ERDisk - Creator of Emergency Repair Disks
Frequently Asked Questions

What is ERDisk?

Why do I need Emergency Repair Disk?

Why 'Rdisk' command does not solve Enterprise Emergency protection and recovery needs.

What does ERDisk do?

Performance and scalability.

Required system resources and network overhead.

Can I create ERDs for all my computers simultaneously?

How do I schedule ERD creation? Command line syntax.

How do I know if the process is completed successfully or with errors? Can I be notified about the results?

Log File. Troubleshooting.

ApplyERD Tool.

What do I do if ERD does not fit onto a floppy disk?

Security issues

Is ERDisk Y2K-compliant?

How do I use Emergency Repair Disk to restore original system settings?

How is ERDisk licensed?

For additional assistance use ERDisk on-line Help file. Download ERDisk White Paper.

What is ERDisk?

ERDisk is a unique software product in the Backup/Recovery category. ERDisk automatically updates and creates Emergency Repair Disks for one or a group of Windows NT servers and workstations remotely and across an entire network. Emergency Repair Disks can be stored anywhere on the network. Computers in a distributed network can be logically grouped, and ERDs for different groups of computers can be stored in different locations.

ERDisk provides effective system protection and recovery and requires minimum storage resources, network overhead and administrator involvement. With the smart Scheduler Service ERDisk automates the process of creating and updating ERDs to the point of ‘set and forget it’ for the entire network.

Why do I need Emergency Repair Disk?

When Windows NT fails and fault recovery becomes necessary, Emergency Repair Disk (ERD) is the first tool that should be utilized to restore the system. ERD represents an image of the most important system files and Windows NT registry.

To reflect system changes, repair information must be updated and a new Emergency Repair Disk created any time you change system configurations in any significant way, such as changing software, hardware or network configurations, installing new software, etc. Creating Emergency Repair Disk is not a replacement for regular backups, nor is a full backup a replacement for ERD.

The following is taken from Microsoft KB Article Q156328
Description of Windows NT Emergency Repair Disk:

"Maintaining a current ERD is just as important as having a current system backup. When system configuration changes are made (such as installing new software or changing software configuration, altering network configuration, hardware changes, operating system updates) you should update your ERD... A current Emergency Repair Disk is your most valuable tool in recovering information that you need to start your system. The Emergency Repair Disk is intended to provide just enough recovery to restore a system to a bootable state and is not a replacement for regular backups... You can use the Emergency Repair Disk to replace damaged system files, restore damaged or incorrect registry information, and rebuild the startup environment."

Good examples of when ERDs must be created are described in the REPAIR ISSUES section of the Microsoft KB Article ID: Q143475 Windows NT System Key Permits Strong Encryption of the SAM

Windows NT 'Rdisk' command.

Windows NT Server and Windows NT Workstation include the RDISK command for building and maintaining ERD. However, there are several problems in using the native RDISK command.

1. The RDISK command cannot be performed remotely, but must be used at the console. The administrator must go to each server and workstation and perform the ERD creating procedure for each computer. Depending on the number of servers and workstations, this could be an extremely time-consuming process. In some cases, it might not even be feasible for an administrator to go to a remote location.
2. Physical ERDs must be created and stored in a central, secure location. RDISK command does not provide an option for storing ERD in any place other than on a floppy disk. In most cases it is much more convenient to store multiple ERDs on a hard disk of a secured computer somewhere on the network. In a distributed network, this could include several locations.
3. In many cases, the size of Emergency Repair Disk files exceeds the size of a floppy disk (1.44-Mb), and a physical ERD cannot be created. In addition to storing other information, Emergency Repair Disk stores security information. A good example of when ERD files do not fit on a floppy is when a server or workstation has many users.
4. The standard procedure for system recovery is time-consuming and requires three Windows NT startup disks, ERD (on a floppy disk) and CD-ROM with Windows NT original setup files. The recovery procedure cannot be simplified or performed remotely.

What does ERDisk do?

