Comptia A+ Terms Flashcards
(199 cards)
1
Q
RAM
A
random access memory
stores programs and data currently being used by the CPU
2
Q
CPU
A
central processing unit,
also microprocessor
3
Q
BIOS
A
basic input-output system
4
Q
ROM
A
read-only memory
5
Q
OS
A
operating system
6
Q
GPU
A
graphics processing unit
7
Q
DC
A
direct current
8
Q
AC
A
alternating current
Electricity comes in two flavors: direct current (DC), in which the electrons flow in one direction around a continuous circuit, and alternating current (AC), in which the flow of electrons alternates direction back and forth in a circuit.
9
Q
NIC
A
network interface card
10
Q
FRU
A
field replaceable unit
11
Q
plug
A
A plug is a part with some type of projection that goes into a port.
12
Q
port
A
A port is a part that has some type of matching hole or slot that accepts the plug.
13
Q
jack
A
The term jack is used as an alternative to port, so you may also put a plug into a jack.
14
Q
connector
A
The term connector describes either a port (jack) or a plug.
15
Q
DIN
A
Deutsche Industrie Norm
16
Q
PS/2
A
Personal System 2
17
Q
USB
A
Universal Serial Bus
18
Q
FireWire
A
also known as IEEE 1394
19
Q
DB connectors
A
Technically, they’re known as D-sub or D-subminiature connectors, but most techs call them DBs. CompTIA calls them D-shell connectors, so don’t be surprised by that term either.
20
Q
D-shell
A
DB Connectors. Technically, they’re known as D-sub or D-subminiature connectors, but most techs call them DBs. CompTIA calls them D-shell connectors, so don’t be surprised by that term either.
21
Q
RJ connector
A
the RJ-11 and the RJ-45. The phone jack is an RJ-11. It is used almost exclusively for modems. The slightly wider RJ-45 jack is used for your network connection.
22
Q
RJ-11
A
The phone jack is an RJ-11. It is used almost exclusively for modems.
23
Q
RJ-45
A
RJ-45 jack is used for your network connection.
24
Q
1/8-inch connector
A
mini-audio connector
25
S/PDIF
Sony/Philips Digital Interface Format (S/PDIF) connection. S/PDIF comes in coaxial and optical versions.
26
mini-DIN
Most keyboard plugs and mini-DIN keyboard ports are colored purple.
A mouse uses either a USB port or a dedicated, light-green mini-DIN connector.
27
VGA
Video Graphics Array
28
DVI
digital visual interface
29
DVI-D
The DVI connector comes in three flavors: DVI-D (all digital), DVI-A (analog), and DVI-I (both digital and analog).
30
DVI-A
The DVI connector comes in three flavors: DVI-D (all digital), DVI-A (analog), and DVI-I (both digital and analog).
31
DVI-I
The DVI connector comes in three flavors: DVI-D (all digital), DVI-A (analog), and DVI-I (both digital and analog).
32
HDMI
High-Definition Multimedia Interface
33
VESA
Video Electronic Standards Association
34
mDP
DisplayPort has both a full-sized connector and a smaller one, called **Mini DisplayPort** (mDP).
35
modem
modulate - demodulate
36
DVD
digital versatile disc
37
I/O
input/output
38
ESD
electrostatic discharge
39
DIMM
dual inline memory module
40
TB
terabyte
41
CD-ROM
compact disk - **read only memory**
42
CR-R
CD-R (**recordable**: you can change the data once)
43
CD-RW
CD-RW (**rewritable**: you can change the data on them over and over).
44
MB
megabytes
45
GB
gigabytes
46
LCD
liquid crystal display (or is it liquid crystal diode)
47
CRT
cathode ray tube
48
MSDS
Material Safety Data Sheet
49
AMD
Advanced Micro Devices
50
ALU
arithmetic logic unit
51
Registers
memory circuits located inside the CPU that hold data before and after processing.
52
FPU
floating-point unit
53
SRAM
static RAM
54
cache
Modern CPUs have two sets of ultra-fast static RAM (SRAM) memory built in, called **cache**.
55
L1
The Level 1 (L1) cache memory is the first and fastest and is built into the processor.
56
L2
Level 2 (L2) cache memory is the second cache.
57
package
The ceramic casing that holds the CPU is called the **package**.
58
die
The ceramic casing that holds the CPU is called the package. The silicon wafer that has all the transistors is called the **die**.
59
on-die
The ceramic casing that holds the CPU is called the package. The silicon wafer that has all the transistors is called the die. Components that are incorporated into the silicon, such as L2 cache memory, are referred to as being **on-die**.
