October 3, 2006

Super Grub Disk delivers easy boot record recovery

Author: Bruce Byfield

Super Grub Disk (SGD) is a specialty rescue CD for emergency repairs on boot sectors. Despite its name, SGD not only manipulates the Grand Unified Bootloader (GRUB), but also works with the content of other master boot records as well. Available in English, French, and Castillian Spanish, SGD also works with a variety of operating systems and supports all the basic options needed to manipulate how a hard drive boots.

Rather than its functionality, SGD's name apparently comes from the fact that its interface consists of several hierarchies of GRUB menus. But instead of the partitions and kernels that you are used to seeing in an installed system, the menu items are recovery options. The result is a highly serviceable interface within a text-based environment that requires almost no input from users other than the selection of an option. Both basic and advanced menus are available, the main difference being that the advanced menus give you the option of more input into the available actions. Both menu interfaces gives you the option to go back to a previous menu at the top of each list of items.

The top level menu summarizes the software's functionality. SGD offers full support for GRUB, and LILO support is currently in beta. The CD is designed with GNU/Linux and Windows in mind, but also supports HURD and OpenSolaris in its Special menu. Both GRUB and LILO can be reinstalled in the master boot record or on another partition, or alternatively, uninstalled, while GRUB can usually be booted using the existing configuration on the hard drive -- although not, currently, if the /boot directory is on its own partition.

Similarly, Windows -> Fix Boot offers the equivalent of fdisk /mbr to restore a system for booting Windows. Other Windows options include booting from a second partition or second hard drive -- two unusual circumstances in Windows.

Alternatively, users can manipulate partitions regardless of of operating systems, making them active, hidden, or unhidden as needed. These options can help restore access to a system. In particular, they can ease the problem of installing Windows on a system that already has a GNU/Linux distribution or another version of Windows installed. All you need to do is hide the partitions that already have operating systems on them, then unhide them after the latest installation and select GNU/Linux -> Fix Boot (GRUB) to restore access to all operating systems.

Other potential uses for SGD are listed in the project's documentation. If necessary, users can also resort to the Special menu to set the keyboard used, or even to choose one of several color schemes in which to read to SGD -- an option which might seem unnecessary until you remember the problems of color-blindness.

SGD's functionality is welcome in itself. However, SGD is also reminiscent of the system hardener Bastille, in that its interfaces are designed to educate users while performing practical functions. Before each menu displays, SGD shows a screen that summarizes the menu items, and often suggests when they would be useful. For instance, Boot & Tools -> Hide Partition is recommended to hide partitions when you install multiple versions of Windows. In some cases, the program gives even more advice, as in Miscellanea -> Boot Windows, where SGD advises "Use this only if you do not have a Windows Cd or when you've used the options uninstall Grub from the MBR [and] Activate partition (1st one on 1st hard disk) and Windows still does not boot."

In the English version, these summaries and pieces of advice are mildly stilted, but understandable. However, each page should be prefaced with a warning that users should take notes, because, given the interface of linked GRUB menus, returning to a summary requires backing out of the current menu, then selecting the menu again from its parent menu.

Currently at version 0.9428, SGD still has a few omissions. So far, it lacks the backup tools mentioned in the notes for the menu items in Miscellanea -> Boot Windows, as well as the ability to manipulate NTFS partitions. Considering its goal of educating users, it would also benefit from a summary of the naming conventions for partitions, both in the supported operating systems and in GRUB. There is enough inconsistency in the conventions to confuse the inexperienced, and suggesting, as SGD does once or twice, that users try options until they find one that works is hardly calculated to soothe panicked novices who are desperate to restore their systems.

I would also like to see SGD on a disk with GNU Parted or even one of its GUI offshoots, which would create a complete rescue disk for partitions. Since SGD's files are only about 500KB in size, I suspect that there won't be a long delay before someone follows the instructions in the FAQ to add SGD to another CD image or those in the USB_readme.txt included in the CD image to add SGD to a USB flash drive -- either way providing the complete partition rescue tool I have in mind.

However, even without these enhancements, Super Grub Disk is worth adding to your collection of rescue CDs. You can never have too many rescue CDs in a crisis, and SGD not only delivers a thorough selection of options, but also the guidance that even experienced users can appreciate when they're too concerned about inaccessible data to remember the steps they need to recover.


Bruce Byfield is a course designer and instructor, and a computer journalist who writes regularly for NewsForge, Linux.com and IT Manager's Journal.

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