematic. Savedefault Usage: Savedefault Description: Sets the current item as the default boot entry. Serial usage: serial [--unit=unit] [--port=port] [--speed=speed] [--word=word] [--parity=parity] [--stop=stop] [--device= DEV] Description: Initializes a serial device. The unit is used to specify the serial device to be used (e.g., 0 = = COM1); Port is used to specify the port number; Speed is used to specify the rate of communication; WORD is of length; PARITY is the value of the odd-even type (take ' no ', ' odd ' and ' even '). ); Stop is the length value of the stop bit; Option--device is used only in command-line mode to specify the file name of the TTY device. The default value is this, COM1, 9600, 8N1. Setkey usage: setkey [to_key From_key] Description: Change the keyboard mapping relationship. Map the From_key to To_key. The key here must beLetters, numbers, and the following special keys: Escape (Escape), Exclam (!), at (@), numbersign (#), Dollar ($), parenright ()), caret (^), ampersand (&), aster ISK (*), plus (+), percent (%), minus (-), underscore (_), equal (=), parenleft[(], BACKSPACE (BACKSPACE), tab (tab), Bracketleft ([), Braceleft ({), bracketright (]), Braceright (}), enter (carriage return), Control (control), semicolon (;), colon (:), quote ('), Doublequote (") , slash (/), Backquote ('), tilde (~), Shift (gearshift), backslash (/), Bar (|), comma (,), Less (<), period (.), Greater (>), ques tion (?), Alt (interactive), Space (space), CapsLock (uppercase), Fx (function key), and delete (delete). Setup usage: Setup [--prefix=dir] [--stage2=stage2_file] [--force-lba] install_device [image_device] Description: Install grub automatically. This command installs grub on the specified device using the more flexible install command. If an image device is given, grub is found on the device, otherwise the default root device is used. The root device can be specified with the root command. If you confirm that the system BIOS should support LBA mode, but GRUB does not work in this mode, specify the '--force-lba ' parameter. If you have installed grub at the command line but you cannot uninstall the partition where the GRUB program is located, specify the '--stage2 ' parameter. Terminal usage: terminal [--DUMB] [--no-echo] [--no-edit] [--timeout=secs] [--lines=lines] [--silent] [console] [serial] [He Rcules] [GrapHics] Description: Select a terminal. When more than one terminal is specified, press any key to continue the operation. If both the console and the serial port are specified, then the terminal in which you press the keyboard first will be selected first. If no parameters are specified, the command displays the current terminal settings; The parameter--dumb is used to designate a dummy terminal, otherwise it is vt100 compatible type; If the--no-echo parameter is used, the input characters will not be echoed on the screen; If the--no-edit parameter is used, the edit function of the bash-like will be disabled; If the--timeout parameter is used, the command waits a few seconds (specified by secs); The maximum number of rows can be specified using--lines; You can use the--silent option to turn off message display. Terminfo usage: terminfo [--name=name--cursor-address=seq [--clear-screen=seq] [--ENTER-STANDOUT-MODE=SEQ] [-- EXIT-STANDOUT-MODE=SEQ]] Description: Specifies the function of the terminal. If this terminal is VT100 compatible, you can specify the order of exchange (i.e., use/E for ESC, ^x on behalf of the control Code); If no parameters are given, the current configuration information is given. TestLoad Usage: TestLoad file Description: Reads the entire contents of a file (specified by file) in a number of different ways, and compares it to test the code of the file system. The output may seem a bit confusing, but if there is no error, the X and Y in ' i=x, Filepos=y ' will eventually be equal. If the test succeeds, you can try to load the kernel in the next step. TESTVBE Usage: Testvbe mode description: Test the VBE pattern specified (mode). Tftpserver usage: tftpserver ipaddr Description: Specifies the IP address of the TFTP server. Timeout Usage: Timeout sec Description: Sets the number of seconds to wait before starting the default menu automatically. Title usage: Title [name ...] Description: Name menu item. Unhide usage: Unhide PARTITION Description: Removes the hidden flag from the specified partition (PARTITION) by clearing the hidden flags. Uppermem usage: Uppermem Kbytes Description: Enforces that only (Kbytes) KB of upper memory is specified. of any systemThe address transformation will be canceled. Vbeprobe usage: vbeprobe [MODE] Description: detects VBE information. If a mode is specified (mode is not empty), only its information is displayed.

