Why You Should Know About Disks

Disk problems are frequently the cause of startup failures. Some of these problems are the result of hardware errors. But frequently the problem is that Windows NT is unable to find the information about the disk or its contents, usually because of control information corruption. If you know what the control information on your disk should be, you can tell if it has been corrupted.

There are several reasons that Windows NT cannot give your computer complete protection:

• The security provided by Windows NT is effective only when the operating system is running. If you are running another operating system, or if an unauthorized person can walk up to the computer and restart it, Windows NT cannot provide any protection.
• External media devices, such as floppy disks and CD-ROMs, provide the physical means for anyone to bypass Windows NT and gain access to your files. You can also introduce viruses from floppy disks or from files that you copy or download from other computers.
• The transaction logging that the Windows NT file system (NTFS) does for recoverability purposes protects only NTFS metadata.
• A power failure can cause corruption. So can turning off your computer without going through shutdown.

This following list highlights simple procedures that you can implement to reduce the potential for problems and make it easier for you to recover when problems occur.

• First, implement physical security. Put your computers in a secure room. Lock them. Use a password on your screen saver. Run virus checks on your computer and on floppy disks before you use them. Or disable the floppy disk, which is supported in some system BIOSs. If you cannot disable the floppy disk in the BIOS, you can physically disconnect it.
• Develop a preventive maintenance plan and schedule regular maintenance. You might not know about file system problems until you restart your computer, when the Chkdsk program tells you that there are errors or that a volume is Unknown.
• Back up data that are critical to the operation of the computer when you make changes to them. These data include the Registry, Master Boot Record, and Partition Boot Sectors. You also need a way to start another installation of Windows NT Server if the one you normally use doesn't work, either because hardware failure or corruption makes the primary installation unusable.
• Know the configuration of the computer. If you have more than one disk with more than one partition, you need to know which data are on which partitions on which disks. For example, which partition is your system partition or your boot partition? If you have implemented volume sets, stripe sets, mirror sets, or stripe sets with parity, which disks are members of which sets?
• Implement a backup procedure for user data. Users will delete files or make changes to them and then want the old version back. Files can get corrupted when applications crash. A power failure can adversely affect files and disks in many ways. You need to be able to restore individual files, as well as a complete disk's worth of data, or even all of the files on the computer.

This chapter, and the other chapters in the "Reliability and Recoverability" part of this book, provide much more detailed information about the preceding topics. There are more details about disk organization, file systems, and starting your computer in the following chapters of the Windows NT Workstation Resource Guide:

• Chapter 17, "Disk and File System Basics."
• Chapter 18, "Choosing a File System."
• Chapter 19, "What Happens When You Start Your Computer."