VII BACKUP PROCEDURES What Is A Backup And Why Do It? Backup in its simplest form means "make a copy of". It is not uncommon for files to "get lost". The disk may "crash" (i.e. malfunction) or we may accidently delete an important file and the final result is that the file may be lost - irretrievably. The standard precaution for this potential disaster is to make backups of all important files. Files may be grouped into two catagories, those which often change and those which seldom or never change. Programs are an example of files which do not change. When you purchase a software system you obtain one and usually more files such as programs which will never change for as long as you are using the system. It is best to identify these files, back them up when you receive them and put the backup copies away in a safe place. Better yet, make two backup copies and store them in different locations. For example store one in a filing cabinet at home and the other at your place of work. Files which you frequently modify (such as the database files in LEGAL AID) should be frequently backed up. Option 4 of the File Utilities menu gives us a rudimentary backup function for LEGAL AID data files. All computer users should, however, have some understanding of proper backup procedures so that they can judge whether or not a particular backup procedure is sufficient for their environment. The following paragraphs should give you a fundamental understanding of many important aspects of backup procedures. Types Of Backups Full Backups: There are basically two types of backup procedures - Incremental Backups and Full Backups. Full Backups are just what the name implies. Copies are made of ALL files on a disk. Preferably the copies should be placed on another disk or a tape. A proper full backup should be stored "off-site", i.e. in a building other than the one housing the computer. This precaution is taken so that a fire will not likely destroy all copies of our data. A full backup should be done in such a manner that we will be able to completely reconstruct the state of the backed-up disk in the event we are required to restore lost files. Archived Full Backups: A special subclass of full backups is the Archived Full Backup. Ordinarily full backups are rotated. For example suppose we are using computer tape reels as our backup media and we are performing full backups every week. If we kept only 26 tapes for the purpose of performing full backups. We would be able to rotate (reuse) each tape every 6 months. Archived Full Backups, on the other hand, are never (or at least not for a very long time) reused. They are intended to be permanent records. Archived full backups are normally done at the end of the fiscal year and at the end of the calendar year. Incremental Backups: The second major type of backup is the Incremental Backup. Backups should be done every day if not more frequently. A general rule of thumb is don't leave any more data unbacked-up than you are willing to retype. However in the backup procedure mentioned in the paragraph above (weekly full backups) many files are backed up which have not changed since the last backup. A backup procedure which only backs up files which have changed since the last backup is called an incremental backup. Incremental backups have the advantage of being generally much faster than full backups but the disadvantage that it may be hard to locate a particular file since you often do not know what incremental backup tape it is on. Destroying Your Backup Copy There is a very significant problem which can occur with most personal computer backup procedures. It can often result in your backup data being completely destroyed. The following scenario will illustrate the problem. "Attorney Joe B. Careful faithfully performs full backups every day from his 20 Megabyte hard disk to a cassette tape. He has only one cassette tape which he has designated for daily backups of his data. Joe's secretary spent all day typing in the terms of an important and unusual contract for a client. Much of Joe's day is spent in consultation with the client and a consulting attorney to fix the terms of the contract. Finally it is finished and at the end of the day it is properly backed up. The next day Joe receives a phone call from the client asking for a few minor but technical modifications. Joe decides he will use the word processing system and make the changes himself. He inadvertently selects a wrong option (one having to do with data encryption) and exits the program. He has now transformed his proper contract into an apparent random sequence of characters. At the end of the work day Mr. Careful dutifully performs his full backup. The result of which is, of course, that the good backup of the good contract is replaced with garbage." There have been many, many different yet similar-in-outcome stories like this enacted throughout the history of computing. Nearly all of them could have been prevented with better backup procedures. A Backup Procedure There are many backup procedures which do the job. The exact details of a backup procedure appropriate to a particular installation depend upon the special requirements of the installation. I have never seen, however, what I would call a perfect backup procedure. Additionally, no matter how good a backup procedure is in theory it is useless in practice unless it is adhered to religiously. For illustration purposes I will present below a backup procedure for disk and tape which works reasonably well on medium sized computers. It may be too cumbersome for PC users but will serve as an illustration, nonetheless. Five sets of tapes are maintained. A set of tapes for daily incremental backups, another for weekly full backups, another for monthly full backups, another for quarterly full backups and finally a set for archived full backups. All sets are rotated except the set for archived full backups. Archived full backups are performed at the end of every fiscal year and every calendar year and are retained indefinitely. Ten tapes are kept in the daily incremental set. These are rotated every two weeks. At the end of every working day, except Friday, an incremental backup is performed. On Friday the weekly full backup is performed. It is performed on Friday since the probability of a fire or vandalism is at its highest on weekends. The weekly full backup set contains eight tapes and each is rotated (reused) every two months. Weekly full backups and all more infrequent backups are stored in a fire-proof vault in another building. At the end of the last working day of every month, except at the end of quarters, a full monthly backup is performed. There are six tapes in the monthly backup set and they are rotated every six months. At the end of each quarter, except at the end of the fiscal year and the end of December, quarterly full backups are performed. At the end of the fiscal year and at the end of December the archived full backups are created. Paper Backups Although many people thought that computers would quickly lead us into the "paperless society" that day is not in sight. In terms of backup procedures, paper can play a very useful role. I recommend keeping paper backups of the most important of your documents for several reasons. First, if irreplaceable legal documents in your care are lost you may be liable. Second, if backup procedures are not properly followed or if they are not perfect (none are) files may be lost and the paper document at least gives you the ability to type it in again. Third, you will sometimes find it inconvenient to have to access a document on the computer when you want to show it to someone else or make a quick check of something contained in it. However, make no mistake, there are certainly problems in store for those who rely on the paper copy and are not able to access the "live data". Paper copies tend to be out of date since no one wants to be continually updating paper files they seldom refer to. Also many documents will never make it to the paper file or they may only make it there long after they are first created, so you may not even be able to find what you are looking for. Backup Products And Disk Maintenance/Analysis Products There are a number of commercial packages on the market which help the user to perform backups. Many are capable of both incremental and full backups. There is even software included in PC-DOS and MS-DOS which will perform backups. I am not in a position to recommend or criticize any of these products. I will say, however, that if you are a hard disk user, "an ounce of prevention is worth a pound of cure". There are a number of products (such as the Norton Utilities) which will check your hard disk for errors and even fix some of them. I strongly recommend purchasing such a product and running at least once a week. Usually a hard disk which eventually crashes, displays symptoms over a period of time before the crash. A disk test program can identify these symptoms for you and allow you time to take corrective action (or at least prompt you to backup your data properly).