As a technician, you might have to perform a clean installation of an OS. Perform a clean install in the following situations:
- When a computer is passed from one employee to another
- When the OS is corrupt
- When the primary hard drive is replaced in a computer
The installation and initial booting of the OS is called the operating system setup. Although it is possible to install an OS over a network from a server or from a local hard drive, the most common installation method for a home or small business is with CDs or DVDs. To install an OS from a CD or DVD, first configure the BIOS setup to boot the system from the CD or DVD.
Important: If the hardware is not supported by the OS, you may need to install third party drivers when performing a clean installation.
A hard drive is divided into specific areas called partitions. Each partition is a logical storage unit that can be formatted to store information, such as data files and applications. During the installation process, most operating systems automatically partition and format available hard drive space.
A technician should understand the process and terms relating to hard drive setup.
- Primary partition - This primary partition containing the operating system files is usually the first partition. There can be up to four primary partitions per hard drive. A primary partition cannot be subdivided into smaller sections.
- Active partition - The OS uses the active partition to boot the computer. Only one primary partition per disk can be marked active. In most cases, the C: drive is the active partition and contains the boot and system files. Some users create additional partitions to organize files or to be able to dual-boot the computer.
- Extended partition - The extended partition normally uses the remaining free space on a hard drive or takes the place of a primary partition. There can be only one extended partition per hard drive, but it can be subdivided into smaller sections called logical drives.
- Logical drive - A logical drive is a section of an extended partition. It can be used to separate information for administrative purposes.
- Basic disk - A basic disk (the default) contains primary and extended partitions, as well as logical drives. A basic disk is limited to four partitions.
- Dynamic disk - A dynamic disk has the ability to create volumes that span across more than one disk. The size of the partitions can be changed after they have been set. Free space can be added from the same disk or a different disk, allowing a user to efficiently store large files. After a partition has been extended, it cannot be shrunk without deleting the entire partition.
- Formatting - This process prepares a file system in a partition for files to be stored.
- Sector - A sector contains 512 bytes.
- Cluster - A cluster is also called a file allocation unit. It is the smallest unit of space used for storing data. It is made up of one or more sectors.
- Track - A track is one complete circle that can contain data on one side of a hard drive platter. A track is broken into groups of sectors.
- Cylinder - A cylinder is a stack of tracks lined up one on top of another to form a cylinder shape.