Back-up Wars: Attack of the Clones

One solution that makes backing up easier and more complete is cloning. This creates an identical copy of your hard drive at a particular time.

This copy, which is stored in a single file called an image file or disk image, can be placed on a separate disk partition, a different drive or on removeable storage media.

With an image file, you can easily restore a damaged system, move your current system to a new hard drive, or (if you're an IT manager) save time setting up new machines by reproducing the system on multiple PCs.

Although software for disk cloning, also known as drive imaging, resembles data backup software, there's a major difference: cloning operates at the disk or partition level, not the file level.

Cloning software is designed to produce a static image of the system, although recent products, such as Drive Image 4.0 and Norton Ghost 2001, let you add data to existing image files.

In fact, Symantec's Ghost products now allow automatic incremental creation of image files, which is a useful feature for IT managers in charge of several machines on a network. For maximum safety, and for exact copies of your drives or partitions, create a disk image and leave it unchanged.

This lets you restore your PC to precisely the condition it was in at the time of image capture. The image file created by the cloning software contains all details of the hard drive or partition you're cloning and includes all files, no matter what their attribute settings.

For example, the image will hold all hidden and system files, including the crucial IO.SYS and MSDOS.SYS (essential for booting Windows 9x), the NT data files required for a dual-boot system (Windows 9x with NT and 2000) and the master boot record itself.

Because everything about your disk partitions, operating system, applications, utilities and configuration settings are simple data bytes, and because the image file captures the original on a byte-by-byte basis, the completed image file contains everything needed to reproduce exactly the hard drive or partition.

Of course, many users have only one partition on their hard drives, so the size of the image file is a concern. Cloning packages solve this problem by copying only those hard drive sectors that contain data. In addition, the software will offer to compress the data for you.

PowerQuest's Drive Image products, for example, let you specify compression ranging from none to approximately 50 per cent.

Together, these techniques can result in an image file substantially smaller than the original partition, allowing you to store your image files on a second hard drive, CD-R or CD-RW. Drive Image and Ghost support direct saves to a writable CDRom drive.

Hard drive restoration

Cloning software is probably most useful when recovering from a hard drive failure. If the primary drive containing the boot partition becomes unusable, the value of an exact snapshot of the system is obvious: you can restore the PC to a workable state. For secondary drives, which often contain important data, the snapshot can be equally valuable.

On installation, cloning packages let you create a start up (boot) floppy disk. To recover the hard drive's contents, boot the PC from the startup disk and the resulting DOS prompt, launch the package and use its restore utility to open the image file and reconstruct your files and configurations.

The package's wizard will guide you through the process, which consists of selecting the hard drive and partition on which to effect the restore. For such a process to be truly useful, your disk image needs to be fairly recent.

Rolling back your system

A more common, and less dramatic, purpose for using cloning software is to capture the state of your system at a particular moment. By creating and storing image files from specific times, you can roll back your system to the moment the image file was created.

Although you can use this technique for back up, its primary function is to let you restore your system to a previous state in the event of performance problems or malfunctions caused by new software or hardware installations.

Some hardware/software combinations don't function well on certain PCs or with some operating systems. At such times, often the easiest solution is to cut your losses and roll back the system to a point where it worked properly. However, make sure you back up any files you want to keep before performing the recovery.

Buy more space

As the cost per megabyte of hard drive storage drops, and the number of available operating systems and applications rises, replacing your existing hard drives with larger ones makes sense.

However, installing a new 40Gb drive takes time and effort if you want to keep your existing configuration and data. This is especially true if it will replace your boot drive.

You could use dedicated backup software but, in most cases, restoring your files to the new hard drive requires that Windows be installed on the new drive first. What you want is the ability to transfer your entire system from one disk to the other, then retire your original disk or use it for back ups.

To replace your primary hard drive with a larger one, use your cloning software to create an image of your current primary disk on a CDRom or other removeable media type, then remove that hard drive and install the new one.

Using the start up floppy disks your cloning software creates during installation, boot your PC - you'll be in DOS mode - and use the restore feature to locate your disk image and transfer it to your new hard drive.

When you boot from your new disk, the system should appear exactly as before except for the additional capacity. Note that the old disk you removed still has all your original files, so it can also serve as a back up.

