Now that all the operating systems are installed, you’re almost finished. The next step is to set up the dual-boot menu so that you can choose which OS to boot. The program that enables dual-boot is called System Commander. It needs to be installed on the MS-DOS partition. In order to install System Commander on the MS-DOS partition, we first need to make the MS-DOS partition active so that we can boot to it.
If option B reads Windows 2000, it means that System Commander picked up NT4 as Win2K, since Win2K saw the NTFS file system on the NT4 partition during installation (even though Partition Magic 5 supposedly hid it) and upgraded it to NTFS5. (It doesn’t mean that you have two Win2K installations or lost your Windows NT4 installation. NT4 is still there.)
Understanding How System Commander Works
You now have four primary partitions on your hard drive, each one containing a different operating system. In order to boot from any OS, the partition it is on must be primary (for Windows OS) and set to active. However, you can only have one partition set active at a time. Here’s why.
When you boot your machine and the initial POST (Power On Self Test) is done, the BIOS will look for the Master Boot Record (MBR), which is usually located in the first sector of the physical hard drive. This sector contains the partition table information, e.g. how many partitions there are, their size, which one is active, etc. It also contains a small program that is loaded to continue the boot process. It checks the primary active partition and loads the boot sector for that partition (the first sector of that partition), which contains the boot code specific to that operating system. As you can see, if there were multiple primary active partitions, this could never work, as it would confuse the boot code in the MBR.
To boot from different operating systems, you would have to use Partition Magic each time to set another partition active – very annoying. This is where a boot manager program like System Commander (SC) comes in. SC is installed into its own primary active partition (the DOS partition we created first) and modifies the MBR to make sure that when the system is turned on, it always loads SC first. During installation, SC also searches all partitions and identifies by the information in the boot sector of each partition what OS is installed and bootable on it. That’s how you get the boot menu every time. Once you make your selection, SC will then take the selected primary partition, set it active, hide the unneeded partitions, and proceed to boot the selected OS.
Warning! As explained before, SC modifies the MBR to ensure that SC is always loaded on bootup. However, if you run the command fdisk /mbr from DOS it replaces the custom MBR boot code with a default/generic one and it breaks the boot menu. If this ever happens to you, it is easily fixable. Boot with your MS-DOS Boot Disk. Once you’re at the DOS prompt, type C: and press Enter, then type cd sc and press Enter. Now type scin and press Enter. This will start System Commander. Select Enable/Update System Commander from the menu, then choose Enable System Commander from the next menu. This will restore the System Commander setup including the custom MBR. Exit and reboot.
Customizing System Commander
After installing System Commander (SC) and rebooting, it pretty much configures itself and works fine right away. But you can customize it bit to accommodate your needs better. You always start at the main SC screen with the OS Selection Menu. Here you press Alt-S on your keyboard (hold down the Alt key and press the key for the letter S) to get to the setup menu.
System Commander offers the following menus/options:
|Windows NT 4||Hidden||Visible||Hidden||Hidden|
The first row means that all partitions must be visible to DOS since that’s where System Commander is installed (and System Commander needs to be able to see all the options).
The second row means that the only partition visible when you boot to NT 4 will be the NT 4 partition, nothing else etc.
While it’s great to have these options, System Commander works pretty well with the default options and setups.