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As a last resort, you can back up a hard-disk drive’s contents on diskettes, a method
that is both tim e-con suming a nd pro ne to h uman error. Also , backing up a full 5 40-MB
hard-disk drive requires approximately 375 diskettes (when using 1.44-MB diskettes).
Therefore, if it is abso lutely necessary to use diskettes as backup devices, any
unwanted hard-disk drive files should be deleted before a backup procedure is
started.

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Some hard-disk drive failures are recoverable. In these cases you may be able to
recover all lost data if the proper utility software is available. Even losses suc h as acci-
dentally deleted files or accidental reformatting of a hard-disk drive can be reversed
with these utilities.
If the computer system is running MS-DOS, many apparent data loss problems are
due to corruption or erasure of the hard-disk drive’s master boot record (MBR),
MS-DOS boot sector, or file allocation table (FAT). That is, accidental deletion of files
or accidental reformatting of the hard-disk drive alters the MS-DOS boot sector, the
FAT, and the root directory.
Ho we v er, suc h accide nts do not act ual ly erase the c ontents of t he hard-disk dri ve fil es
until new data is written to the sectors containing these files. With software such as
the Norton Utili ties, Mac e Utilities , or PC-Tool s Delux e, the data stored in the se areas
can often be restored, meaning that you can recover most, if not all, of the data.
Unlike formatting a hard-disk drive, formatting a diskette completely erases all the
data on the diskette unless you use the diskette formatting program included in the
Mace Utilities.
For a complete description of data recovery procedures and the software needed to
perform them, see

The Paul Mace Guide to Data Recovery

, published by Brady.

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An e xh au st fan in the power supply c ool s the power su ppl y and c omp ute r by drawing
air in throug h v arious op enings in the com puter an d blo win g it out the back. Ho w e v er,
the fan also draws dust and other particles into the computer, causing contaminant
buildup, which results in an increase in the system’s internal temperature and inter-
feres with the operation of various system components.
To avoid these co ndi tions, D ell rec om men ds keeping y ou r work env iro nme nt c le an to
reduce the amount of dust and dirt around the computer, thereby reducing the
amount o f co ntamina nts drawn in to the co mpu ter by the po wer supply fan. In pa rtic u-
lar, you should keep the exterior of your computer and monitor clean, and you should
use a commercially available diskette-drive he ad-cleaning kit t o remove contaminants
inside your diskette drives.
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