Manufacturers of disk cloning utilities warn that their products don't support disk image transfers from one PC to another. The hardware and configuration settings in the old PC's Windows Registry and files won't match the new one, which could cause problems. Also, any software preloaded on the new PC would be deleted.

You can still try transferring a disk image, if you're careful. Install the cloning software on both systems and make disk images of both. Boot the new PC from its start up floppy disks and restore the old one's disk image on the new system.

Try starting the new PC. If it boots, launch System Properties from Control Panel, delete any questionable hardware entries in the Device Manager dialog, then run the Add New Hardware applet from Control Panel. If it works, you've transferred your disk. If not, restore the image from the new PC's start up disk.

Transferring image files to new PCs works well for organisations that purchase identical machines. In fact, the corporate versions of Drive Image and Ghost allow administrators to remotely transfer image files to network clients. This standardises the configuration and applications across the organisation's workstations.

Other considerations

Disk cloning can save you hours of frustration, but you can also experiment with the software before anything bad happens. Start by cloning a small partition from one of your hard drives (or creating one expressly for this purpose), then wiping it out and restoring it from the disk image.

Next, clone multiple partitions and try restoring those. Once you're confident that the software works, back up your system using a back up package, clone the entire disk and wipe out all data on your hard drive.

Next, restore the system to its working state. If you familiarise yourself with this, you'll be more confident when you encounter a true disk emergency.

The Windows 2000 problem

Although disk imaging can cause problems, Microsoft has supported imaging as a viable method for system deployment. This is especially true for Windows 98 and ME, because these operating systems support plug-and-play device recognition, which eases many hardware incompatibility problems.

Windows 2000 also supports plug-and-play, but Microsoft has been less than forthcoming with its cloning support for this because the NTFS file system requires certain security measures that might interfere with cloning. Windows 2000 runs most effectively on NTFS and Microsoft doesn't want to compromise security.

The primary difficulty with cloning Windows 2000 systems is that the operating system creates security identifiers (SIDs) during installation.

Each workstation and user account on the network has its own SID. Every interaction with system security, including all disk activity on an NTFS system, requires SIDs.

The problem with cloning Windows 2000 systems (and NT) is the possibility of duplicating the SIDs themselves. If the SID is copied along with the drive image, two systems could have identical SIDs as well as the same permissions.

This problem occurs primarily on networks configured as NT/2000 workgroups, not those set up on a domain through a Windows 2000 Server platform. This is because the domain software controls the SIDs for the workstations and their users. Each time a user logs on to a domain, its server issues an SID to prevent duplications.

Microsoft offers a System Preparation Tool (SysPrep) to help solve this problem. You can download the tool here or install it from your Windows 2000 CDRoms.

SysPrep modifies the SIDs on each system where the image is copied, thereby allowing the clone to proceed. The latest versions of Ghost Enterprise Edition and Drive Image Pro work with SysPrep to ensure that security problems are solved.

You install and run SysPrep first, then create the disk image. When you restore the image to a new PC, the new workstation identifier is in place and transferred user accounts use this SID in conjunction with their unique account SIDs to ensure security.

THE ART OF CLONING

1. Install disk cloning software on your Windows PC, then launch the software (it'll reboot in DOS mode).

2. Using the software's wizard, clone the hard drive you'll be removing onto a second hard drive or a set of writable disks.

3. Turn off your computer, unplug it and remove the cover of the case.

4. Carefully unplug the power wires and data cable from the hard drive you're taking out. Undo any fasteners and remove the drive.

5. Check that your new drive's jumpers are properly set to make it the master or slave IDE device, whichever the removed drive was.

6. With the jumpers set, attach the mounting hardware to the new drive, plug in the power wires and data cable, install the drive in a vacant bay, close the case and plug in the power cord.

7. Insert the boot disk created by the software into the floppy disk drive and turn the PC on. When DOS is booted, launch the cloning software.

8. Follow the software's directions to copy the cloned data from the backup hard drive or CDs onto the new hard drive. When you're finished, exit the program and shut down your PC.

9. Remove the boot disk from the floppy disk drive, start your PC and enjoy your new hard drive.

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