CompTIA A_ Certification All-In-One Exam Guide, Seventh Edition - Michael Meyers [173]
The autodetection screen indicated that you installed a PATA drive correctly. If you installed a hard drive on the primary controller as master but messed up the jumper and set it to slave, it showed up in the autodetection screen as the slave. If you had two drives and set them both to master, one drive or the other (or sometimes both) didn’t appear, telling you that something was messed up in the physical installation. If you forgot to plug in the ribbon cable or the power, the drives wouldn’t autodetect.
SATA changed the autodetection happiness. The SATA world has no such thing as master, slave, or even primary and secondary controller. To get around this, motherboards with PATA and SATA today use a numbering system—and every motherboard uses its own numbering system! One common numbering method uses the term channels for each controller. The first boot device is channel 1, the second is channel 2, and so on. PATA channels may have a master and a slave, but a SATA channel has only a master, because SATA controllers support only one drive. So instead of names of drives, you see numbers. Take a look at Figure 11-45.
Figure 11-44 Old standard CMOS settings
Whew! Lots of hard drives! This motherboard supports the traditional four PATA drives, and it also supports four SATA drives. Each controller is assigned a number; note that channel 1 and channel 2 have master/slave settings, and that’s how you know channel 1 and 2 are the PATA drives. Channels 3 through 6 are SATA, even though the listing says master. (SATA is still somewhat new, and a CMOS using incorrect terms such as master is common.)
Figure 11-45 New standard CMOS features
Boot Order
If you want your computer to run, it’s going to need an operating system to boot. While the PCs of our forefathers (those of the 1980s and early 1990s) absolutely required you to put the operating system on the primary master, most BIOS makers by 1995 enabled you to put the OS on any of the four drives and then tell the system through CMOS which hard drive to boot. With the many SATA drives available on modern systems, you’re not even limited to a mere four choices. Additionally, you may need to boot from an optical disc, a USB thumb drive, or even a floppy disk (if you’re feeling retro). CMOS takes care of this by enabling you to set a boot order.
Figure 11-46 shows a typical boot-order screen, with a first, second, and third boot option. Many users like to boot first from optical and then from a hard drive. This enables them to put in a bootable optical disc if they’re having problems with the system. Of course, you can set it to boot first from your hard drive and then go into CMOS and change it when you need to—it’s your choice.
Figure 11-46 Boot order
When you see the error Invalid Boot Disk, the system is trying to boot to a non-bootable disk. Remove any devices before the device you want to boot in the boot order.
Enabling AHCI
On motherboards that support AHCI, you implement it in CMOS. You’ll generally have up to three options: IDE or compatibility mode, AHCI, or RAID. Use compatibility mode to install older operating systems, such as Windows XP. Going to AHCI or RAID enables the AHCI option for the HBA.
Device Drivers
Devices that do not get BIOS via the system BIOS routines naturally require some other source for BIOS. For ATAPI devices and many SATA controllers, the source of choice is software device drivers, but both technologies have a couple of quirks you should know about.
ATAPI Devices and BIOS
ATAPI drives plug into an ATA controller on the motherboard and follow the same conventions on cabling and jumpers used by PATA hard drives. In fact, all current CMOS setup utilities seem to autodetect optical-media ATAPI drives. If you go into CMOS after installing a CD-ROM drive