Sarasota PC Monitor
Tech Talk(12/99)
Back Up Strategy
by Brian K. Lewis, Ph.D.*
Member of the Sarasota Personal Computer Users Group, Inc.As hard drives keep getting larger, and cheaper, more questions keep arising as to the best method of backing up the drive's contents. For years users have relied on tape drives for backup. However, tape drives are very slow and backup frequently seems to take forever. Especially when you include time for verification. Restoring a single file or a folder from a tape is also a time consuming process. Tapes have other problems, so the net result is that the hard drive is generally not backed up frequently enough. However, it should be noted that large networks do successfully use tape drives for backup. The drives they use are not the low-end models sold for the small office/home office (SOHO) market. They are usually digital units that are faster and much more expensive.
There are other methods of backing up, including using removable drives and writeable CD's. However, when the standard hard drive being sold with a new computer is 8-9?gigabytes and the largest removable drive is 2 gigabytes, there is a problem. No one likes to sit by their machine and swap disks as they are filled up. So in many cases, only the data files are backed up, not the applications. Of course, it's the applications that take the major amount of space on the hard disk. The theory is that since you have the original program disks, should anything happen to your drive you can restore the program easily. In practice, this frequently fails, because you have downloaded patches and program updates from the Internet. If you don't have backup copies of these downloads, you have to go hunting for them again and hope they haven't been removed from the web site. The problem is even worse if you use CD's for backup. They are certainly much cheaper than removable hard disks, but they also hold only 640 megabytes. So I use CD's only to store the large files I have downloaded from the Internet. You can do the same thing by using Zip disks or LS-120 disks. But you should certainly store any downloaded files on some media other than your hard drive.
There are some who believe that writeable or re-writeable DVD will solve the problem of backing up large hard disks. However, the format for these disks has not been standardized. DVD writers are not yet available in quantity or at price that would make them competitive with other backup media. Additionally, the capacity of the DVD media appears to be about 5 gigabytes. Certainly that is larger than other removable drives, but by the time it is readily available, hard drives will be pushing 20 gigabytes in size. So DVD may become an alternate storage media for photos, videos and music files. All of these require considerable space.
Another alternative is to use a second hard drive for backup purposes. In larger business networks, a RAID setup may be used. The term, RAID, means a Redundant Array of Inexpensive Disks. These are frequently a series of SCSI drives connected to a controller card in a network server. The card controls the reading and writing to the individual drives. Some motherboard manufacturers are now incorporating RAID controllers into the motherboard itself. These are still generally SCSI controllers designed to handle a multi-drive array.
As the prices for the larger drives being sold for the desktop market continue to drop some manufacturers are preparing less expensive RAID solutions using single IDE drives. There are RAID controller cards available that can be added to a system to automatically copy everything on the main drive to a secondary drive (mirroring). However, single drive mirroring has problems that don't occur in larger RAID systems. For example, if a file is corrupted on the main drive, this error may be instantly and automatically, copied to the second drive by the mirroring system. Then, the next time you access the file you receive an error. Attempting to restore the file from the backup will also result in an error. The single drive RAID system would seem to be more suited for replacing a drive when there is a catastrophic failure. I doubt that it would be suitable for solving file corruption problems.
With the decreased cost of hard drives, it is possible to consider a system that uses more than one hard drive for backup. There are "drive carriers" available that plug into a receptacle installed in a 5?" drive slot in your computer. These carriers can be removed and stored in a separate location from your system. They can also be used in a system where you have two or more backup drives used on an alternating basis. This would not work with RAID hardware, but would work with disk imaging software or regular backup software.
The previous discussion relates primarily to failure of the software or data on a hard drive. This can result from failure of individual sectors on your drive. Your backup strategy should also take into account the possible mechanical or electronic failure of a hard drive. In some two-drive systems, the user hopes to be able to make the second drive bootable, so if the first drive fails, a swap can be made. Getting a second drive to be reliably bootable and working as a reliable backup is very difficult in a Windows environment. If the system uses two IDE drives, then when the first fails, you have to open the case and change the jumpers on both drives to make the backup drive bootable. However, if one drive is IDE and the other is a SCSI drive, then you only need to make a change in the BIOS setup to change the boot drive. You can then wait until later to open the case and remove the failed drive.
The generally recommended procedure for any backup system is to use different media for each day of the week and then to make a monthly archive. This way if an error is created in a file or files, you only have to restore a maximum of one month's data (in theory). If you have only one copy of your backup, you may not be able to restore your data. You may have copied the corrupted file to your backup. Believe me, I have seen this happen more than once.
By now I think you have reached the same conclusion I have. There is no perfect method of backing up a hard drive. Every method is a compromise. You do need to have a definite backup strategy for the time when your drive fails or your files become corrupted. First, you should have all of your original program disks in a safe location. This includes your Windows system disk. If your latest Windows version is an upgrade, then you should also have the original disk(s) from the previous version. If you have to fully restore a hard drive, Windows upgrade disks will ask for a previous version to verify that you are entitled to the upgrade. Secondly, keep a copy of any program updates, patches or applications downloaded from the Internet on some media other than your hard drive. A writeable CD is ideal for this purpose. These copies should be kept with your other original disks. Finally, keep a recent backup copy or copies of your data files. If you have financial data, tax data or other important files that you could not afford to loose, keep them backed up frequently. I use a backup program that copies every changed data file to a removable drive. In spite of that, I also copy my financial records to floppy disks. I could use an LS-120 dual-purpose drive or a Zip drive, and will, when the files exceed the capacity of a couple of floppies. Remember, the important thing is to select a method and then backup those drives!
*Dr. Lewis, a former university & medical school professor, is a computer consultant doing instruction, hardware/software services and system upgrades.
He is available to help you with your home or business computer problems. He does make house calls and can be reached via e-mail at bklew@worldnet.att.net or voice mail at 941/925-3047. :
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Copyright 1999. This article is from the December 1999 issue of the Sarasota PC Monitor, the official monthly publication of the Sarasota Personal Computer Users Group, Inc., P.O. Box 15889, Sarasota, FL 34277-1889. Permission to reprint is granted only to other non-profit computer user groups, provided proper credit is given to the author and our publication. We would appreciate receiving a copy of the publication the reprint appears in, please send to above address, Attn: Editor. For further information about our group, email: admin@spcug.org/ Web: http://www.spcug.org/
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