CompTIA A+ Certification All-in-One Exam Guide, Exams 220-1001 & 220-1002

by Mike Meyers

Hybrid Hard Drives

Windows supports hybrid hard drives (HHDs), drives that combine flash memory and spinning platters to provide fast and reliable storage.

(HHDs are also known ...

The small SSD in these drives enables them to store the most accessed data in the flash memory to, for example, slash boot times and, because the platters don’t have to spin as much...

Apple computers can use a Fusion Drive, which offers the same concept as a hybrid hard drive. The Fusion Drive separates the hard drive and SSD; macOS does all the w...

Connecting Mass...

the most important to CompTIA A+ techs being ATA/ATAPI.

PATA and SATA. Parallel ATA (PATA) was introduced with ATA/ATAPI version 1. Serial ATA (SATA) was introduced with

ATA/ATAPI version 7. Let’s look at both standards.

NOTE ATA hard drives are often referred to as integrated drive electronics (IDE) drives. The term IDE refers to any hard drive with a built-in controller. All hard drives are technically IDE drives, although we only use the term IDE when discussing PATA drives. Many techs today use IDE only to refer to the older PATA standard.

PATA

PATA drives used unique 40-pin ribbon cables.

Note that the exam will call these IDE cables.

All PATA drives used a standard Molex p...

NOTE The last ATA/ATAPI standard that addressed PATA provided support for very large hard drives (144 petabytes [PB], more than 144 million gigabytes) at speeds up to 133 megabytes per second (MBps).

A single PATA ribbon cable could connect up to two PATA drives—including hard drives, optical drives, and tape drives—to a single ATA controller.

You set jumpers on the drives to make one master and...

ATA/ATAPI version 3 introduced Self-Monitoring, Analysis, and Reporting Technology (S.M.A.R.T.), an internal drive program that tracks errors and error conditions within the drive.

This information is stored in nonvolatile memory on the drive and can be examined externally with S.M.A.R.T. reader software.

SATA

PC, parallel ATA had problems. First, the flat ribbon cables impeded airflow and could be a pain to insert properly. Second, the cables had a limited length, only 18 inches. Third, you couldn’t hot-swap PATA drives.

SATA creates a point-to-point connection between the SATA device—magnetic hard drives, solid-state drives, optical media drives—and the SATA controller, the host bus adapter (HBA).

SATA hard disk power (left) and data (right) cables

Because SATA devices send data serially instead of in parallel, the SATA interface needs far fewer physical wires—only 7 connectors instead of the 40 typical of PATA—resulting in much thinner cabling.

Further, the maximum SATA-device cable length is more than twice that of a PATA cable—about 40 inches (1 meter) instead of 18 inches.

EXAM TIP The CompTIA A+ 1001 exam objectives refer to the 40-pin PATA ribbon cable as an IDE cable. They’re the same thing, so don’t miss this one on the exam!

SATA did away with the two drives per cable of PATA. Each drive connects to one port. Further, there’s no maximum number of drives—many motherboards today support up to eight SATA drives (see Figure 8-13). Want more? Snap in a SATA HBA and load ’em up!

SATA devices transfer data in serial bursts instead of parallel, as PATA devices do.

a SATA device’s single stream of data moves much faster than the multiple streams of data

coming from a parallel ATA device—theoretically, up to 30 times faster.

SATA drives come in three common SATA-specific varieties: 1.5 Gbps, 3 Gbps, and 6 Gbps, which have a maximum throughput of 150 MBps, ...

It should be noted that if a system has an (external) eSATA port (discussed next), it will operate at the same revision an...

NOTE Number-savvy readers might have noticed a discrepancy between the names and throughput of SATA drives. After all, SATA 1.0’s 1.5-Gbps throughput translates to 192 MBps, a lot higher than the advertised speed of a “mere” 150 MBps. The encoding scheme used on SATA drives takes about 20 percent of the transferred bytes as overhead, leaving 80 percent for pure bandwidth. SATA 2.0’s 3-Gbps drive created all kinds of problems because the committee working on the specifications was called the SATA II committee, and marketers picked up on the SATA II name. As a result, you’ll find many hard drives labeled “SATA II” rather than 3 Gbps. The SATA committee now goes by the name SATA-IO. In keeping with tradition, when SATA II speed doubled from 3 Gbps to 6 Gbps, two names were attached: SATA III and SATA 6 Gbps.

Hot-swapping entails two elements, the first being the capacity to plug a device into the computer without harming either. The second is that once the device is safely attached, it will be automatically recognized and become a fully functional component of the system. SATA handles hot-swapping just fine in modern systems (see “AHCI” later in the chapter for more details).

SATA Express (SATAe) or SATA 3.2 ties capable drives directly into the PCI Express bus on motherboards. SATAe drops both the SATA link and transport layers, embracing the full performance of PCIe.

The lack of overhea...

enhances the speed of SATA throughput, with each lane of PCIe 3.0 capable of handling up to...

A drive grabbing two lanes, therefore, could move a whopping 16 Gbps through the bus. Without the overhead of earlier SATA ver...

SATAe has unique connectors (see Figure 8-14) but provides full backward compatibility with earlier versions of SATA. Note that the center and left portions of the port look just like regular SATA ports? They function that way too, so you can plug two regular SATA drives into a SATAe socket. Feel free to upgrade your motherboard! Oh yeah, did I forget to mention that? You’ll ...

EXAM TIP Each SATA variety is named for the revision to the SATA specification that introduced it, with the exception of SATAe: • SATA 1.0: 1.5 Gbps/150 MBps • SATA 2.0: 3 Gbps/300 MBps • SATA 3.0: 6 Gbps/600 MBps • SATA 3.2: up to 16 Gbps/2000 MBps, also known as SATAe

NOTE The SATA 3.3 (2016) revision increased supported drive sizes, among other things. The throughput speed of the interface did not increase.

Essential Peripherals

Serial Ports

A serial port manifests as a 9-pin, D-shell male socket, called a DB-9 or an RS-232.

EXAM TIP You don’t need to know how serial ports work to get through the CompTIA A+ 1001 exam. Just remember the names of the ports and connectors, DB-9 and RS-232.

USB Ports

Universal serial ...

Every USB root hub is a bus, similar in many ways to an expansion bus.

A single host controller supports up to 127 USB devices,

AMD X370 chipset supports 16 USB ports,