Chris Crayton is an author, technical editor, technical consultant, and trainer. Formerly, heworked as a computer and networking instructor at Keiser University; as network administrator for Protocol, a global electronic customer relationship management (eCRM) company; and at Eastman Kodak headquarters as a computer and network specialist. Chris has authored several print and online books on PC Repair, CompTIA A+, CompTIA Security+, and Microsoft Windows. Chris has also served as technical editor and contributor on numerous technical titles for many of the leading publishing companies. He holds MCSE, A+, and Network+ certifications.
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Introduction
This quick reference is a late-stage, exam-prep resource designed for use as a review shortly before your scheduled CompTIA A+ exams. It is not intended to be a comprehensive curriculum.
If you are using this resource, you should have already learned the material through a class or formal study method. This CompTIA A+ Quick Reference provides brief, straightforward explana-tions on major topics of the two CompTIA A+ exams: the 220-801 exam and the 220-802 exam.
Chapters 1 through 5 cover the five domains included on the 220-801 exam: Chapter 1, Hardware, is 40% of the exam. Chapter 2, Networking, is 27% of the exam. Chapter 3, Laptops, is 11% of the exam. Chapter 4, Printers, is 11% of the exam. Chapter 5, Operational Procedures, is 11% of the exam.
Chapters 6 through 9 cover the four domains included on the 220-802 exam: Chapter 6, Operating Systems, is 33% of the exam. Chapter 7, Security, is 22% of the exam. Chapter 8, Mobile Devices, is 9% of the exam. The final chapter, Chapter 9, Troubleshooting, is 36% of the exam.
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As you prepare for the exam, use this Quick Reference as an overall review of the exam topics. Each objective is discussed in this text. If you need more in-depth information about a topic, be sure to refer to your original study material.
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Chapter 1
Hardware
Hardware is one of nine domains on the 2012 CompTIA A+ exams. Hardware accounts for 40% of the 220-801 exam. Therefore, it is the most significant domain on either the 220-801 or 220-802 exams.
CPUs
The central processing unit (CPU) is the main processing unit of the personal computer (PC). It has an integral relationship with the motherboard and the system memory. These three devices control the data-processing aspect of the PC. Drives handle data storage, and input/output (I/O) interfaces allow human interaction, communication with peripherals, and network communication. The interaction between these components is controlled by the system BIOS or UEFI firmware.
Bit Versus 64-Bit CPUs
32-bit processors are designed to work with 32 bits of data at a time. This creates a limitation in the amount of installed memory they can access (4GB) and creates performance limitations when work-ing with large data sets and many programs running in memory at the same time. 32-bit processors are often referred to as x86 processors.
64-bit processors work with 64 bits of data at a time, and can use much larger amounts of RAM than 32-bit processors and provide faster performance. Although the first 64-bit processor to run some version of Microsoft Windows, the Intel Itanium, was not compatible with x86 software, 64-bit processors made for desktop computers are compatible with 32-bit or 64-bit operating systems and programs. 64-bit processors that can also run 32-bit software are often referred to as x64 or x86-64 processors.
Almost all CPUs released in 2009 or later support 64-bit operation, but support for 64-bit operation among older designs varies. To determine whether a particular processor is a 32-bit or 64-bit proces-sor, look up its specifications, or, if it is installed in a computer running Windows, use a utility such as CPU-Z (Figure 1-1).
2 CompTIA A+ Quick Reference
Figure 1-1 The processor in this computer is an AMD Phenom II X6 and it supports 64-bit (x86-64) instructions.
Clock Rate
The actual speed of the CPU is governed by a BIOS setting called the clock rate. CPUs run at a range of speeds, not just one specific speed. The speed can be varied by power management set-tings or by the BIOS in the event the processor overheats.
Although the latest processors from Intel and AMD have built-in overclocking options (overclock-ing is the process of running the processor and memory at faster performance than normal), most processors can be overclocked by manually adjusting the clock rate, voltage, and memory settings, if the motherboard and BIOS include these options.
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You can see the core speed of the CPU, its clock multiplier, and the bus speed displayed in some BIOS dialogs, or by using a program such as CPU-Z (refer to Figure 1-1).
Cores and Cache
The portion of the CPU that performs calculations and operations is known as the processor core. Until recently, CPUs contained only one core. To improve performance, some server and worksta-tion motherboards can support multiple CPUs (multiprocessor).
In recent years, most CPUs now include two or more cores. The term multicore processor applies to any processor with two or more cores:
Two cores Dual-core
Three cores Triple-core Four cores Quad-core Six cores Six-core
Chapter 1: Hardware 3
The more cores in a processor, the larger the number of programs and tasks it can run at the same time.
Table 1-1 lists some common multicore processors from Intel and AMD.
