The main function of GRUB is placed in a single file grldr, while the boot loader is placed in another file grldr. At startup, boot code in grldr. Using this scheme, the location of boot file is no longer fixed, users can move it across partition boundary without causing booting problems. The other is grub.
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This guide contains many new and previously undocumented features. New eBook PDF - ' Getting started with grub4dos ' version - complete guide with exercises and full command reference. The article below is now old and outdated. The new eBook contains an easy way to make nice menus using the latest version of grub4dos. I highly recommend that you download and use only this version of grub4dos 0. I strongly recommend 0. GitHub 0. Grub4dos version 0. This tutorial is an introduction on how to make a bootable grub4dos USB drive.
Grub4dos allows you to make a multiboot multipass drive. Grub4dos boot code can be installed either onto the MBR Master Boot Record, on the first sector of the disk and boot track first track of a drive, or the partition boot record. It consists of two parts or stages.
The first part is the boot code which is in the first sector and some of the following sectors of the boot drive or partition. Once this code is run by the CPU, the code then looks for a file called grldr. The grldr file needs be in the root and on the same boot partition if the boot code is installed onto the partition boot record PBR - start of the partition.
If the boot code was installed onto the MBR, then the root of all devices will be searched to find the grldr file. See here for more details. Grub4dos can boot an OS or executable from a 'flat file' structure or from disk image files or even ISO files. It can even load images into memory ram drive and run the OS from there! Most of the tutorials on this website use grub4dos. Grub4dos can run grub4dos batch files which must start with!
BAT and grub4dos executables and supports environment variables. It is a very powerful environment and is under constant development and improvement by chenall, tinybit, yaya and many others. There is an active forum on reboot. By convention not mandatory , grub4dos programs may have the file extension.
If you have never used grub4dos before, I will give you a quick 'How to' introduction so you can make a working USB pen drive with which you can experiment. I recommend that you always use the latest version of RMPrepUSB to install grub4dos rather than using grubinst or bootice for two reasons:.
If you are having problems booting to grub4dos on some very old systems try FlashBoot to prepare your USB drive. Here are two Grub4dos - Part 1. Grub4dos - Part 2. Grub4dos internal variables and Functions Lots of menu. Linux users can install grub4dos using BootIce.
MS-DOS 4. Tip: Some systems give a 'flashing cursor' when they boot from grub4dos installed to the MBR. Note that grub4dos consists of two parts as explained previously. Part 1 is the boot code which does not actually exist as a file and so cannot be easily seen. It's code can be located either in the Master Boot Record first 31 sectors on a disk or in the Partition Boot Record first sectors at the start of a partition.
This is written to the disk when you click on the 'Install grub4dos' button and grubinst. Part 2 is the main grub4dos code which is loaded by the Part 1 boot code. Part 2 is just the file grldr which should be located in the root of your bootable drive partition. If you wish to use a different version of grub4dos, simply replace the grldr file on the USB boot drive with your different grldr file. Once the the glrdr file loads into memory and runs, grub4dos will look for a menu file to parse and run grldr includes a pre-boot configfile which then looks for a menu.
The menu is in the form of a text file named menu. The search path that grub4dos uses to find a menu. The grldr file contains it's own small pre-boot menu bytes which includes the commands to search for the menu.
This embedded menu can be changed if you wish. If a menu. You can type in most of the grub4dos commands at the grub4dos command prompt such as help. A menu file consists of two sections - all commands before the first title command are executed, in sequential order, as soon as the menu file is loaded.
When the first title command is found, any further lines are interpreted as menu entries each menu entry starts with a title command word followed by one or more command lines. Note: If your menu uses iftitle commands, all iftitle [xxxxx] lines are evaluated and any commands inside the [ When a user selects a menu entry and presses [Enter], the commands below the title command are executed by grub4dos until the next title command is found or the end of file is found.
When the next title command is found or the end of file is reached grub4dos will automatically issue a boot command and CPU control will be passed to whatever code was loaded by the previous menu instructions. Note: The menu. Hak5 video on menu. You should now see a BIOS boot screen window appear briefly and then a window like this:. It is possible to spice up this menu and make it look better. Let us change the text and background colour, set a second timeout, set a default menu choice if no key is pressed and add a background wallpaper using a.
Note: A line starting with is a comment line - text which follows a symbol or pretty much any character! Note : foreground and background commands will only work in old 16 colour graphicsmodes e.
It is best to avoid these commands and use the color command instead - see below. You can prefix most colours with 'blink-' to make them flash.
Note that blink only works in textmode e. Also you cannot have light blinking background colours, e. Equally color 0x91 will set blinking blue text on a blue background i.
If you issue the command echo -h at the grub4dos command console, all the possible values from 0x00 to 0xff are listed in a table:. Later versions of grub4dos June and later can also understand individual colour settings, e. Only the standard and highlight colours accept a background colour setting. For commands that are above any menu title command i. For lines which follow after a 'title' line, white space and graphics characters are ignored unless they follow a command word - e.
Nearly all grub4dos commands are and must be lower case e. It is also recommended to use 8. Also be aware that files within a CD or ISO image may be uppercase when accessed by grub4dos, even if they appear as lowercase when viewed in Explorer. A File Name with Spaces. If the file 'A File with Spaces. If you just want to add a nice background, skip the next bit and jump to the ' High Colour and High Resolution Backgrounds ' section below.
Note that the menu example above has a ' splashimage ' statement. For older versions of grub4dos this command can only use a 14 colour xpixel image to use as a background image if you do not change the graphicsmode and leave it set to the default mode. This menu text will be laid over the background image.
If you are using splashimage with higher resolution images which is supported on versions of grub4dos , use the new color command see above. Make your own splashimage colour background file You can use 7Zip or Gzip to create a compressed 14 colour.
The image needs to be in xpm format it can be compressed to. The image must have only 14 colors or less. The conversion is quite good and probably better than you could do manually using a bitmap editor tool! Note: Splashimage also can load highly compressed. Note: The XPM format no longer supported by grub4dos! Find your. Then use 7Zip or Gzip to compress it as a. Note: The XPM format is no longer supported by grub4dos. You can reduce the colours in Gimp by selecting Image, Mode, Indexed and entering 14 as the maximum colors if it does not prompt you for the number of colours, select RGB and then select Indexed.
Click Convert. Save this file as a XPM, then gzip it. Right-click the file and use 7zip - add to archive - choose. Under Windows 7, I had some trouble with this method and could not get it to work maybe you can! With the newer versions of grub4dos included and used by RMPrepUSB , you can use bit colour or bit or bit colour images with splashimage. Note that the background colours for normal, heading, border and help text will be ignored as the background will always be set to transparent,.
You can also use bit and bit colour values if the display is in graphics mode - e. The latest 0.
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Grub4dos Guide - Map Command
There are two distinct types of mapping, direct and memory. If using direct mapping to create a virtual device from a disk image, then the image file must be contiguous not fragmented. Either of the following programs can be used to defragment a file that is not contiguous - contig or wincontig. In memory mapping the image file can be non-contiguous. Available system RAM will restrict the size of any image mapped to memory. The "map" process is implemented using INT 13 - any disk emulation will remain accessible from an OS that uses compatible mode disk access, e. DOS and Windows 9x.
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This guide contains many new and previously undocumented features. New eBook PDF - ' Getting started with grub4dos ' version - complete guide with exercises and full command reference. The article below is now old and outdated. The new eBook contains an easy way to make nice menus using the latest version of grub4dos. I highly recommend that you download and use only this version of grub4dos 0. I strongly recommend 0. GitHub 0.