You can choose from several methods to back up your registry, and you can store your backed-up version on a variety of media. Whether you use the Windows XP Backup program or similar utilities, DOS commands, or the Registry Editor, you should first understand what type of file systems your computer network uses. Windows XP supports two different file systems. The first file system, called FAT (File Allocation Table), is identical to the file system used with both DOS and Windows 95/98/Me. The FAT file system is not secure and offers no resistance to hackers and others who want to access files improperly. There are several flavors of the FAT file system: FAT12, FAT16, and FAT32. Windows XP fully supports FAT32 and FAT16. This support allows compatibility with Windows 98's large disk support. Note Windows NT 4 does not support FAT32 except in a very limited, read-only manner. You cannot install Windows NT 4 onto a FAT32 drive. FAT12 is antiquated and is unlikely to be found on Windows NT systems. The second file system, NTFS (NT File System), is unique to Windows XP. Though it is possible to read an NTFS drive from DOS or Windows 95 using shareware utilities, it is generally not possible to write to an NTFS drive unless you are using Windows XP. However, System Internals (see their Internet site at www.sysinternals.com) has two utilities that allow you to write to an NTFS volume from DOS or Windows 95/98/Me.

Backup Utility Backing Up to Tape or Other Media

The Windows XP backup program, Backup (NTBackup.exe), is one of a whole slew of compatible backup programs that allow backing up the system registry to tape, diskettes, other hard drives, CD-R, CD-RW, or for that matter, any other Windows XP–supported writeable media. The process is straightforward and can be done as part of a regular backup cycle, or whenever desired. Just check System State in the backup tree to back up using Backup or use the Automated System Recovery Wizard on Backup's Welcome tab.

With ASR selected, the wizard creates three backup sets:

• A full backup of the system drive. This backup contains everything that is on the drive. These files are backed up prior to Backup saving the registry to the %SystemRoot%\Repair folder.

• A backup of the %SystemRoot%\Repair folder, after Backup has removed the original backed-up registry components. The only two files contained in this folder are asr.sif and asrpnp.sif.

• A copy of the System State. When Backup stores the System State, it saves the following three items: o Boot files: the files used to boot Windows XP o COM+ Class Registration database: the COM+ classes' registration o Registry: the set of files that comprise the configuration of Windows XP Note In Windows 2000, to create an ERD, you use the Backup program. In the Tools menu, simply select Create an Emergency Repair Disk. Backup will prompt for diskettes as needed. Windows XP does not allow separate creation of the ASR disk. Using Backup is simple if you are familiar with creating and restoring tape backups. However, you may encounter a few difficulties in using backups of the registry. First, to keep the System State backup easily accessible, it would be wise to place the System State backup on its own media. If the media is inexpensive, this is a viable practice, but if you are paying an arm and a leg for media, this can be costly. Each System State backup includes a full disk backup as part of the backup process. Second, System State and registry backups must be kept secure, perhaps more secure than standard backups. Everyone's situation is different; just realize that unrestricted access to the registry allows unrestricted, unaudited access to everything else as well. Hacking a backup copy of the registry can reveal information that might seriously compromise your system's security! Finally, tape backups are sometimes slow. Stick the tape in the drive and the first thing that happens is that the tape gets rewound (to re-tension it). This process alone can take some time time that is not available when you are working on getting a server up and running. Consider instead backing up the registry to a local hard drive (a drive other than the system drive, however). Backups to networked drives should be approached with caution: unless running a fast network, such a backup might seriously compromise the network performance for an extended period of time. As an example, on a 10BaseT network, backing up 1GB of data would take over 16 minutes!

