Boot to an NT command line from a floppy disk

Troubleshooting a corrupted OS is a lot easier if you can boot from a floppy disk. MS-DOS and Windows 9x give you this ability, but Windows NT's kernel is simply too large to fit on a 1.44MB disk. Therefore, using a disk to boot to an NT command line is difficult, if not impossible. In addition, NT lacks a command-line-driven kernel. The NT boot disks contain a microkernel that lets you perform only limited functions.

In some corrupted-OS and blue-screen disasters, a standard NT Emergency Repair Disk (ERD) helps you restore Registry and system files—as long as you keep your ERD up-to-date. But what do you try when the ERD doesn't solve the problem, the NT setup repair feature fails, and the last known configuration still gives you a blue screen? A parallel installation? A full setup and restore from tape? Maybe you need Winternals Software's ERD Commander Pro 1.06.

ERD Commander Pro modifies a set of existing NT setup disks or creates a new set from the original NT CD-ROM. You then use these disks to boot to a powerful NT 4.0 command-line mode for troubleshooting purposes. ERD Commander Pro 1.06 works with NT 4.0 and 3.51 workstations and servers. (A new version, ERD Commander Pro 1.2, adds support for Windows 2000.)

Install and Boot
I tested ERD Commander Pro on a Dell OptiPlex Pentium II workstation running NT Workstation 4.0 Service Pack 5 (SP5). The ERD Commander Pro software, which comes on one disk, placed a small setup program on my hard disk during installation. When I ran the setup program, it asked me for the original NT CD-ROM. At this point, I could instruct the setup program to create new NT setup disks or use my existing NT setup disks. I chose to create new disks. The setup program then modified setup disks 1 and 2 and created a fourth disk with some added utilities (including Chkdsk). The program didn't ask for disk 3. The whole process, including disk modification, took about 10 minutes. The setup program then informed me that I could reboot to disk 1 and use the ERD Commander Pro command line.

The reboot was initially confusing. My system needed to read the contents of the three modified NT setup disks (not just disk 1) into memory. Thus, getting to the ERD Commander Pro command prompt took a couple minutes. Also, when I booted from the first disk, I saw what appeared to be the standard NT Setup program. I thought that the ERD Commander Pro setup program might have incorrectly modified my setup disks until the NT setup routine asked for disk 2 again right after reading disk 3 (the standard NT Setup program asks for the NT CD-ROM at this point). After the setup program reread disk 2, the command-line environment appeared.

A quick note on using ERD Commander Pro with newer servers. Some server manufacturers such as Dell use newer Adaptec 78xx Ultra SCSI chipsets that aren't included on the boot disks or the NT Server CD-ROM. The Winternals documentation explains how to modify the txtsetup.sif on disk 1 to include entries for the appropriate drivers. You then must physically copy the SCSI driver .sys files to disk 3. Any server with nonstandard (or newer) SCSI cards won't work with ERD Commander Pro unless you make these changes. You'll know you must complete these steps if you type MAP and notice that none of your hard drives is mounted.

Using ERD Commander Pro's Tools
As Figure 1 shows, ERD Commander Pro's command-line environment lists the local drive letters and their associated devices above the command prompt. ERD Commander Pro includes all the directory- and file-modification tools (RD, MD, CD, Copy, Dir, Move, XCopy), and they work as you would expect, even on NTFS volumes. The utility's advanced tools are particularly impressive. The Password tool changes account passwords (including the administrator password); the Service tool stops, starts, and disables NT services; the Access utility gives anyone full access to an object; FTDisk lets you manipulate a fault-tolerant disk set; Expand lets you expand files from a CD-ROM to your hard drive; and Attrib is the familiar DOS command.

Most of the advanced commands require ERD Commander Pro to connect to an NT Registry on a local partition. You specify the directory that contains the Registry you want to modify; therefore, multiple NT installations aren't problematic. I entered the Registry command to connect to the NT Registry on my C drive, then performed several useful troubleshooting tasks, including copying hive files to a floppy disk. Chkdsk ran smoothly on my local disks. I used the Password command to change the password on the administrator account. (I didn't need to know the original administrator password to make this change.) I used the Service command to start and disable the spooler service. If a particular service is causing a blue screen, you can use Service to disable it.

Clearly, ERD Commander Pro is a powerful tool—and, in the wrong hands, a dangerous one. It lets the user read and change files on the system and on other disk volumes, copy the Registry to an offline resource, and change passwords. If you purchase this utility, be sure to keep close track of the original ERD Commander Pro disk, the installed ERD Commander Pro setup program, and the created or modified NT setup disks.

Also, remember that step one in computer security is physical security. Lock up your computers at night. To protect systems from utilities such as ERD Commander Pro, remove floppy disk drives or use the BIOS settings to disable the floppy disk boot option.

A Smart Buy
At $324, ERD Commander Pro is a smart buy. The license agreement lets you create one set of modified NT setup disks that you can use on any number of NT systems. The more I worked with the various commands, the more I understood the utility's usefulness. The Password and Service commands alone are worth the purchase price. The command-line environment is powerful and easy to use. However, the online Help's description of what happens at boot time is vague.

When was the last time you updated your ERD? More important, when did you last try using it while your CIO watched over your shoulder? An NT administrator can never have enough disaster-recovery tools. Although ERD Commander Pro won't guarantee a recovery every time, the tool is bound to come in handy.

ERD Commander Pro 1.06
Contact: Winternals Software * 800-408-8415
Web: http://www.winternals.com/
Price: $324
Decision Summary
Pros: Lets you boot to an NT command prompt from a floppy disk and offers impressive command-line functionality, including password cracking and service manipulation
Cons: Takes a few minutes to reach the ERD Commander Pro command prompt when booting from the program-created disks; powerful command-line features pose security risks; you might need to modify the created disks to support newer servers' SCSI cards