Backup Strategies: Protecting Your Computer Files |
Aurora University
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When you do your work on your own desktop computer, it is your responsibility to make sure your data files are properly backed up. A variety of situations, accidental and deliberate, can destroy days, months, and even years worth of work in an instant, and if you don't have backups available, your only choice is to reconstruct the files from the beginning. Among the more common causes of file loss are hard disk crashes, floppy disk failure, damage to storage media, accidental erasure of files, and file corruption through mishandling, viruses, or power outages. Experienced users know the truth: it's not a matter of whether you will lose a file, but when. Backing up your files is essential. No single backup strategy is appropriate for every user, however, and each person's needs and ways of working are different. This document briefly describes some of the possible approaches. Find the combination of techniques that works best for you and make backing up your files a regular part of your work routine.
The most inclusive form of backup is to make a copy of the entire contents of your hard disk on a regular basis. This is a high-security but resource-intensive approach, consuming large amounts of storage space and possibly requiring hours to complete. Total system backups are suitable for multi-user systems, file servers, and certain special-use workstations, but for many users complete backups are at best unnecessary, and at worst complicated enough that users may come to the dangerous conclusion that backup is not worth the trouble. Your primary backup efforts should be directed towards your personal work files -- the unique documents, databases, spreadsheets, and image files that you have created using applications software. It is relatively easy to restore a lost applications program or even the operating system from the original installation disks, but your personal files are irreplaceable.
Saving previous versions of your work files. One simple safety measure is to maintain previous versions of the file you are working on. If something happens to your current work file, you can retrieve the previous version with only minimal loss of data. For example, if you are working on a document named myfile.doc, at appropriate intervals you could use the Save As feature of your application to change the name, using a sequence such as myfile1.doc, myfile2.doc, myfile3.doc, etc. The larger the number, the more recent the version. When the job is finished, you can delete all but the most recent version, and create an archival backup copy at that time. Advantages: protects against loss of most recent version, preserves your work process in case you want to return to an earlier approach. Disadvantages: no protection against hard disk crashes or other major disasters, since all the backups are on the same storage device; no backup for current version (unless your software application provides a auto-save utility).
Copying work files to an archive directory. Another easy form of backup is to keep copies of your work files on another part of your hard disk (in a special directory or folder called \backup or \archive, for example) using ordinary copy commands. Since the copies are stored in a different directory from the originals, it is possible for them to have the same names as the originals, which makes the backup process more orderly. If you have a large number of files, this can eventually consume a substantial amount of disk space, but compression techniques can be used to save space. It is also possible to set up batch programs that automate the process (see below). Advantages: cheap, easy, protects against inadvertent erasure or corrupted files caused by software failure. Disadvantages: no protection against hard disk crashes; can consume a great deal of disk space.
Maintaining duplicate files on external media. This is a good solution for quick, everyday backup (see list of media options below). This protects you both from accidental deletion of the originals and hard disk failures. USB drives are particularly good this purpose because they're fast and convenient to use. Except for CD-R/CD-RW disks, you can usually write to the alternative medium directly from the application by using File - Save As. One thing in particular to guard against is copying in the wrong direction: that is, copying a previous version of a file over a more recent version, thus destroying all your changes. It can happen! Stop and think before you copy -- the time and date attached to each file gives you the information you need to protect you against this problem. Here are some common storage media that can be used for this purpose:
- USB memory devices. These devices, also knows as memory sticks or flash memory cards, are the true successors to floppies. They are compact, high-capacity, relatively inexpensive, and reliable. If your PC has a spare USB port, this is the best option.
- CD-R and CD-RW. If your PC has a CD burner (most AU machines do) you can use writeable CDs for backup purposes. They are a little more trouble to use but have very high capacity and are therefore particularly good for occasional archival backups. CDs written in a CD burner can be used in any CD drive.
- Other high-capacity removable media. Examples include Iomega's Zip and Jaz drive system but there are others. If you own one it can be used for backup, but these types of drives are not typically found on PCs and you may have trouble finding a machine that can read from them. Writeable CDs are a better choice.
