No need to feel intimidated around the Registry. Here's a brief tour -- and your chance to modify the Registry safely.

The Windows 2000 Registry

No need to feel intimidated around the Registry. Here's a brief tour -- and your chance to modify the Registry safely.

• By Harry Brelsford
• 03/01/2000

No, we're not talking about buying gifts for Spring weddings. This month's topic: the do-not-try-at-home, all warranties-are-void, don't-rip-the-tag-of-this-pillow-under- penalty-of-law Windows 2000 Registry! Are you tired of being pushed around by Microsoft and Win2K gurus when it comes to learning about the Registry? This month I'm going to build your confidence on the topic. By the end of the column, not only will you have defined and navigated through the Registry, you'll even have added your own Registry key.

What the Registry Is

Myths abound in the ranks of the high tech that the Registry is some evil monster lurking behind your colorful desktop, waiting to decertify you at the next mouse click. The Registry is simply an operating system database that contains configuration settings. For old timers, the Registry replaces the old *.ini files from the Windows 3.x days. Those of you with an OS/2 background will recognize the Registry concept. It's similar, leading me to ask if the Registry is one of the surviving offspring from that messy Microsoft/IBM divorce, which took place in the early '90s.

Specifically, the Registry stores:

• User profiles
• Application installation settings and document-type file associations
• Hardware profiles
• Port information

The Registry used a directory hierarchy before it became fashionable. Its basic tree structure -- with keys, subkeys, hive, and values -- hasn't changed since Window NT days. (Somewhere in here lurks a Win2K MCSE certification mindbender question, eh?)

Back It Up First! 

Before proceeding, it's critical to have a bona fide Registry backup. You never know when you'll need to roll back to a previous copy of the Registry. Needless to say, the Registry is taken seriously in Win2K. The developers have paid plenty of attention to Registry backup and recoverability. Not only does the built-in Win2K Backup program have the ability to back up the Registry, but so does every major third-party backup program on the market. In Win2K this happens when you back up System State data and create an Emergency Repair Disk (ERD). You may also back up the Registry by backing up the \%system_root%\repair folder (in English, that's typically C:\WINNT\Repair).

 The term "System State data" is new in Windows 2000. It refers to the following components:

• The Registry (found in both Windows 2000 Professional and Server).
• COM+ Class Registration database (this is developer stuff -- found in both Windows 2000 Professional and Server).
• Boot files (found in both Windows 2000 Professional and Server).
• Certificate Services database (part of Windows 2000 Server only).
• Active Directory (found in Windows 2000 Server only).
• SYSVOL directory (a shared directory that stores the server copy of the domain's public files, which are replicated among all domain controllers in the domain).
• Cluster service information (found in Windows 2000 Advanced Server, this software component controls all aspects of server cluster operations and manages the cluster database).

To back up the Registry as part of the System State data backup, follow these steps.

1. Click the Start button on the desktop.
2. Select Program | Accessories program group.
3. Launch Backup from the System Tools program group (found in the Accessories program group)
4. The Backup application appears as seen in Figure 1. Click the Backup Wizard button.

Figure 1. The Windows 2000 Backup application directs you in backing up the Registry, a first critical step.

5. The Backup Wizard launches. Click Next.
6. On the What to Back Up screen, select the "Only back up the System State data" radio button, as seen in Figure 2.

Figure 2. Selecting the System State data radio button will back up the Registry as well as other critical Windows 2000 files.

7. Click Next. The "Where to Store the Backup" screen appears. You would typically select your tape drive as the destination, but you can select another hard disk, Jaz drive, etc. Make your selection and click Next.
8. The Completing the Backup Wizard screen appears. Click Finish to start the backup.

Tip: When I performed these steps on a Dell PowerEdge 1300 server in my workshop, the System State data backup exceeded 305M -- which clearly won't fit on a single 3.5-inch floppy! Select your backup destination wisely.

9. You'll receive a backup complete notice similar to Figure 3.

Figure 3. The backup completion notice indicates the backup job has been completed.

Tip: You can also make Registry backup by exporting the Registry via the Registry Editor (discussed later in the column).