60
address space
The number of wires on the address bus defines the maximum amount of RAM a CPU can theoretically address. This is called the **address space**.
61
pipeline
The term **pipeline** refers to the discrete series of steps that the CPU follows to process commands.
62
clock speed
The CPU **clock speed**, or frequency, tells you how many calculation cycles a CPU can (in theory) execute per second.
63
Hz
One CPU calculation cycle per second is equal to 1 hertz (**Hz**).
64
MHz
millions of calculation cycles per second, or **megahertz** (MHz).
65
GHz
CPU clock speed measured in billions of cycles per second, or **gigahertz** (GHz).
66
system crystal
The system crystal—a quartz crystal circuit that oscillates at a fixed frequency when fed current—**sets the motherboard's clock speed.**
67
CPUID
Today's CPUs actually report to the motherboard through a function called CPUID (**CPU identifier**), and the system bus speed and multiplier are often set automatically.
68
PGA
All current CPUs come in a square package called a **pin grid array** (PGA),
69
BGA
All current CPUs come in a square package called a pin grid array (PGA), but variations exist within and among manufacturers. Collectively, Intel and AMD have used close to 100 variations of the PGA package over the years for hundreds of different CPU models. They've used names such as staggered-PGA, micro-PGA, **ball grid array**, or BGA (which uses tiny balls instead of pins), and land grid array, or LGA (which uses flat pads instead of pins).
70
LGA
All current CPUs come in a square package called a pin grid array (PGA), but variations exist within and among manufacturers. Collectively, Intel and AMD have used close to 100 variations of the PGA package over the years for hundreds of different CPU models. They've used names such as staggered-PGA, micro-PGA, ball grid array, or BGA (which uses tiny balls instead of pins), and **land grid array**, or LGA (which uses flat pads instead of pins).
71
ZIF
To make CPU insertion and removal easier, these sockets—officially called **zero insertion force** (ZIF) sockets—use a small arm on the side of the socket or a cage that fits over the socket to hold the CPU in place. ZIF sockets are easily identified by their squarish shape.
72
SEC
Exam Tip: For a short time, Intel and AMD produced large, rectangular-shaped CPU packages called **single edge cartridges** (SECs) that fit into a slot, kind of like an expansion card. The first was the Intel Pentium II. The SEC is long dead, but it might show up as an incorrect answer on the 801 exam.
73
MMX
Starting with later versions of the Intel Pentium, manufacturers have improved some of the registers inside the CPU, adding specific-use and general-use registers along with special CPU instructions to use them. The first, developed by Intel, were called **multimedia extensions** (MMX); they were 64-bit and borrowed the FPU's registers while in use.
74
Hyper-Threading Technology
Intel introduced Hyper-Threading Technology with the Pentium 4 processor. Hyper-Threading is **Intel's brand name for its implementation of simultaneous multithreading**, which is a way of executing multiple threads simultaneously on a single processor core. For instance, a single-core Intel Pentium 4 with Hyper-Threading looks like two CPUs to the OS.
Exam Tip: Know that Hyper-Threading is a form of simultaneous multithreading used in Intel chips to increase performance on a single processor core.
75
x86
Exam Tip: Processors come in both **32-bit** (x86) and 64-bit (x64) varieties. 64-bit processors can access more memory (RAM) than 32-bit processors. When used in conjunction with 64-bit software, they can improve performance.
76
x64
Exam Tip: Processors come in both 32-bit (x86) and **64-bit** (x64) varieties. 64-bit processors can access more memory (RAM) than 32-bit processors. When used in conjunction with 64-bit software, they can improve performance.
77
throttling
Modern CPUs can **reduce their processing cycles and lower their clock speeds when they reach a certain temperature**, a feature called *throttling*.
78
virtualization
Intel and AMD have built-in support for **running more than one operating system (or virtual machine)** at a time, a process called virtualization. The key issue from a CPU standpoint is that virtualization used to work entirely through software. Programmers had to write a ton of code to enable a CPU that was designed to run one OS at a time to run more than one OS at the same time.
79
IMC
Almost all current microprocessors have an **integrated memory controller** (IMC), moved from the motherboard chip into the CPU to optimize the flow of information into and out from the CPU.
80
heat sink
A heat sink is **a set of metal tines designed to wick heat away from the CPU**.
81
CMOS clear
Most motherboards have a jumper setting called CMOS clear that makes the **CMOS go back to default settings**.
82
SIMM
**Single inline memory modules** (SIMMs) used to be the most common form of memory, but you won't see them on any PCs manufactured in the last decade.
83
DIMM
**Dual inline memory module**s (DIMMs) are the sticks you're most likely to run into these days, including two popular variants used in laptops, MicroDIMMs and small outline DIMMs (SO-DIMMs).