- Network drives. If you are on a local area network, you may be able to send your backups to a drive on a different computer -- consult your network administrator for details. AU's S: drive, located on the Novell server, is available to all AU users for this purpose.
- Another PC. One type of "alternative medium" is a second computer: if you frequently work in two separate locations (say, at work and at home), a good backup strategy is to keep current versions of all your work files on each machine.
Advantages: cheap and easy; in many cases requires no special hardware; protects you from both hard disk crashes and human error. Disadvantages: can be labor-intensive if you have a lot of files to keep track of; risk of destroying a more recent version of a file by copying in the wrong direction.
Storing your files on the Novell server. Most users with current computer accounts at Aurora University have access to the Novell local-area network. If you have a Novell account and are working from a networked PC on campus, you may choose to save your data files on the network drive instead of the C: drive of your local computer. Typically your designated network drive will be the K: drive (or the S: drive, if you are sharing access with a group of users). Since files stored on the networked drive are backed up regularly by Information Technology Services staff, you can provide for backup services without doing any extra work. Another way of using the networked drive, offering an added measure of security, is to keep your main files on your local file and a backup copy on the network drive (or vice-versa). The same backup principles apply here, except that typically the main working versions of your files will be on the server, not your local hard disk. Under these circumstances, you may want to use your local hard disk to keep backup versions of important files, to guard against not only Novell system failures, but also accidental deletions made by others who have access to the networked version of the files (a particular risk for files stored on the S: drive). There's no substitute for backup files that are completely under your personal control.
In addition to the various backup strategies described above, there are different ways to copy the files themselves.
Simple copying. You can use your computer's copy commands to make backups. On MS Windows machines, this can be accomplished in three different ways. First, you can create additional copies of a file within an application using the Save As command (or equivalent) to send a file to an alternative storage location, or to a file with a slightly different name, or both. Second, you can use Windows' file copy/move functions to make copies of files or entire folders. Third, if you are familiar with DOS commands, you can open up a DOS window and use the native copy commands from the system prompt. For example, the command copy c:\msword\*.doc k:\backup copies all the files ending in ".doc" to the backup folder on your K: drive.
- How often should I back up my files? There is no simple answer to this question. Ask yourself this: how much can I afford to lose? No one should fail to keep at least one backup copy of any file whose loss would cause even minor inconvenience. For most users, a mixed solution works well: back up important files daily or after every revision, and run more general backup routines weekly or less.
- What should I do if I'd like to back up my files but don't want to have to think about it? Many types of backup processes can be automated to run at scheduled times or when specific events occur (for example, every time you start your computer). Once these systems are in place, they can run more or less unattended. Contact ITS for further information on setting up an automated backup process. Storing your data files on the Novell network drive is another low-effort strategy, since files on the Novell server are backed up regularly by ITS staff.
- What if I have to work from a public workstation? Users without access to their own personal computers may be forced to keep their work files on floppy disks, or (better) USB drives. If this is your situation, you should always make an original and an identical backup copy on separate media.
- How do I keep track of my backup files? A poorly labeled or lost backup file is the functionally the same as no backup at all. Make sure your backups files are labeled in a way that makes it easy for you to locate and identify them. For critical files, keeping a set of backups at another location is good idea.
- How can I make the backup process easier? One useful technique is to keep all of your work files in a single directory or folder. You can use the folder \My Documents provided as a default in Windows, or create your own folders with names like \work or \data, using subdirectories to maintain order. If you know all of your data files are stored in this hierarchy, it's an easy matter to back up the entire set of files. Data files that end up being scattered all over the hard disk are much more difficult to locate and back up. If you decide to use archiving software to create backups, give the files appropriate names. All of your sent email for the year, for example, could be stored in a file called sent97.zip.
- What is the most reliable approach to backup? It's important to recognize that there are no perfectly reliable approaches to backup. Any system can fail, and probably will at some point. In this context, redundancy is your best friend. Keeping second and even third copies of important files using different storage media may require extra work, but it could save you aggravation later on. It's also worth noting that no backup system, however reliable, is worth anything if you don't use it.