BIOS Configuration Settings
All recent laptop and desktop computers use either hard disks or solid-state drives (SSDs) that connect via SATA ports to the motherboard. SATA drives can be configured in the system BIOS in three ways:
Here are a couple of examples. In Figure 8.1, the SATA hard disk drives in this system are set to use AHCI. In Figure 8.2, the SATA drives use the older IDE mode setting.
Figure 8.1 SATA drives on this system use AHCI settings.
Figure 8.2 SATA drives on this system use IDE settings.
So, what do these settings mean?
- IDE—This setting makes the SATA drive act like PATA (IDE) hard disk drives that were once common in Windows-based systems. When this setting is used, the SATA drive can’t use advanced features, such as native command queuing and hot-plugging, and SATA 3Gbps and 6Gbps drives run at only 1.5Gbps.
- AHCI—This setting supports the SATA drives’ advanced functions.
- RAID—This setting is used on systems that use two or more drives as a logical unit (RAID 0, RAID 1, RAID 10, and so on).
When Windows is installed on an SATA hard disk, the configuration used in the BIOS or UEFI firmware is recorded in the Windows Registry. Windows checks the Registry at startup to determine how to access the drive. If the drive configuration has changed, Windows crashes.