Reboot to restore software
Reboot to restore is a system of restore technology that enables restoring the user-defined system configuration of a computing device after every restart. The technology helps to maintain systems in their optimum working conditions and is useful especially for multi-user computing environments.

Deploying solutions based on Reboot to Restore technology enables users to define a particular system configuration as the desired state. The baseline is the point that is restored on reboot. Once the baseline gets set, the Reboot to Restore software continues to restore that configuration every time the device restarts or switches on after a shutdown.

How it works 
A reboot to restore software helps in maintaining optimal system configuration, which is quite effective in a multi-user computing environment. The technology prevents many alterations to the baseline configuration, whether user inflicted or automatic. Alterations by end users are primarily changes to system settings, installing or uninstalling of software or applications, enabling or disabling specific functionalities, and so on. The automatic alterations include cookies, add-ons and browser extensions, and several types of temporary files that often get downloaded in the background during an online session. It also rolls back malicious alterations made by malware that elusively penetrates a system and attempts to corrupt it.

Uses 
Reboot to restore software solutions simplifies maintaining optimal system configuration of devices in a multi-user computing environment such as public libraries, computer labs in educational institutes (such as K-12, colleges, universities) or training centers, public access kiosks, and so on. Because of constant use by multiple people for a wide range of purposes, these devices become susceptible to performance deterioration and malware infiltration.

During events of system malfunction or failure, it takes a considerably longer time to troubleshoot the issue using conventional practices like resetting or re-imaging. This may lead to prolonged downtime, causing poor user experience, potential loss of business opportunity, and higher maintenance costs.

Restore on reboot functionality maintains the best system configuration (pristine state) in every public-access computer without the long-drawn troubleshooting steps. Instant restoration technology empowers end-users to resolve system issues by simply restarting the device, which significantly reduces intervention by IT. The technology restores pristine configuration with every reboot, but the end user’s system achieves optimum performance. The technology helps to deliver maximum system uptime, which improves operational efficiency and resource utilization.

System administrators at corporates deploy reboots to restore solutions to create prestige environments with no constant troubleshooting. They use the software to protect the system drive and allocate a separate data partition which can store or redirect user and application data.

Software built on reboot to restore technology

Windows SteadyState 
Initially named Shared Computer Toolkit Windows SteadyState is a freeware Reboot to Restore solution offered by Microsoft and is compatible with Windows XP and Windows Vista operating systems. Microsoft discontinued Windows SteadyState in December 2010. People in educational institutes and public libraries primarily use the software.

SteadyState features a Windows Disk Protection (WDP) functionality. When it is enabled, it redirects the user-generated changes to a cache. The software had three modes—Discard, Persist, and Commit. The Discard mode clears the cache on reboot and restores the original configuration. The Persist mode retains the cache for a specific time during which the IT admins could opt to discard or commit the changes. In the Commit mode, all changes are permanently written on the hard disk as usual.

Deep Freeze 
Deep Freeze by Faronics was one of the first rollback software solutions to leverage the Reboot to Restore technology, releasing its first Windows solution in 1999, followed by a Mac OS solution in 2005.

Deep Freeze uses patented technology (, , , ) and redirects information being written to the hard drive or partition to an allocation table, leaving the original data intact. The redirected information on the allocation table is no longer referenced once the computer is restarted, therefore restoring the computer back to its original state at the disk sector level down to the last byte.

Extending the functionalities of the reboot to restore technology, the software has the provision of ThawSpaces or Thawed Partitions for permanently saving user-generated data without altering the baseline configuration. ThawSpace is a virtual space that system administrators can create within the Deep Freeze ecosystem if the hard disk does not have a partition. Content stored in the ThawSpace is retained across reboots. Thawed Partitions are the parts of a hard disk that are exempted from the effects of Reboot to Restore technology.

Other system restoration software 
Both Microsoft and Apple Inc. offer restoration tools (though not based on Reboot to Restore technology) embedded with their respective operating systems.

Windows System Restore 
System Restore is an inbuilt feature of Windows and is available in all the latest versions of the OS. It reverts system files and settings to a previous point in time without affecting personal files. When enabled, the software automatically creates Restore Points at regular intervals and before every major instance of configuration alteration like driver update or new application installation. When a device malfunctions, running System Restore rolls back the configuration to a Restore Point where the particular issue did not exist.

Reset (Windows 8) 
The Reset option was introduced with Windows 8 and is used for restoring systems to factory defaults. It re-installs the Windows OS and permanently discards all files and system settings other than the pre-installed applications.

Time Machine 
Time Machine (macOS) functions more as a backup utility than a restoration program. It creates incremental snapshots of the system configuration periodically and requires an external storage device for backing up the MacOS. This backup can later be used to restore a previous configuration as and when required. The software can also be used to restore specific items like deleted emails or older versions of files rather than the entire configuration.

Refresh 
Also introduced with Windows 8, Refresh re-installs the Windows OS but retains user files, the pre-installed applications, and those installed by the users. Running the reset option is advised only if Refresh fails to resolve the issue.

References 

MacOS security software
Utilities for Windows
Utilities for macOS
Windows security software