84
SO-DIMM
**small outline DIMM**s
85
RIMM
Technically, the term RIMM doesn't stand for anything, but most techs use it as an acronym for **Rambus inline memory module**.
86
SME
Exam Tip: I know that many techs will shake their heads about this and say they've been mixing RAM packages for years and never had any problems. CompTIA's **subject matter experts** (SMEs) think it's a problem to mix RAM packages, however, so look for a question on the topic, and get it right.
87
SRAM
RAM comes in two forms: **static RAM** (SRAM) and dynamic RAM (DRAM). SRAM is faster than DRAM because it never needs to be refreshed; however, it is also much more expensive. SRAM is, therefore, reserved for special purposes, such as L1, L2, and L3 system cache memory. (These concepts are different from the 'form factor names like SIMM and DIMM. A DIMM can be either SRAM or DRAM.)
88
DRAM
RAM comes in two forms: static RAM (SRAM) and **dynamic RAM** (DRAM). SRAM is faster than DRAM because it never needs to be refreshed; however, it is also much more expensive. SRAM is, therefore, reserved for special purposes, such as L1, L2, and L3 system cache memory. (These concepts are different from the 'form factor names like SIMM and DIMM. A DIMM can be either SRAM or DRAM.)
DRAM is used for system memory and needs to be refreshed every few nanoseconds (ns).
89
wait state
DRAM is used for system memory and needs to be refreshed every few nanoseconds (ns). During this time, it is inaccessible to the CPU. This interval is called a **wait state**. Faster RAM has a shorter wait state.
90
FPM and EDO
Very old computers used *asynchronous RAM*, memory types that ran at a speed independent of the system clock speed. Two types saw extensive use: **fast page mode** (FPM) and **extended data out** (EDO). You could find both types on 72-pin SIMMs, and you could find (rarely) EDO on 168-pin DIMMs.
## Footnote
Exam Tip: You might see FPM or EDO RAM as incorrect answers on the CompTIA A+ exams.
91
SDRAM
**Synchronous dynamic RAM** (SDRAM) delivers data in high-speed bursts. SDRAM runs at the speed of the system bus (thus, synchronously) and is rated according to the highest speed data bus it runs on, such as 66, 100, or 133 MHz.
This type of memory comes in the DIMM, SO-DIMM, and MicroDIMM form factors.
92
(SPD) chip
SDRAM (and more advanced) DIMMs have a **serial presence detect** (SPD) chip that identifies a DIMM's capacity, speed, and latency—the latter being a measurement of how long the RAM takes to respond to the memory controller.
93
latency
SDRAM (and more advanced) DIMMs have a serial presence detect (SPD) chip that identifies a DIMM's capacity, speed, and *latency*—**the latter being a measurement of how long the RAM takes to respond to the memory controller**.
94
RDRAM
Intel announced plans to replace SDRAM with a faster, new type of RAM developed by Rambus, Inc., called **Rambus DRAM**, or simply RDRAM.
Exam Tip: The CompTIA A+ exams refer to RDRAM and RIMMs by the manufacturer's name: RAMBUS memory. Don't be thrown off by this mislabeling.
95
CRIMM
Even quirkier, RDRAM motherboards required that all RIMM slots be populated. Unused slots needed a passive device called a **continuity RIMM** (CRIMM) installed in each slot to enable the RDRAM system to terminate properly.
RDRAM offered dramatic possibilities for high-speed PCs, but it is effectively dead in today's market. You'll see it still on some game consoles.
96
DDR
Many motherboards support **double data rate** (DDR) SDRAM, usually referred to as simply DDR.
97
DDR2
"**double data rate - 2**"
DDR2 succeeded the DDR SDRAM standard. Improvements in DDR2's electrical characteristics enable it to run even faster than DDR while using less power.
DDR2 uses a 240-pin DIMM form factor as well as a 200-pin SO-DIMM or 214-pin MicroDIMM for portable systems.
98
DDR3
"**double data rate - 3**"
DDR2 was the standard for several years, but DDR3 boasts higher speeds, more efficient architecture, and around 30% lower power consumption than DDR2 RAM.
Exam Tip: You should be familiar with the various RAM speeds. (Lesson 5 Chapter 3)
99
ECC
High-end, mission-critical systems often use special parity or **error-correcting code** (ECC) RAM. These types of RAM use special circuitry to detect and, in some cases, correct errors in data.
100
CMOS
**complementary metal-oxide semiconductor** (CMOS) memory chip and setup utility
101
POST
**power-on self test**
During POST, the system BIOS communicates with all essential hardware and, in essence, tells them all to identify themselves.
