| The System Restore feature of MicrosoftÂ(R) | | | | re->KeysNotToRestore? If the information also resides |
| WindowsÂ(R) XP (the operating system | | | | in files, have you ensured System Restore will not |
| previously known as MicrosoftÂ(R) Whistler) | | | | restore these files by calling out |
| enables administrators to restore their PCs, in the | | | | re->filesnottobackup? |
| event of a problem, to a previous state without losing | | | | For backup utilities, does it check the files specified in |
| personal data files (such as Word documents, | | | | NTFilesnottobackup and, if listed, not back them up? |
| drawings, or e-mail). System Restore actively monitors | | | | System Restore datastores should not be backed up |
| system file changes and some application file changes | | | | and are specified in NTFilesnottobackup. System |
| to record or store previous versions before the | | | | Restore only monitors on first write, so when backing |
| changes occurred. With System Restore, users never | | | | up files, using the operation "open to backup" will not |
| have to think about taking system snapshots as it | | | | cause additional overhead from System Restore. |
| automatically creates easily identifiable restore points, | | | | Does the backup utility have undo functionality in the |
| which allow users to revert the system back to a | | | | event of a cancelled or failed recovery? If not, calling |
| previous time. Restore points are created at the time | | | | the System Restore API (14-Recovery) will ensure |
| of significant system events (such as application or | | | | users have a restore point immediately before a |
| driver install) and periodically (every day). Additionally, | | | | recovery so that users can revert an undesirable or |
| users can create and name their own restore points | | | | cancelled recovery. (See SRSetRestorePoint in the |
| at any time. System Restore has an automatic restore | | | | System Restore section of the Platform SDK.) |
| point space-management feature that purges the | | | | Automatically Created Restore Points |
| oldest restore points to make room for new ones, so | | | | Restore points are created to allow users to choose |
| that a rolling safety net is always kept under the user, | | | | previous system states. Each restore point gathers |
| enabling the user to recover from recent undesirable | | | | the necessary information needed to restore to a |
| changes. | | | | precisely chosen system state. They are created |
| If users experience system failure or another | | | | before key changes are made to the system. Since |
| significant problem, they can use System Restore | | | | these restore points are automatic, users don't even |
| from SafeMode or Normal Mode to go back to a | | | | have to think about creating manual restore points |
| previous system state, restoring optimal system | | | | (unless they choose to). The following topics describe |
| functionality. System Restore will not revert user data | | | | the triggers that cause this feature to create a restore |
| or document files, so restoring will not cause users to | | | | point. |
| lose their work, mail, or even browsing history and | | | | Event-triggered restore points |
| favorites | | | | System Restore will automatically create a restore |
| Detail | | | | point before the following events: |
| System Restore is enabled by default and will run | | | | Application installations (provided the application utilizes |
| upon the successful completion of either the Windows | | | | a current installer that is System Restore |
| XP Professional or Home version installation. System | | | | RestorePT.API compliant). In the event the application |
| Restore uses 400mb or 12% of the Hard Drive | | | | causes harm to the user's system, choosing a restore |
| (whichever is greater) by default. It requires a minimum | | | | point before the application was installed allows the |
| of 200 MB of space available on the system partition. | | | | user to roll the system state back to the time before |
| If there are not 200 MBs available, System Restore | | | | the installation of the application, if needed. |
| will install disabled and will enable itself automatically | | | | AutoUpdate installation. The Auto/Industry Update |
| once the required disk space is created. | | | | feature of Windows XP provides an easier way for |
| Design Overview | | | | users to download critical Microsoft |
| System Restore monitors a core set of system and | | | | WindowsÂ(R) updates in an unobtrusive way. |
| application files, recording and sometimes copying | | | | Once the update is downloaded, the user is presented |
| states of these files before changes are made. | | | | with the opportunity to install the update on the user's |
| Monitored files include those that are not in excluded | | | | system. When the user chooses to install the update, |
| directories (My Documents) and that do not have | | | | the System Restore feature will create a restore point |
| known data file extensions (such as .doc). System | | | | before the actual installation of the update begins. If the |
| Restore automatically creates restore points; no user | | | | user restores after files are downloaded but before |
| intervention is required. To create a restore point, | | | | the installation of the update occurs, the downloaded |
| System Restore takes a full snapshot of the registry | | | | files will not be removed by the restore operation. |
| and some dynamic system files. For a list of file | | | | Restore operation. If a user, for example, accidentally |
| extension types, which are included (monitored and | | | | chooses the wrong system state to restore back to, |
| restored), refer to the Monitored File Extensions list in | | | | the user can, by choosing a restore point before this |
| the System Restore section of the Platform SDK. | | | | operation, undo the restore operation. The user can |
| To restore a system, System Restore reverts file | | | | then choose the correct restore point. The restore |
| changes done to monitored files, recapturing the file | | | | operation itself will create a restore point for undo |
| state at the time of the selected restore point. It then | | | | purposes. |
| replaces the current registry with the "snapshotted" | | | | Microsoft Backup Utility Recovery. Before Microsoft |
| one, which coincides with the selected restore point. | | | | Backup Utility performs a backup recovery, System |
| Some security and dynamic rights and authentication | | | | Restore will create a restore point. In the event the |
| information from the current registry is then copied to | | | | recovery is cancelled or leaves the system in an |
| the restored registry. The next sections will discuss | | | | undesirable state, users can use this restore point to |
| in-depth how this feature works. To achieve the | | | | revert the system to the point before the recovery |
| desired behavior after a restore, application developers | | | | started. |
| should answer the following: | | | | Unsigned driver installation. Unsigned device driver |
| Do key application binaries to be protected by System | | | | installations are detected by the INF installer of |
| Restore contain extensions consistent with those | | | | Windows. Before the installation proceeds, a restore |
| included in the portion of the System Restore | | | | point is created so in the event the installation results in |
| Monitored File Extensions list in the Platform SDK? | | | | a harmful impact to the system, users can restore to |
| Are user-editable files, or intended personal data files | | | | the point immediately before the unsigned driver |
| (for example, .pdf, .xls, .htm) named in such a way that | | | | installation. |
| they will not be monitored as included extension | | | | Manual Restore points. At any time, users |
| types? For example, have you named a file extension | | | | (administrator/owner users only) may create and |
| .ini that a user can modify as a personal data file? If so, | | | | name an on-demand restore point. This is useful to |
| this will impede the perception of your product's | | | | create a "checkpoint" to return to preceding a |
| performance, as well as cause the user to lose work | | | | particularly risky change, before a shared system is |
| as a result of a restore. (See the Monitored File | | | | left to other users, or at a particular state the user |
| Extensions list in the System Restore section of the | | | | perceives to be optimal. |
| Platform SDK.) | | | | What's Restored and What's Not |
| Is there key information stored in the registry which, | | | | Restored |
| following a restore, will prevent users access to their | | | | Registry |
| personal data files or their application? If so, is there a | | | | Profiles (local only-roaming user profiles not impacted |
| mechanism by which the user can again download or | | | | by restore) |
| install an application without having to pay for it again? | | | | COM+ DB |
| Or have you specified the registry keys where this | | | | WFP. |
| information is stored in the registry under | | | | |