The Best Time to Work with the Registry, Typically

Whew! Now that you have a Registry backup (which, by the way, is the first step undertaken when you launch a significant support incident with Microsoft technical support), you can think about when you would actually need to perform surgery on the Registry. Such surgery certainly isn't performed when you install a well-behaved application. Both you and I look to the software developers to make Registry modifications in the background. But there are some software applications that aren't well behaved. For example, accounting applications installed on a Windows 2000 Server machine that uses the Btrieve database (instead of Microsoft SQL Server) require you to make entries to disable opportunistic locking (a subject beyond the scope of this column).

You're most likely to work with and learn about the Registry when you're on the phone with Microsoft technical support. Those technical wizards will have you perform feats of magic. You'll see Registry entries not documented in the MCSE certification courses nor Microsoft TechNet. In other words, you'll really learn the Registry when you have to.

You Already Modified the Registry

When you install Windows 2000 applications, you'll also modify the Registry. Modifying settings in Control Panel is another time you modify it. Adding new components such as hardware devices is a third way. In many cases the modifications are dynamic and don't require any further action on your part -- not even a reboot of your computer!

Building Confidence Under the Hood

Got that backup made? Now let's dabble. At the command line in Windows 2000 type:

regedit

This launches the Registry Editor. The result should look similar to Figure 4.

Figure 4. Meet the Registry Editor.

The Registry, as displayed in the Registry Editor, is comprised of the following HKEYs:

• HKEY_CLASSES_ROOT. Contains file association information.
• HKEY_CURRENT_USER. Contains profile information for the currently logged-on user.
• HKEY_LOCAL_MACHINE. This is the critical part of the Registry where you're likely to make modifications.
• HKEY_USERS. Contains profile information for all users created on the system.
• HKEY_CURRENT_CONFIG. This actually repeats some information presented in HKEY_LOCAL_MACHINE, such as the CurrentControlSet.

Without going too much deeper, the Registry is an advanced area of study. Now that you know how to get there, let's end with two fun exercises. First, you'll create a key in the Registry just to say you've done it! Then we'll finish by determining what settings are the current settings being used on your system.

To create a Registry key:

1. Type regedit at the command line to launch the Registry Editor.
2. Expand the HKEY_LOCAL_MACHINE folder in the left pane.
3. Expand the SYSTEM folder in the left pane.
4. Expand the CurrentControlSet folder in the left pane.
5. Expand the Services folder in the left pane.
6. Right-click on the Services folder in the left pane and select New | Key from the secondary menu.
7. Name the key "MicrosoftCertifiedProfessionalMagazine" and press Enter. Notice this new key appears at the bottom of the Services list in the left pane.
8. Highlight the MicrosoftCertifiedProfessionalMagazine key you just created.
9. Right click in the right pane.
10. Select New | String Value from the secondary menu.
11. Name the New Value #1 to read "Editor". Press Enter.
12. Double-click the Editor value to display the Edit String dialog box. In the Value data field type Linda Briggs. Click OK. Your screen should look similar to Figure 5.

Figure 5. You've now created a key in the Registry! Notice the key name of MicrosoftCertifiedProfessionalMagazine in the left pane and the string value Editor and data Linda Briggs in the right pane.

Tip: Notice that you didn't have to perform any type of file save in the above exercise for the changes to occur. That's because the Registry is dynamically updated.

Care to guess why you can complete the exercise without harming the Registry? Because you've created a Registry entry that isn't used by anything in Windows 2000.

I end the column this month with an under-the-hood look at how you can tell what source of information is being used by Windows 2000 to create the CurrentControlSet key (that is, what copy of the configurations is being used). Why show you this? Because when you work with Microsoft technical support, this is one item they'll have you check. Go to the following location:

HKEY_LOCAL_MACHINE\SYSTEM\Select

Figure 6. How to interpret configuration information in the Registry.

Now look in the left pane at the Current entry. What's the Data value? As you can see in Figure 6, it's "1". That means the configuration information stored in the ControlSet001 key is being used as the CurrentControlSet by Windows 2000. Had enough? Good! See you next month.