ERDisk installs an ERDisk agent on every selected computer and runs Windows NT command "rdisk -s" locally on those computers. (Note: ERDisk uses 'rdisk' command with switch S to save the security database). The process of creating ERD is initiated on all selected computers simultaneously. After ERD is created the agent skips steps for formatting a floppy disk and transferring updated files to a floppy disk. Instead, ERDisk copies new files to a specified directory on the network. After the process is completed the agent is automatically removed. The administrator can create a physical ERD any time by copying the files, including hidden and system files, to a floppy disk.

Performance and scalability.

ERDisk provides excellent performance. It is easily scalable to manage any number of servers and workstations. The process of creating ERD is started simultaneously on all selected computers, so it takes approximately the same time to create ERD for one or one hundred computers.

Required system resources and network overhead.

One of the unique features of ERDisk as a software product in the Backup/Recovery category is that it requires minimal system resources and storage space. Also, with ERDisk you do not need to install, run and maintain any client software. ERDisk does not create any significant load on network traffic.

ERDisk requires minimal administrator involvement, providing excellent system protection and emergency recovery.

Can I create ERDs for all my computers simultaneously?

Yes, you can. The ERDisk Graphical User Interface (GUI) allows you to select another Windows NT domain, add or remove computers from a list, or load a customized list of computers from a text file which can include any computer from various domains.

Also, to provide simplified distributed network management, servers and workstations can be logically grouped by type, location or other parameters defined by an administrator.

How do I schedule ERD creation? Command line syntax.

ERDisk Schedule Wizard allows you to schedule ERD creation. ERDisk will run and create ERDs for computers and at times specified by you in the Wizard. In order to access the network, Schedule Wizard sets the Windows NT scheduler service on the server to run under an administrator’s account. Scheduler service does not have to be run on any client computers to perform ERD creation.

How do I know if the process is completed successfully or with errors? Can I be notified about the results?

• ERDisk Log File provides a report on processes completed successfully and about any errors that might have occurred during ERD creation.

• Also, ERDisk keeps a record in the Windows NT application log.

• The upcoming version ERDisk 3.0 will have 'Journal' and 'Alerting' modules. The 'Journal' module will contain information about all processes scheduled and completed successfully or unsuccessfully. The 'Alerting' module will allow you to send reports and alerts by e-mail to specified persons.

• ERDisk returns a value of  0 or 1, depending on whether the procedure was a success or failure. If at least one process is completed with errors, it will return a value of 1. If you are using any third party Scheduler that uses program return values and notifies the user about the processes, then you can use it to send a notification message.

Log File. Troubleshooting.

Log File provides a report on processes completed successfully and about any errors that might have occurred during ERD creation. The numerical code in the log file represents the Windows NT error code. A description of the error can be found by using the following command: net helpmsg ErrorCode

For example, Error 67 means "The network name cannot be found." This error can occur if the computer for which you want to create ERD does not run "server" service or does not have ADMIN$ share.

The most typical problems include:

• The computer for which you want to create ERD does not run "server" service.
• The computer for which you want to create ERD does not have ADMIN$ share.
• You are using ERDisk with the Windows NT command line scheduler and your scheduler service is running under a local system account. Change startup information to run the service under the domain administrator account. Go to:  Control Panel--> Services -->Scheduler.
• Some of the errors might appear due to insufficient privileges for creating ERD, creating a directory or writing to the selected directory where ERD is saved.

Note: Demo version is restricted to creating ERDs for five computers at the same time. ERD will be created for the first five computers. You will get a NO_LICENSES error for the rest of the computers on the list.

ApplyERD

The standard procedure for restoring registry hives from ERD is time-consuming and requires three Windows NT startup disks, ERD (on a floppy disk) and CD-ROM with Windows NT original setup files. The process is even more complicated if ERD does not fit onto a floppy disk. In most cases, however, the computer which you need to recover is alive (can be booted and accessed from the network or locally). In this case, ApplyERD offers a painless 1-minute recovery procedure on a local or remote computer. Use this program to rollback changes in the registry hives to values stored when ERD was originally created.

ApplyERD is a separate application and is part of ERDisk distribution. ApplyERD provides an intelligent means of remote recovery, and solves any problem associated with ERD file size restrictions (1.44 Mb).

