Tips to Prevent Hard Disk Problems

Do as I say... Not as I do!

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Recently, I ran across an article from the University of Kansas Transpor­tation Center, KUTC newsletter Vol. 10, No.3, about hard disks inmicrocomputers. Essentially, there are two type of disks: floppy disks andhard disks. The main advantage of the hard disk is that it can hold atremendous amount of information. Where a common floppy can holdthousands of bytes of information (one letter character on this page canbe thought of as using up one byte of memory), a common hard disk canhold millions of bytes. The problem comes when something goes wrongwith your hard disk -- you can loose millions of bytes of information infleeting second,

Having personally experienced that sickening feeling which enters intoyour stomach after a major hard disk failure I found the article belowto be worthwhile sharing. In particular, I would like to emphasize the sec­tion about parking the disk head before power-off. Now that I'm $300.00smarter, I will always take the time to park my disk. All I want is a reliablecomputer, not an atom smasher. When the head and disk collide its aterrible lonely mess.

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Installing a 10- or 20-mt?gabyte, or evenlarger, fixed disk in your microcomputersystem means a number of things, especiallyin comparison to a diskette-based system.The visible advantages are obvious: a varietyof software can be installed once and thenbe available at any time without the use ofdiskettes; storage space is dramaticallyincreased; diskette handling can be reducedto a minimum; disk access is much fasterthan with diskettes; and all data andsoftware on the disk are only a few key­strokes away. These benefits tend to createa "set it and forget it" attitude that can betroublesome.

Along with the hard disk's visibleadvantages come some unseen characteris­tics that have the potential to wreak havocwith your disk, files, and patience. Some ofthese characteristics are: "next availablespace" writing of data; likelihood ofduplicate file names in different subdirecto­ries; possibility of the read/write headcrashing under certain circumstances; andvast space available for old files and lostdafa to accumulate. Careful attention tomanagement and maintenance of the harddisk can help prevent problems fromoccurring and keep the system's perform­ance from dragging. Let's look at somespecific techniques.

Keep the information on the disk organ­ized.

Periodically go through the entiredirectory and delete out-of -date and unnec­essary files and sub-directories. Old datathat you want to retain should be copied todiskettes if quick access to it is not essential.If there is any uncertainty as to the contentsof a file, determine its contents before

deleting it. A variety of utility programs areavailable to help speed up the process ofexamining, deleting or copying largenumbers of files by selecting files from a listinstead of typing each filename.

It's a good idea to run the DOS check­disk utility, CHKDSK, every so often toverify the integrity of data stored on the diskand to retrieve any lost data that may exist.Lost data clusters can appear for variousreasons and will tie disk space untilremoved. CHKDSK reports space alloca­tion, memory size and whether allocationerrors are found. It only corrects errorswhen the fix switch is specified in thecommand line, CHKDSK/F. Lost clusterscan then be written to files, which can beexamined and recovered or erased.

Periodically reorganize the disk.Because data is written to the disk in

the first available location, a file's contentstend to get scattered in different locations asthe file is repeatedly edited. This isn't aproblem except that as the read/write headhas to move around the disk more to accessthe file, disk access is slowed. To maintainthe best performance, files should be. .rewritten to contiguous locations every sooften. The DOS command CHKDSKpath*.*will reveal which files have becomefragmented and into how many locations. Adisk-optimization utility program willreorganize the files on hard disk, rewritingall files into contiguous blocks.

Park disk head before power-ofT.The read/write heads on a hard disk in

effect "fly" at high speed a minute distanceabove the surface of the disk platters.

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When power is shut off, the heads touchdown on the surface of the disk, each timewearing away the surface of the disk a tinybit. Eventually, accumulated wear couldcause data loss. More importantly, if themachine, with heads resting on the data areaof the disk, is moved, bumped, or jostled,the surface of the disk may become pitted ordamaged. Later, with the disk spinning, theturbulence created above the damaged spotmay cause the head and disk to collide,destroying both.

The solution to both problems is toensure that the heads are parked in a safezone before power is shut off. This isrecommended for every time the computeris turned off, but it is imperative, if thecomputer is going to be moved. Some disks,using voice-coil technology to position theheads, automatically perform this function.All others, including the less expensive .stepper-motor types, require a program thatsends the heads to the parking zone. Manycomputer manufacturers include such aprogram with their operating system ordiagnostic software. Although otherparking programs are available, using theone written for your particular machine isrecommended since disk-control technologymay vary. Ifyour hard disk-equippedcomputer didn't come with a disk parkingutility, ask the dealer or manufacturer whynot.