Chapter 15 PC Troubleshooting 675
Preparation for Installing or Upgrading an
Operating System
Before installing a new operating system, several appropriate practices should
be followed for the ideal setup:
✔ Check for viruses.
✔ Defrag the drive.
✔ Read the
readme.txt
file.
✔ Check the operating system’s Web site for latest updates, known installation
problems, hardware compatibility lists, patches, and updates.
If you are upgrading an existing system, be sure to backup existing system
data. You are probably tired of hearing “back up the system data,” but it is
the only way to rebuild a destroyed system. There are two commonly accepted
methods of backing up files: incremental and differential.
The difference between the two is determined by the archive bit. The archive
bit is designed to indicate if a file has been backed up or not. This issue is
important on large data systems where backups are performed daily to ensure
against data loss.
An incremental backup requires a disk or tape for each daily backup. When
performing an incremental backup, only the changes in data since the last
incremental or last full backup are copied. A copy of the last full data backup
plus each incremental backup in sequence must be used to reconstruct an entire
collection of data, Figure 15-30. When performing a differential backup, all
the data changes are copied since the last full backup. Only one disk or tape is
needed to perform the differential backup because it copies all changes in data
since the last full backup was performed. To restore the data, you need only the
last full backup and the last differential backup.
Figure 15-29.
Data on a hard drive
that stops working
can often be accessed
using special
software. Here a file
is being viewed in
Norton’s Disk Editor.
incremental backup
operation that backs
up select files that
have changed since
the last backup of
files. The archive bit
is reset.
differential backup
operation that
saves files that have
changed since the
last full backup of all
files. The archive bit
is not reset.