# US 2014/0195791 A1 · Methods and systems for instant restore of system volume > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0195791 A1 - Document ID: US20140195791A1 - Status: Published application - Kind: A1 - Application number: 13/736,664 - Filed: 2013-01-08 - Published: 2014-07-10 - Earliest claimed: 2013-01-08 - Assignees: Symantec Corporation - Applicants: Symantec, Inc. - Inventors: Ravindra TELI; Mohammad Eliyas SHAIKH; Chirag DALAL - Web page: https://patentgrep.com/patent/US20140195791A1 ## CPC - G06F 11/1417: {Boot up procedures} - G06F 11/1469: {Backup restoration techniques} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract Techniques are disclosed for restoring a system volume on a computing system without requiring the system volume to be fully restored prior to being used or requiring the use of a dedicated recovery environment (e.g., the WinPE or BartPE environments). Instead, the computing system is booted directly from the restore image or by redirecting I/O interrupts to the restore image. That is, when user initiates a restore process, the system boots from the backup itself. Once booted, a background process can complete the restore process. ## Claims ### Claim 1 A computer-implemented method for restoring a system volume from a backup image, the method comprising: prior to launching a boot loader on a computing system, receiving an indication to restore the system volume from the backup image; redirecting an interrupt associated with disk I/O to a redirector function configured to perform read operations directed to the system volume from the backup image; and launching the boot loader, wherein the boot loader is configured to load an operating system stored in the backup image. ### Claim 2 (depends on 1) The method of claim 1, wherein the interrupt is an INT13 interrupt on an x86 architecture. ### Claim 3 (depends on 1) The method of claim 1, further comprising: after the boot loader turns over control for disk I/O to the operating system, launching a disk filter driver configured to perform read operations directed to the system volume from the backup image and to perform write operations by writing to the system volume. ### Claim 4 (depends on 3) The method of claim 3, wherein the disk filter driver is configured to complete restoring the system volume from the backup image by copying disk sectors from the backup image to the system volume. ### Claim 5 (depends on 1) The method of claim 1, wherein the backup image is stored in a virtual hard disk (VHD) formatted file. ### Claim 6 (depends on 1) The method of claim 1, wherein the backup image is stored on a local partition of a storage drive on the computing system. ### Claim 7 (depends on 1) The method of claim 1, wherein the redirector function performs a copy-on-read process to copy data read from the backup image to the system volume. ### Claim 8 A computer-implemented method for restoring a system volume, the method comprising: prior to launching a boot loader on a computing system, receiving an indication to restore the system volume from a virtual hard disk (VHD); launching a disk filter driver configured to attach to a driver configured to perform disk I/O from the VHD, wherein the disk filter driver is configured to perform read operations directed to the system volume by reading from the VHD and to perform write operations by writing to the system volume; and after booting an operating system stored on the VHD completing the restoring of the system volume from the backup image by copying disk sectors from the VHD to the system volume. ### Claim 9 (depends on 8) The method of claim 8, further comprising, after restoring the system volume, transitioning the disk filter driver to a pass through mode which directs disk I/O read and write requests to the restored system volume. ### Claim 10 (depends on 8) The method of claim 8, wherein the disk filter driver is configured to restore the system volume, at least in part, by performing a copy-on-read process for disk I/O reads directed to the VHD. ### Claim 11 A computer-readable storage medium storing instructions, which, when executed on a processor, perform an operation for restoring a system volume from a backup image, the operation comprising: prior to launching a boot loader on a computing system, receiving an indication to restore the system volume from the backup image; and redirecting an interrupt associated with disk I/O to a redirector function configured to perform read operations directed to the system volume from the backup image; and launching the boot loader, wherein the boot loader is configured to load an operating system stored in the backup image. ### Claim 12 (depends on 11) The computer-readable storage medium of claim 11, wherein the interrupt is an INT13 interrupt on an x86 architecture. ### Claim 13 (depends on 11) The computer-readable storage medium of claim 11, wherein the operation further comprises: after the boot loader turns over control for disk I/O to the operating system, launching a disk filter driver configured to perform read operations directed to the system volume from the backup image and to perform write operations by writing to the system volume. ### Claim 14 (depends on 13) The computer-readable storage medium of claim 13, wherein the disk filter driver is configured to complete restoring the system volume from the backup image by copying disk sectors from the backup image to the system volume. ### Claim 15 (depends on 11) The computer-readable storage medium of claim 11, wherein the backup image is stored in a virtual hard disk (VHD) formatted file. ### Claim 16 (depends on 11) The computer-readable storage medium of claim 11, wherein the backup image is stored on a local partition of a storage drive on the computing system. ### Claim 17 (depends on 11) The computer-readable storage medium of claim 11, wherein the redirector function performs a copy-on-read process to copy data read from the backup image to the system volume. ### Claim 18 A computer-readable storage medium storing instructions, which, when executed on a processor, perform an operation for restoring a system volume, the operation comprising: prior to launching a boot loader on a computing system, receiving an indication to restore the system volume from a virtual hard disk (VHD); launching a disk filter driver configured to attach to a driver configured to perform disk I/O from the VHD, wherein the disk filter driver is configured to perform read operations directed to the system volume by reading from the VHD and to perform write operations by writing to the system volume; and after booting an operating system stored on the VHD completing the restoring of the system volume from the backup image by copying disk sectors from the VHD to the system volume. ### Claim 19 (depends on 18) The computer-readable storage medium of claim 18, wherein the operation further comprises, after restoring the system volume, transitioning the disk filter driver to a pass through mode which directs disk I/O read and write requests to the restored system volume. ### Claim 20 (depends on 18) The computer-readable storage medium of claim 18, wherein the disk filter driver is configured to restore the system volume, at least in part, by performing a copy-on-read process for disk I/O reads directed to the VHD. ### Claim 21 A system, comprising: a processor; and a memory storing code, which, when executed on the processor, performs an operation for restoring a system volume from a backup image, the operation comprising: prior to launching a boot loader on a computing system, receiving an indication to restore the system volume from the backup image, redirecting an interrupt associated with disk I/O to a redirector function configured to perform read operations directed to the system volume from the backup image, and launching the boot loader, wherein the boot loader is configured to load an operating system stored in the backup image. ### Claim 22 (depends on 21) The system of claim 21, wherein the interrupt is an INT13 interrupt on an x86 architecture. ### Claim 23 (depends on 21) The system of claim 21, wherein the operation further comprises: after the boot loader turns over control for disk I/O to the operating system, launching a disk filter driver configured to perform read operations directed to the system volume from the backup image and to perform write operations by writing to the system volume. ### Claim 24 (depends on 23) The system of claim 23, wherein the disk filter driver is configured to complete restoring the system volume from the backup image by copying disk sectors from the backup image to the system volume.