Once in awhile your defrag program will report it has encountered an error and tells you to run Scandisk. This is a program designed to find those errors and fix them. While the Scandisk program that ships with win95 (or DOS 6) is not as robust as, say, the one included with Norton's Utilities, for the average user it is more than adequate at helping to keep your hard drive in tip-top shape.
What does Scandisk fix? Lost chains and clusters. Lost file fragments. What are those? These are segments of files that have somehow become seperated from their original file. Many times these are caused by a sudden interuption, such as losing power or hitting the reset button, as your hard disk is writing information to the drive. What I have learned over time is that these lost chains are more like ghost images that will appear and confuse the computer.
If you do not already have Scandisk installed, see the defrag page for instructions on how to add this component to your win95 system. Once you start Scandisk you will see a dialog with several options. (**picture available**)
You can have Scandisk examine one, some or all of your hard drives and floppies. If you want to scan multiple disks, click on the first one. Then hold down the control key as you select other drives. This will highlight those drives so Scandisk will know they are the ones you want to examine.
By clicking on the Advanced button in the lower right you bring up a dialog (**picture available**) showing the settings you can change. If you examine the picture carefully you will see the settings I recommend. The only option I would change from what I show is if you are using disk compression. In that case you will want to put a check next to Check Host Drive First in the lower right.
The Options button presents you with more choices. (**picture available**) Unless you have a lot of time to wait, I do not recommend chosing the write-testing options. That option will write and read to every available sector on your hard drive. The larger your hard drive, the longer that will take. A 1.6 gigabyte hard drive takes approximately 25 minutes to complete that test.
Once you have Scandisk set up, click on the Start button. If you use my suggestted settings when the program is done it will present a report to you. This report will explain what Scandisk found and if it repaired anything. I only include that option in order to find out what was wrong and what was done during the operation.
The surface scan will give Scandisk a chance to examine your entire hard drive to find any bad sectors. Once found, if there are any, it will mark those sectors as unusable so that you don't risk losing your data by trying to write to the bad sectors. All hard drives, no matter how reliable or well-built they are will eventually have bad sectors. As long as the total number of bad sectors is less than 2% of your total hard drive, I wouldn't worry about it. If it exceeds 2% I would keep an eye on the drive. If the number of bad sectors continues to increase at a steay rate, contact the manufacturer of your hard drive.
I've used Maxtor and Western Digital drives a-plenty. Of the five drives I've used, only one has ever shown a tendency to fail on me. A call to Western Digital and I had a replacement drive within a week. You have to love those three year warranties and the no-haggle policy of the major drive makers.
How often should you run Scandisk? That depends. How often does the defrag program report errors? How often does power fail while you are using the computer? In general, run the program about once a month. Whatever errors crop up in that time will be fixed and you can keep your hard drive tuned for optimal performance. One tip. Always run Scandisk before you run the defrag program.