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ERD Commander Wins 5 Palm Award from Beverly Hills Software!
Copyright © 1998 Mark Russinovich and Bryce Cogswell
Last Updated March 11, 1998

ERD Commander V1.0 Read-only
Introduction When problems arise in Windows 3.1 or Windows 95 that render a system unbootable, there is always the possibility of booting off of a DOS floppy disk so that the drives of the machine can be accessed for repair and salvage. This boot-floppy approach to system recovery is often the only way to correct problems that even "automatic" system repair utilities fail to correct. In the past, Windows NT administrators have gone without this recovery option. ERD Commander finally brings boot-floppy functionality to Windows NT.

ERD Commander is a utility that enables you to boot NT off of a floppy disk in order to access and repair a dead NT installation. It is a command-line shell that runs off of a set of NT boot disks giving you full access to non-bootable NT systems with a robust set of familiar command-line file manipulation tools including copy, rename, delete, move and xcopy. Because ERD Commander relies on a standard set of NT boot floppies, any NT system is accessible, and because ERD Commander runs on top of NT, all NT file systems, including FAT, NTFS, and CDFS are visible. Note that ERD Commander has no reliance on data located on a system's hard disk for it to boot and run - NT is actually booted on the floppies. Thus, NT does not even have to present on the computer in order to use ERD Commander to access the computer's drives, assuming that they are FAT or NTFS.

ERD Commander works on NT 4.0 only.

This read-only version introduces you to the capabilities of ERD Commander. Most commands that cause modifications, such as delete, rename, move, etc., are documented here, but are disabled. Mkdir and Rmdir are the two modification commands enabled in this version. Information on ordering the read/write version of ERD Commander is available at Winternals Software.
Uses The full read/write version of ERD Commander can be used to help you solve problems such as:

Removing or Replacing Buggy Drivers
You can use ERD Commander to delete the image files of drivers or services that, because of a bug or misconfiguration, prevent NT from booting.

Updating Out-of-Date System Files
Incorrectly applying service packs or system software updates can cause system DLLs to become out of sync with each other. In many cases this can prevent NT from booting successfully. ERD Commander can copy up-to-date versions of old files from floppy disks or CD-ROMs onto a system.

Correcting Misconfigured NTFS Security
If security attributes that are too restrictive are applied to certain system files or directories on NTFS boot drives, NT will become unbootable. ERD Commander includes a special command, Access, which unlocks otherwise inaccessible files or directories so that NT can access them.

Updating Locked Files
Once NT is up-and-running many system files cannot be replaced because the system keeps them locked. ERD Commander makes it possible to update such files because it runs when NT is off-line and the files are not open.

Correcting Registry Problems
A number of NT boot problems are the result of misconfigured Registry values. With ERD Commander you can copy Registry hives (located under <winnt>\system32\config) off the system to a floppy disk or other writeable removable media for modification on another NT machine (using Regedt32's Hive loading capability). Modified hives can then be copied back.

Copying Important Files off of a Dead System
ERD Commander enables you to access files on an NT system that fails to boot. Important files can be salvaged onto a floppy disk or other removable media.

Note that ERD Commander is not intended to resolve disk corruption errors, and that only drives that are consistent enough to be recognized by Windows NT file systems will be accessible with ERD Commander.
What it Looks Like Below is a presentation of what a typical display looks like after ERD Commander has started. ERD Commander shows information on the disk drives that are recognized and the drive letters it has assigned for them. Volume name, file system type, and drive size data should help you identify particular drives.

         ERD Commander screenshot
Installation When you execute the ERD Commander Setup program it will allow you to create a set of Windows NT boot floppies configured with ERD Commander. Optionally, you can supply an existing set of floppies to be configured.

The Setup program will install two versions of the boot floppy creator onto your hard drive. The 32-bit version is the program that is run during the initial Setup. The 16-bit program allows you to configure boot floppies with ERD Commander from a DOS boot floppy or from Windows 3.1. This is necessary in cases where your Windows NT installation is non-bootable and you do not have access to a second NT machine or to Windows 95.

After the disks are loaded, a stripped-down version of Windows NT will start, displaying the familiar boot-time Blue Screen that presents the NT version number, system memory size, and number of processors present. ERD Commander then starts automatically and enters a command-line environment nearly identical to the one NT implements in Command-Prompt.
Command Set The command set of ERD Commander, like its command-line editing features, is similar to that of NT. The command set includes all standard file-related commands, and virtually all support the same options as their NT counter-parts. This list can be obtained inside of ERD Commander by entering the HELP command, and detailed information on the syntax of a particular command can listed by typing "command /?" or "HELP command". Note that the commands are interpreted in a case-insensitive manner so that "HELP" is the same as "help".

Commands colored red are disabled in the read-only version of ERD Commander.
ACCESS Gives Everyone full access to a files or directories.
CD Displays the name of or changes the current directory.
CLS Clears the screen.
COPY Copies one or more files to another location.
DEL Deletes one or more files.
DIR Displays a list of files and subdirectories in a directory.
EXIT Quits ERD Commander and reboots the system.
HELP Provides Help information for ERD Commander commands.
MAP Displays drive letter to partition mapping.
MKDIR Creates a directory.
MOVE Moves one or more files from one directory to another directory.
RENAME Renames a file or files.
RMDIR Removes a directory.
XCOPY Copies files and directory trees.
VER Displays ERD Commander version number.
Download ERD Commander (780KB self-extracting .exe)