A Data Survival Guide
- Published on Friday, 26 October 2007 16:02
What Went Wrong?
No matter how hard you try to “do the right thing,” someday you will probably encounter this message on your video display: “file not found.” Worse, it will probably be the most critical data you own. It’s one of Murphy’s Laws. You may even be faced with a storage device that simply does not respond. You’re caught without a backup and you need your data. Desperately! What can you do?
Do not panic! Consider this Rule #1. In most cases, your data is fully recoverable. However, to successfully recover your data, it is critical that you can confidently answer the question, “What happened?” If you can determine what event caused your data to become inaccessible, you have just taken the most important step toward recovering it. Listed below are the most common causes of data loss, and survival tips for each situation.
It happens to all of us. If your fingers go out of control and you accidentally erase a needed file (or files), don’t panic! If you have deleted a file under DOS, for example, you can use the “undelete” feature provided with DOS 5.0, or you can use the similarly-named utility that is provided with any number of disk utility packages. This is where Norton Utilities, PC Tools Deluxe, DosUtils and other disk maintenance/file recovery tool boxes pay for themselves.
The key to success is to undelete your erased file immediately. Once a file has been deleted, your computer will not hesitate to record new information in its place. If you or anyone else stores new data on the media that you were using, your file will probably be overwritten, thus preventing a successful recovery.
Disk Drive Mechanical Failure
Most users will find these types of problems difficult to identify, and if you suspect mechanical failure, you need to proceed carefully. If you know, for example, that your data has not been deleted yet you are unable to access it, you should consider the possibility that your disk drive is not functioning properly. Again, do not panic! But beware. In these situations, if you use file recovery software tools, you may cause irreparable harm to your data. Drives that are suffering mechanical or electrical failure are in no condition to be manipulating your data, any more than a drunk surgeon can operate.
Rule #2: Do not use file recovery software if you suspect an electrical or mechanical drive failure. You must correct the mechanical or electrical problem first, usually a job for an expert.
If your hard drive experiences a “head crash”--when the data write/read heads touch and thereby damage the surface of the media--there are no commercially available software packages that will help you. If you suspect a head crash situation, immediately turn off the power to your computer. The longer the heads are in contact with the media, the worse the problem will become. Believe it or not, data can be recovered from some head crash situations. But you will need expert help. Details in a moment.
Disk Drive Electrical Failure or Controller Card Failure
Again, if you know that you haven’t deleted the file you are trying to access, you may be experiencing this particular type of problem. We have observed that electrical failures occur more frequently than mechanical failures, so it would be a good idea to have an experienced technician replace the interface cards on your hard drive. These cards are available at larger computer stores, used computer dealers and repair shops, and drive repair companies.
Above all, remember Rule #2: do not use file recovery software until your drive and controller are functioning properly. Buyer beware: some file recovery programs claim to automate the retrieval of your data, and can be very useful in some situations. But if used on a drive with mechanical or electrical failure, these programs can cost you hundreds and thousands of dollars by actually destroying what was previously recoverable data!
General Data Corruption
This category consists of the most difficult data recovery challenges. General data corruption includes data loss due to viruses, errors introduced during a data compression process, corrupted or deleted directories or file allocation tables and other similar disasters.
If you have a virus, use the best anti-virus program available to detect and hopefully eradicate it. There are many such programs available, but I endorse Dr. Solomon’s Anti-Virus Toolkit as being the best overall package. If the virus has corrupted your data, you should check your backup (if you have one) for viruses as well. If your anti-virus software does not solve your problem, you should consult a data recovery expert who is prepared to deal with such issues.
Data compression is becoming more popular with users who wish to upgrade the hard disk capacity of their computer without replacing their hard drive. Although data compression is quite useful in serving its intended purpose, understand that a reliable backup is mandatory. If you are using data compression, and you experience any of the above electrical or mechanical failures, your chances for data recovery are greatly diminished. Traditional file recovery software packages cannot read or sort compressed data. In short, what you gain in increased disk capacity can be completely lost if you do not maintain a reliable backup.
Human error is without a doubt the number one data killer. Take for example the man whose toddler threw his laptop computer in the hot tub. Or the employee of a well-known tape backup manufacturer who had failed to backup their customer database. Or the network manager who had numerous backups of the network data, and trashed each backup, one after another, by repeatedly re-using faulty hardware.
Human error can cause data loss, and human errors can exacerbate the problem. We all make mistakes, but I would be particularly cautious of the “experts” you hire to service your system.
Whom Can You Trust?
Imagine that you or a loved one are ill. Whose help will you seek? An expert’s: a licensed physician. Imagine you have a problem with your car. Again, you seek out an expert: a licensed mechanic. If you experience a problem with your computer, you also seek out an expert. However, it has been my observation that we commonly make the mistake of defining a computer “expert” as anyone who knows more about computers than we do.
In the data recovery industry, we have seen hundreds of unrecoverable situations caused by “experts” who have misused file recovery utilities, opened up disk drives in an unsterile environment, and generally lacked the specialized expertise truly necessary to facilitate what should have been a successful recovery. We have seen one “expert” attempt to recover a single spreadsheet file and, with the aid of his file recovery utility, create 256 unrecoverable pieces of spreadsheet. We have seen disk drives opened up by “handymen” who simply wanted to “take a look under the hood,” so to speak. The smeared fingerprints on the media surfaces prevented a complete recovery.
Rule #3: Do not entrust your data to someone who lacks the training and expertise to solve your problem. And if you do, don’t be surprised if you’re told that your data is unrecoverable.
What about reentering the data yourself? While this option may appear inexpensive, the costs of rebuilding data are staggering. IDC Corporation estimated the cost of rebuilding just 20 megabytes of data, and the results for different types of data are shown in Figure 1.
Data recovery service is sometimes viewed as the last resort. In fact, when used as a first resort, professional data recovery service provides you with the best chance to return to business - your business, what you do best - as quickly and successfully as possible. By consulting an expert, your situation may prove to be easy for you to correct yourself (in the case of an accidentally deleted file, for example). If not, then the more valuable your data is to you, the safer you will feel in the hands of professionals.
Even data recovery experts vary in the quality of equipment, technological resources and skills they possess. So be sure you ask questions about their expertise with your particular situation:
- What is their success rate with your type of equipment and operating system (such as network file servers)?
- Do they have a clean room in the event that your drive must be opened under dust-free conditions?
- Will they be doing the work themselves, or sending it to another source?
- How quickly will your data be returned?
- Will your data be kept confidential?
- How long have they been in business?
- Can they provide you with references?
Remember that an outside inexperienced “expert” is no improvement over an in-house inexperienced “expert.” With so much at stake, you should be very selective.
Following the Rules
Proper planning will help you cope with any data loss disaster, even fires, floods, and earthquakes. If you plan to protect your data, it stands an excellent chance of survival. Follow the guidelines given here, and you need never give up on your data.
Michael Rogers is the CEO of Ontrack Data Recovery and Ontrack Computer Systems of Eden Prairie, Minn.
This article adapted from Vol. 5 #2.