Backing Up Using copy or xcopy

It is not possible to copy back the current registry while Windows XP is using the registry. Period. Therefore, to restore the registry using either copy or xcopy, it is necessary to shut down Windows XP and start another operating system, such as DOS, Windows 95/98/Me, or a second copy of Windows XP. Which operating system you use depends on which file system is being used on the computer. If the file system is FAT, you should start DOS or Windows 95/98/Me. If the file system is NTFS, you should start a second copy of Windows XP. Note Microsoft recommends that Windows XP be installed on NTFS partitions. This recommendation is for both performance and security reasons. You can install multiple copies of Windows XP on the same computer, and these installations do not have to be the same "type" (Server and Workstation). As long as the operating system installed has a user with sufficient privilege, you can access files (including the registry) from any of the Windows XP installations. Backing up the registry with copy or xcopy is easier than using Backup: 1. Run the Backup program and create an ASR disk (if you do not have a current ASR disk). 2. Copy the backup of the registry found in the %SystemRoot%\Repair directory to another location. 3. Then (this step is optional, but can't hurt), xcopy the current registry files in the %SystemRoot%\System32\Config directory. Use the /c option to tell xcopy to ignore errors. (This is necessary because the current registry is in use. The xcopy command cannot copy files that are open and will generate an error without the /c option.)

Backing Up If You're Using FAT

Those Windows XP users who are using the FAT file system can simply boot a DOS, or Windows 95/98/Me (if FAT32 is used), diskette formatted with the /sys option. This will give you a DOS command prompt allowing you to read from and write to the hard drive quite easily (of course, accessing output media requires DOS or Windows 95/98/Me support). To create a bootable FAT-compatible disk, simply use the Windows 95/98/Me or DOS FORMAT command with the /s system option. Then copy xcopy's files (xcopy*.*) to the diskette, too. This disk may then be booted in the Windows XP computer, allowing unrestricted accesses to all FAT-formatted drives installed on the computer. When using Zip, CD-R, or CD-RW drives, it may be necessary to add DOS drivers for these drives to your boot diskette. Note If the system is already configured for dual-booting, you probably can use the second operating system instead of using a boot diskette. It probably won't matter which alternate operating system is installed (DOS, Windows 95/98/Me, or even variations of Windows NT); all will work fine for the purpose of backing up the registry. There is no need for boot diskettes in this situation. After booting into a command prompt, it is a simple task to copy the registry files to a safe location, such as another hard drive, a set of diskettes (the registry won't fit on a single diskette), a Zip drive, a CD-R/CD-RW drive, or other supported media. Note Some computers allow booting from the CD-ROM drive. If this is the case for your computer, then it is also possible, if you have a CD-R/CD-RW drive, to create a bootable CD.

Backing Up If You're Using NTFS

Users with NTFS are presented with a much more difficult problem. The NTFS file system is a secure file system that may not be easily accessed using other operating systems not compatible with NTFS, such as DOS or Windows 95/98/Me. Files on an NTFS drive may only be written by Windows XP and not by other operating systems. Sure, some utilities allow NTFS to be accessed from Windows 95/98/Me. However, the mode of access is typically read-only; there is no chance of a restore that way. Some utilities or drivers do offer write access to NTFS file systems, however I don't recommend using them except as a last resort, because they may not be compatible with future versions of NTFS. To be able to access the registry files on an NTFS drive, you must install a second copy of Windows XP. Tip Actually, everyone should have at least two installations of Windows XP: the working copy and an emergency installation to use if the working copy of Windows XP is unable to boot. Windows XP supports multiple boot configurations quite effectively. To create a multiple boot installation of Windows XP, simply follow these steps:

1. Ensure that you have sufficient space on your hard drive for a second copy of Windows XP. Your second copy of Windows XP only needs to be the basic operating system only a minimal amount of hard disk space is required. Figure 200MB to 1GB of hard disk space for this backup installation, depending on how much additional software and features you install. (Some users want two virtually identical installations, though this type of installation may consume substantially more disk space than a minimal installation of Windows XP.)

2. Using the Windows XP installation boot diskettes, begin your installation. When prompted for a destination, simply specify a new, different directory than the working installation of Windows XP. If you are farsighted enough, and are doing this before disaster has struck, you can install directly from the distribution CD without using the boot diskettes. To do so, run the Windows XP Setup program to begin the installation process. (You can also install directly from the distribution CD if the hardware supports a boot from the CD drive.) Warning Don't install to the same directory that your current working installation of Windows XP is installed into. That won't create a second copy of Windows XP.

3. The Windows XP Setup program will configure the Boot Manager (creating new entries in the boot menu) so that you are able to choose which copy of Windows XP you want to boot.