kernel command line parameters detailed The  linux kernel can receive certain command-line options or startup parameters when it is started. 　　You can manually pass these parameters to the kernel in such a way that the kernel does not recognize some hardware and cannot set hardware parameters or to prevent the kernel from changing the values of some parameters. 　　If you do not use the boot manager, such as directly from the BIOS or using the "CP zimage/dev/fd0" method to boot directly from the device, you cannot pass parameters or options to the kernel-this is perhaps one of the benefits of using the boot manager such as Lilo. Linux kernel parameters are a list of strings separated by spaces, usually in the following form: name[=value_1][,value_2] ... 　　[, Value_10] "Name" is a keyword that the kernel uses to identify who should be passed the value after "keyword", that is, how to handle the value, whether it is passed to the processing routine or as an environment variable or thrown to "init". 　　The number of values is limited to 10, and you can use more than 10 parameters by using the keyword again. First, the kernel check keyword is not ' root= ', ' nfsroot= ', ' nfsaddrs= ', ' ro ', ' rw ', ' Debug ' or ' Init ', then the kernel searches the bootsetups array for the registered handler that is associated with the keyword, and if the relevant registered handler is found, call these functions and pass the values following the keyword as parameters to those functions. 　　For example, you set the parameter name=a,b,c,d at startup, the kernel searches for the bootsetups array, and if "name" is found to be registered, call the "name" setting function such as Name_setup () and pass the A,b,c,d to Name_setup () execution. 　　All types, such as "name=value" parameters, if not received by the Setup function described above, will be interpreted as system-initiated environment variables, such as "term=vt100" will be used as a start-up parameters. 　　All parameters that are not received by the kernel Setup function and are not set to an environment variable are left to the INIT process, such as "single". 　　Common device-independent boot-time parameters. 　　1. Init= ... 　　Set the initialization process name of the kernel execution, if the key is not set, the kernel will try/etc/init,/bin/init,/sbin/init,/bin/sh in order, if all are not found, the kernel will throw kernel panic: error. 　　2. Nfsaddrs= ... 　　Sets the start Address of NFS from the network boot, given as a string. 　　3. Nfsroot= ... Set upThe NFS root name when the network starts, if the string is not "/", ",", "." 　　Start by pointing to "/tftp-boot" by default. 　　The above 2, 3 is very useful in the Diskless station. 　　4, no387 This option is only available when config_bugi386 is defined, some i387 coprocessor chips use 32-bit protection mode when there are bugs, such as some floating-point operations, using this parameter allows the kernel to ignore the 387 coprocessor. 5. No-hlt This option is only available when config_bugi386 is defined, and some early i486dx-100 chips have problems handling the "hlt" instruction, which cannot be reliably returned to the operating system after executing the instruction, using this option, 　　You can let the Linux system do not suspend the CPU while the CPU is idle. 　　6. Root= ... This parameter tells the kernel which device to use as the root file system when it starts. 　　For example, you can specify the root file as hda8:root=/dev/hda8. 　　7, RO and rw ro parameters tell the kernel to load the root filesystem as read-only for file system integrity checks, such as running the FSCK;RW parameter to tell the kernel to load the root file system in read-write mode, which is the default value. 　　8. Reserve= ... Keep the port number. Format: reserve=iobase,extent[,iobase,extent] ..., the I/O port used to protect a certain area is not automatically detected by the device driver. On some machines, the automatic probe fails, or the device detects an error or does not want the kernel to initialize the device with this parameter, for example: reserve=0x300,32 device=0x300, all devices except device=0x300 are not detected 　　0x300-0x31f range of I/O ports. 　　9. Mem= ... Limits the amount of memory used by the kernel. The early BIOS was designed to recognize only 64M of memory, and if your amount of memory is greater than 64M, you can indicate that if you specify more than the actual amount of memory installed, the system crash is a matter of sooner or later. 　　