FreeLoader (Sometimes FreeLdr) is the ReactOS bootloader. It can also function as a bootmanager for multiple OSes.
FreeLoader is composed of two files, an executable (FREELDR.SYS) and a configuration file in Windows INI format (FREELDR.INI), and a bootsector to load the files. The two files are copied to the root directory (:\ or / depending on the OSes path notation) of the active partition.
Method of installation by ReactOS
The FreeLoader boot code can be installed in many ways, depending on the pre-existing operating system. The setup logic tries the following steps in order:
Windows NT OS
If the Windows NT/2000/XP/2003 boot loader (NTLDR) is found on the active partition, the existing boot manager is configured to boot ReactOS. The FreeLoader boot code is written to a file named BOOTSECT.ROS in the root of the active partition, and an entry named "ReactOS" is added to BOOT.INI pointing to BOOTSECT.ROS.
The NT boot manager is detected by the presence of the files NTLDR and BOOT.INI in the root directory of the active partition. If Windows is set to hide system files, you may not be able to see these files.
To uninstall FreeLoader, delete the file BOOTSECT.ROS and remove the "ReactOS" entry from the hidden BOOT.INI file.
DOS / 9x
If MS-DOS or Windows 95/98/ME is found on the active partition, the original boot sector is saved to a file named BOOTSECT.DOS in the root directory of the active partition. The FreeLoader boot code is then written to the boot sector of the active partition. FreeLoader thus becomes your primary boot manager, and from its boot menu you will be able to boot both ReactOS and Windows or DOS.
MS-DOS and Windows 95/98/ME are detected by the presence of the files MSDOS.SYS and IO.SYS in the root directory of the active partition.
To uninstall FreeLoader, boot from a MS-DOS or Windows Restore floppy disk, and run the command "SYS C:". After this, the BOOTSECT.DOS file can be safely deleted.
If none of the known operating systems are found on the active partition, the original boot sector is saved to the file BOOTSECT.OLD in the root directory of the active partition. The FreeLoader boot code is then written to the boot sector of the active partition. FreeLoader thus becomes the primary boot manager. Note that you will have to edit the FREELDR.INI configuration file by yourself to boot the pre-existing operating system, because FreeLoader has no knowledge of how to do it.
To uninstall FreeLoader, restore the boot sector of the active partition from the BOOTSECT.OLD file. The details on how to do so are dependent on the operating system you are running
Note: If the active partition uses a FAT32 filesystem, the boot code does not fit into a single sector. Microsoft uses sectors number 0 and 12, while FreeLoader uses sectors number 0 and 14, so there should not be any conflicts with existing boot loaders.
- HOWTO/boot FreeLoader from GRUB - For people loading FreeLoader and hence ReactOS from a bootmanager