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Always Bootable Operating System

Authors HP INC

License CC-BY-4.0

Technical Disclosure Commons

Defensive Publications Series

July 2021


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INC, HP, "ALWAYS BOOTABLE OPERATING SYSTEM", Technical Disclosure Commons, (July 26, 2021)

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                                                  INC: ALWAYS BOOTABLE OPERATING SYSTEM

                                                  Always Bootable Operating System

                  Abstract: An I/O handler redirects writes, and subsequent reads to the same blocks, to a
                  backup disk or partition instead of the main disk or partition, to avoid persistent data
                  corruption and ensure the OS is always bootable.

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                  This disclosure relates to the field of operating systems.

                  A technique is disclosed that avoids disk corruption persisting in the disk, so that the
                  operating system (OS) is always bootable

                  In computer systems, there is a risk of a disk containing the operating system being
                  corrupted. If the disk is corrupted, it may not be possible to subsequently boot from that
                  disk. The available solutions require a backup to be securely placed somewhere, which
                  mostly corresponds to a network share, which causes the restore to take more time. In
                  addition, the availability of such a backup requires that regular backups be performed in
                  the first place.

                  According to the present disclosure, and as understood with reference to the Figure,
                  data is kept intact in the main disk until the user confirms it. All the writes and the
                  subsequent reads to the same blocks are redirected to a secondary disk to keep the data in
                  the main disk intact. Once the user confirms the data is intact, the data is synced back to
                  main disk.

                  The solution includes a main disk 10, a backup disk 20, and an I/O handler 30. The I/O
                  handler 30 is a firmware and/or OS driver that traps the reads and writes to the main

                  In some examples, the main disk 10 and backup disk 20 may be separate partitions on a
                  same disk. In some examples, the backup disk 20 may be an embedded Multi Media
                  Card (eMMC) or solid-state drive (SSD). The backup disk 20 or partition is typically
                  smaller in size, such as for example 32 GB, than the main disk 10.

                  In operation, the IO handler 10 traps the reads and writes 40 and redirects the data to the
                  appropriate disk (or disk partition). Any writes to the blocks in the main disk 10 will be
                  trapped and redirected to the backup disk 20. Any subsequent reads to those blocks also
                  will be redirected to the backup disk 20. All reads to the unmodified blocks will still be
                  directed to the main disk 10. This way the main disk 10 will remain unmodified and not
                  be affected by any application installation or virus, while the user will get the new or
                  modified data from the backup disk 30.

                  For syncing the data back to the main disk 10, a "sync and shutdown" button is provided.
                  A "discard" button for discarding the data may also be provided.

                  Once the user is done with the current session and happy with the application installed
                  and how the app and OS behave, they click the "sync and shutdown" button.

                  If the user experiences a problem, they can choose to discard the data and reboot to bring
                  the OS back the previous state. In some examples, before restarting the OS, they can
                  choose to backup any data that is created in the same session to a separate partition, or to
                  an external drive or network. Data can also be discarded during the boot, in case the user                                                                      3
                                                  INC: ALWAYS BOOTABLE OPERATING SYSTEM

                  doesn't sync or discard the data, and if an issue with the boot occurs such that it is not

                  In some examples, the data can be stored in a host protected area on the hard disk to hide
                  it from the OS, or it can be stored in a separate small disk such as a 32GB SSD in a
                  laptop with RAID configuration for speed of access.

                  The disclosed technique advantageously avoids data corruption persisting in the disk and
                  the OS becoming unbootable and provides faster restore from a disaster state. It enables
                  easy refreshing of disk that are used, for example, in kiosks, exam centers, and the like,
                  where fresh image/data is required for each user. Use of an SSD as the backup drive 20
                  speeds up disk writes as compared to a slower main drive 10.

                  Disclosed by Reny Paul, HP Inc.

Published by Technical Disclosure Commons, 2021                                                                4
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