such as: mem=0x1000000 means that there is 16M of memory, if it is mem=0x6000000, is 96M of memory. Note: Many models use part of the memory as the BIOS mapping, so you must reserve the space when you specify the memory size. 　　You can also use Mem=nopentium to close the 4M page table on Pentium or newer CPUs, as stated in the kernel configuration. 10, panic=n By default, the kernel crashes--kernel panic will go down without restarting, you can set the downtime of the number of seconds after restarting the machine, you can also/proc/syThe S/kernel/panic file is set. 11, Reboot=[warm Cold][,[bios hard] This option is only available if config_bugi386 is defined. 　　2.0.22 's kernel reboot defaults to cool Reboot,warm reboot faster, using "Reboot=bios" to inherit BIOS settings. 12, NOSMP, and maxcpus=n This option is only available if __smp__ is defined. 　　Can be used to disable multiple CPUs or indicate the maximum number of CPUs supported. 　　Kernel development and debugging start-up parameters These parameters are mainly used in the kernel development and debugging, if you do not do similar work, you can simply skip this section. 　　1, debug Linux logging Level is more (more information can be see LINUX/KERNEL.H), generally, the log daemon klogd only the log higher than the debug level write into the disk, if this option is used, KLOGD also writes the kernel debug information into the log. 2, Profile=n in the development of the kernel, if you want to know exactly where the kernel is consumed by how much CPU clock cycle, you can use the core analysis function to set the variable Prof_shift value is not 0, there are two ways to achieve: one is specified at compile time, the other is through the " Profile= "to specify; he gives an equivalent of the smallest unit-the clock cycle; When the system executes the kernel code, the values of profile[address >;>; Prof_shift] accumulate, and you can also get the/proc/ 　　Profile gets some information about it. 3, SWAP=N1,N2,N3,N4,N5,N6,N7,N8 set eight parameters of the kernel switching algorithm: max_page_age, Page_advance, Page_decline,page_initial_age, Age_ 　　Cluster_fract, Age_cluster_min, Pageout_weight,bufferout_weight. 4, BUFF=N1,N2,N3,N4,N5,N6 set the kernel buffer memory management six parameters: Max_buff_age, Buff_advance, Buff_decline,buff_initial_age, Bufferout_ 　　Weight, buffermem_grace. Use RAMDisk parameters (only if the kernel is configured and compiled Config_blk_dEv_ram). In general, the use of RAMDisk is not a good thing, the system itself will be more efficient use of available memory, however, when starting or making a startup disk, the use of RAMDisk can easily load the floppy disk and other devices on the image (especially the installation program, during the boot process), 　　Because before you can actually use a physical disk, you must load some necessary modules, such as file system modules, SCSI drives, etc. (see my initrd-x.x.x.img file analysis-making a root file system not supported by the installer). Early RAMDisk (such as the core of 1.3.48) are statically allocated and must be ramdisk=n to specify the size of the RAMDisk; now RAMDisk can be dynamically increased. 　　A total of four parameters, two Boolean, two shaping. 　　1, load_ramdisk=n if n=1, load RAMDisk, if n=0, do not load RAMDisk; The default value is 0. 　　2, Prompt_ramdisk=n n=1, prompt insert floppy disk; n=0, do not prompt to insert floppy disk; default is 1. 　　3, ramdisk_size=n or ramdisk=n set the maximum value of RAMDisk to N KB, the default is 4096KB. 　　4, Ramdisk_start=n set RAMDisk start block number is N, when RAMDisk has a kernel image file is required for this parameter. 5, NOINITRD (only if the kernel is configured with options Config_blk_dev_ram and CONFIG_BLK_DEV_INITRD) now the kernel can support INITRD, the boot process first loads the kernel and an initialized RAMDisk, The kernel then converts the initrd into a normal ramdisk, which is the root filesystem device for read-write mode. 　　Then LINUXRC executes, then loads the real root filesystem, after which RAMDisk is unloaded and finally executes the boot sequence, such as/sbin/init. Option NOINITRD tells the kernel not to perform the above steps, even if the kernel compiles initrd, but writes INITRD data to/DEV/INITRD, but this is a one-time device