Computer Hard Drives: Types, Structure, and Setup

Hard Drives: Types and Fundamentals

The two most common types of hard drives are IDE (Integrated Drive Electronics) and SATA (Serial Advanced Technology Attachment).

Physical Structure of Hard Drives

Hard drives serve as the primary mass storage unit of a computer. They typically contain multiple platters stacked on a central spindle, completely isolated from the outside environment. At the bottom of the hard disk is a circuit board (or controller card) that receives commands from the system controller. This board also ensures that the spindle maintains a constant rotational speed and manages when the unit reads from or writes to the disk. Modern disks commonly reach speeds of 7200 RPM (revolutions per minute).

A group of read/write heads, mounted on actuator arms, positions itself over the surface of the platters. These heads align with the tracks, which are concentric circles formed on the platter surfaces. The heads write information from the disk controller onto the platters by orienting the magnetic particles on their surface. They also read information by detecting the polarity of the already oriented particles.

When software requests the operating system to read or write a particular sector of the disk, the operating system instructs the hard disk controller to move the read/write heads to the track containing that sector. The read/write heads then wait for that specific sector to pass beneath them to perform the read or write operation.

Installation and Configuration

1. For IDE drives, configure the hard drive as Master or Slave using jumpers.
2. Mount the drive securely in an available bay within the computer case.
3. Connect the appropriate data cable: a 40-pin or 80-conductor ribbon cable for IDE, or a 7-pin cable for SATA.
4. Connect the power cable from the power supply unit to the hard drive.
5. Configure the drive settings in the computer's BIOS/Setup utility.
6. Partition the disk to create logical storage areas.
7. Format each partition to prepare it for data storage.
8. If it's the primary drive, install the operating system onto it.

BIOS/Setup Configuration

Most modern BIOS versions offer an autodetection option that automatically identifies the characteristics of the installed drive. If autodetection fails, it could be due to several reasons:

• The data cable connecting the drive to the motherboard or controller card is incorrectly connected.
• The drive has not been properly powered.
• The disk capacity exceeds the limits supported by the current BIOS version.
• The hard drive itself is damaged.

IDE Drive Considerations

Older IDE drives often have limitations regarding supported capacities. Overcoming these barriers sometimes requires modifying the BIOS, typically by enabling or updating to EBIOS LBA (Extended BIOS Logical Block Addressing) support. In some cases, it may be necessary to update both the system BIOS and the hard drive's firmware or controller driver.