15.01.2024 Views

CompTIA A+ Certification All-in-One Exam Guide

  • No tags were found...

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

AHCI

Current versions of Windows support the Advanced Host Controller Interface

(AHCI), an efficient way to work with SATA HBAs. Using AHCI unlocks

some of the advanced features of SATA, such as native command queuing

and hot-swapping.

Native command queuing (NCQ) is a disk-optimization feature for SATA

drives. It takes advantage of the SATA interface to achieve faster read and

write speeds that are simply impossible with the old PATA drives. Also,

while SATA supports hot-swapping ability, the motherboard and the

operating system must also support this.

AHCI mode is enabled at the CMOS level (see “BIOS Support:

Configuring CMOS and Installing Drivers” later in this chapter) and

generally needs to be enabled before you install the operating system.

Enabling it after installation will cause Windows to Blue Screen. How nice.

Successfully Switching SATA Modes Without Reinstalling

You can attempt to switch to AHCI mode in Windows without

reinstalling. This scenario might occur if a client has accidentally installed

Windows in Legacy/IDE mode, for example, and finds that the new SSD

he purchased requires AHCI mode to perform well.

First, back up everything before attempting the switch. Second, you

need to run through some steps in Windows before you change the

BIOS/UEFI settings. Windows 7 and 8/8.1 require manual changes to the

Registry (the database that handles everything in Windows, covered in

Chapter 12, “Windows Under the Hood”). Windows 10 uses an elevated

command prompt exercise with the bcdedit command. (The command line

is covered in Chapter 15, “Working with the Command-Line Interface.”)

A quick Google search for “switch from ide to ahci windows” will

reveal several excellent walkthroughs of the process for Windows 7/8/8.1

and Windows 10. Back everything up first!

When you plug a SATA drive into a running Windows computer that does

not have AHCI enabled, the drive doesn’t appear automatically. With AHCI

mode enabled, the drive should appear in Computer immediately, just what

you’d expect from a hot-swappable device.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!