What do I do if ERD does not fit on a floppy disk?

The following situations are possible:

Windows NT is bootable:
-Use ApplyERD to restore appropriate registry hives.

Windows NT is unbootable but system files are on the FAT partition (or on an NTFS partition that can be accessed for write by using another Windows NT installation, or by temporarily connecting the disk to another system with Windows NT)
- Expand the appropriate registry hive from ERD. For example, to expand the SOFTWARE hive use:  expand Software._ Software
- Copy the expanded hive to the %SYSTEMROOT%\System32\Config

Windows NT is unbootable. The system partition is NTFS and is not accessible for write.
- Use Windows NT boot diskettes and any ERD which fits onto a floppy created on the same computer (for example,  ERD created when the server/workstation has just been installed), or from another computer with similar hardware and the same Windows NT version installed in the same directory. This should bring the server up (probably with all settings lost). See also How to Use Emergency Repair Disk To Restore Original System Settings
- Boot Windows NT and use ApplyERD to restore appropriate hives from the appropriate ERD directory. This will restore all settings and bring the computer back online.

Security issues?

ERDisk uses native Windows NT API for client-server authentication to create ERD or to schedule ERD creation.

Unlike some backup software products ERDisk does not require the installation of any services under the domain administrator account on client computers.   This minimizes the risk of having the domain administrator account misused or compromised. For greater security we recommend that you store ERD images on the NTFS partition of a physically secured server and set Full Control permission for System and Administrators Groups only for the directory with ERD images.

Is ERDisk Y2000-compliant?

Yes, it is. Year 2000 Compliance for ERDisk is based on 2000 Compliance for Microsoft Windows NT OS. Y2K is not compliant and will not be fully supported in Windows NT 3.51. However, it is already supported in Windows NT 4.0, and, according to Microsoft, will be supported in all future versions of MS Windows NT. Regardless of the Windows NT version, ERDisk will operate correctly after the year 2000 change. Program operation does not depend on absolute time. As far as timing is concerned, all process synchronization is based on relative timeout values that are supported properly on any version of MS Windows NT.

All date-time stamps in log files are currently in MM/DD/YYYY format. Therefore, the date after Y2K appears correctly in the log file if OS supports "long year" format. For example, '04/05/2005' is shown correctly on Windows NT 4.0. However, it appears as '04/05/0005' on Windows NT 3.51.

How do I use Emergency Repair Disk to restore original system settings

You can create a physical ERD upon demand by copying the files, including hidden and system files, to a floppy disk. Copy the subdirectory where you saved ERD for the computer you want to recover.
Note:  ERDisk creates by default a separate subdirectory %COMPUTERNAME% for each computer in the directory where you save ERDs. Copy the entire subdirectory to a floppy disk to create a physical ERD.

Use Emergency Repair Disk to restore original system settings:

Note:  Windows NT Setup disks and the installation CD are required.

1. With the computer turned off, insert Windows NT Setup Disk 1 into the floppy drive. Turn on the computer.
2. When prompted, insert Windows NT Setup Disk 2 into the floppy drive and press ENTER.
3. Select R to repair a damaged installation.
4. Select the options where a problem is suspected. Important: The original system configuration can be lost if you select Inspect A Registry File. Use it as the last option. Be careful when selecting Security and SAM Database during Inspect A Registry File process.
5. Follow the instructions using the arrow keys and press ENTER.
6. When prompted, insert Windows NT Setup Disk 3 into the floppy drive, press ENTER and follow the instructions.
7. Insert the Emergency Repair Disk into the floppy drive and press ENTER.
8. Depending on the options selected, press ENTER to repair the file or press ESC not to repair the file.
9. After the repair process is completed restart the computer.

Additional information is available in the following articles:

Article ID: Q129037
Windows NT 3.5x and 4.0 Emergency Repair Process Screens

Article ID: Q103280
Using an Emergency Repair Disk Created by Windows NT

Microsoft: Use NT Emergency Repair Disk to restore original system settings.

How is ERDisk licensed?

Licensing of ERDisk is based on the number of servers and/or workstations administered. An Optional Product Maintenance Plan is also available.