BACKUP AND RECOVERY,Backups And Fault Tolerance,Understanding Disk Data Recovery,Looking At Backup Hardware,Reviewing Tape Drives

Backups And Fault Tolerance

Windows 9x and Windows NT both offer tools that allow you to make backups of data and software from a hard drive. Backing up your information is important to guard against unexpected disk or computer failures. Another feature of preventive maintenance is to make hard drives more fault tolerant, which is the ability of a computer to respond to a fault or catastrophic event, such as a hardware failure or power outage, in such a way that data is not lost. Several methods to do this are collectively called RAID. The term stands for redundant array of independent disks. We’ll take a look at several methods of RAID.

Understanding Disk Data Recovery

DOS and Windows 9x offer the tools to manage the data on a disk, and DOS can recover lost data if the disk is not too badly damaged. Utility software can sometimes read a disk that is too damaged for the operating system to read, because the software does not use the operating system or System BIOS to read and write to the disk.

When trying to recover data from a disk, if possible, make a backup of the disk first. Keep a separate, second copy of important data on more than one disk. Disks of different sizes and densities format data much the same way. All disks have a boot record, file allocation table, and root directory.

Looking At Backup Hardware

Removable drives, such as tape drives, Zip drives, Jaz drives, and read-write CD drives, can be used to back up a hard drive. These devices are commonly used on stand-alone personal computers and small servers. However, in a business environment, the most practical backup method for PCs connected to a file server is to back up the data on the PC’s hard drive to the file server. If the software becomes corrupted, it can quickly be reinstalled from the installation files kept on the file server. Data on both the PC and the file server may become corrupted. However, the file server will most likely have its own automated backup utility in place that backs up to either tape or a larger mainframe computer.

Reviewing Tape Drives

A tape drive, as seen in the following figure, is an inexpensive way to back up an entire hard drive or portions of it. Advantages of using tape drives include:

Convenience over floppy disks or other types of removable disks Relatively inexpensive Tape drives have drive capacities that vary from several hundred kilobytes to several gigabytes and come in several types and formats. Although tape drives don’t require special software, you may want to invest in backup software to make backups as efficient and effortless as possible. One disadvantage of using tape drives is sequential access. Sequential access does not allow you to fast forward or go directly to the location of data on tape. Instead, you must start at the beginning of the tape and read through it until the sought-after data is located. This process makes it slow and inconvenient to use tapes for general purpose storage of data (other than backups) and to recover individual files from full tapes.