RollBack Rx is a system drive restoration third party disk utility for Microsoft Windows, and is unique in that it uses a sector mapping algorithm and incremental sector redirection to capture and manage its snapshots. This product is marketed under other names and price points such as EAZ-FIX.
How it works
RollBack Rx installs to the hard drive's master boot record, which loads prior to the Windows operating system, which allows the hard drive to be reverted to a previous snapshot state even in the event that Windows is unable to boot. The user can also select to revert to a snapshot from within Windows, which requires a reboot or logoff to take effect. Due to its sector based mapping, RollBack Rx does not recreate files or folders into a temporary drive space resulting in a larger capacity of incremental snapshots and faster snapshot times. The RollBack Rx snapshots can be taken manually, on a schedule or when a particular file is executed.
A snapshot is a bit-for-bit map of the hard disk sector. It is a record of how the PC's hard drive is configured at the time a snapshot is taken. The snapshot includes all files including system, data, programs, settings, the registry, wallpaper, icons, etc.
Incremental sector redirection
RollBack Rx's core algorithm is based on incremental sector redirection. Windows operates at a cluster level, which consists of multiple disk sectors. RollBack Rx works at the disk sector level.
When a snapshot is taken, RollBack Rx freezes sectors to their current data. If Windows attempts to update a particular sector, RollBack Rx grabs the write and redirects it into unprotected sectors. If Windows attempts to delete the sector, Rollback Rx intercepts the delete. Additional snapshots freeze only those sectors that have been written since the last snapshot. The snapshots form a tree structure, each one based on some previous one. If a snapshot is deleted on which another snapshot is based, the updated size of the dependent one will be greater than before.
It can be beneficial to disable RollBack Rx prior to using any Windows defragmentation utility, as file relocations are treated by RollBack Rx as relatively large data changes and can therefore cause large snapshots. The current version 9.1 does not support any third party disk defragmenter. However, defragmentation can be carried out without disabling RollBack Rx, and the data used can be freed by "re-baselining" (which will cause the removal of all snapshots taken so far).
RollBack Rx does not support RAID or any server-based operating systems. RollBack Rx will not be accessible at bootup if the Master Boot Record is erased or altered. RollBack Rx, being a Windows application, cannot protect the hard drive from changes occurring under DOS or other operating systems (such as Linux).