102
power good wire
You start the process by powering the system on, sending current to the motherboard and drives. Assuming your power supply is in good working order, a special wire on the central processing unit (CPU) called the **power good wire** is charged, telling it to wake up.
103
beep codes
The way that the PC communicates POST errors is through special sound codes called **beep codes** and through text or numeric messages displayed on your monitor.
104
EEPROM
Current motherboards use writable ROM chips such as flash ROM, or, more technically, **electrically erasable programmable read-only memory** (EEPROM).
105
ROM BIOS
Exam Tip: Many techs refer to the **system BIOS** as the ROM BIOS, and the CompTIA A+ certification exams may use either term.
106
volatile memory
There's a big difference between system ROM chips and RAM that you need to appreciate. RAM is called **volatile memory** because RAM stores data only while the PC is powered on. System ROM memory, on the other hand, is non-volatile memory and retains data even when the system is powered off.
107
non-volatile memory
There's a big difference between system ROM chips and RAM that you need to appreciate. RAM is called volatile memory because RAM stores data only while the PC is powered on. **System ROM memory**, on the other hand, is non-volatile memory and retains data even when the system is powered off.
108
flashing the BIOS
Techs refer to **updating system BIOS** as flashing the BIOS.
Exam Tip: The CompTIA A+ 801 exam refers to flashing the BIOS as **installing a firmware upgrade**. Because the BIOS is stored on ROM rather than in RAM, it's less volatile than software, hence the term firmware.
109
UEFI
Many current motherboards ship with an upgraded style of BIOS called **Unified Extensible Firmware Interface** (UEFI).
110
CMOS setup utility
The CMOS setup utility, **stored in the system ROM,** (not on the CMOS chip) enables you to configure important system BIOS settings stored in the CMOS chip, which is a part of the southbridge on most PCs.
111
M.I.T.
You can use **MB Intelligent Tweaker** (M.I.T.) to change the voltage and multiplier settings on the motherboard for the CPU from the defaults.
112
PnP
**Plug and Play** (PnP) is how devices automatically work when you snap them into your PC.
113
PCI
**Peripheral Component Interconnect** (PCI) is a type of slot used for cards.
114
CMOS clear
if you need to access the CMOS and don't have the supervisor CMOS password, you can gain access in a couple of ways. You can use the **CMOS clear jumper**.
115
TPM
The **Trusted Platform Module** (TPM) acts as a secure cryptoprocessor, which is to say that it is a hardware platform for the acceleration of cryptographic functions and the secure storage of associated information.
116
traces
The motherboard contains the **wires**—called traces—that make up the buses of the system.
117
ATX
Exam Tip: The earliest standard motherboard form factor was called AT, for **Advanced Technology**. X?
118
μATX
You'll sometimes see microATX motherboards referred to with the **Greek symbol for micro**, as in μATX.
119
FlexATX
FlexATX motherboards have maximum dimensions of just 9 by 7.5 inches, which makes them **the smallest motherboards in the ATX standard**.
Note: Many techs and websites use the term mini-ATX to refer to motherboards **smaller than a full ATX board**. This is technically incorrect. The specifications for these small boards use only the terms microATX and FlexATX.
120
SFF
chipset maker VIA Technologies created a **small form factor** (SFF) motherboard, the ITX
121
ITX
insy tinsy X ??
Around 2001, chipset maker VIA Technologies **created a small form factor (SFF) motherboard**, the ITX. The ITX itself wasn't a success, but VIA created a number of even smaller form factors that today populate the SFF market: Mini-ITX, Nano-ITX, and Pico-ITX.
122
Northbridge
The Northbridge **chip on traditional Intel-based motherboards** helped the CPU work with RAM. With later motherboards, the CPU took on the role of the memory controller so the Northbridge provided the communication with the video card. Northbridge chips got pretty hot, requiring their own heat-sink and fan assembly.
123
Southbridge
The Southbridge **traditionally handled some expansion devices and mass storage drives**, such as hard drives. Most Southbridge chips didn't need extra cooling, leaving the chip exposed or passively cooled with only a heat sink.
124
MCH
Chipset makers don't always use the terms Northbridge and Southbridge. Chipsets for AMD-based motherboards tend to use these terms, but Intel-based motherboards tend to say **Memory Controller Hub** (MCH) for the Northbridge and I/O Controller Hub (ICH) for the Southbridge.
125
ICH
Chipset makers don't always use the terms Northbridge and Southbridge. Chipsets for AMD-based motherboards tend to use these terms, but Intel-based motherboards tend to say Memory Controller Hub (MCH) for the Northbridge and **I/O Controller Hub** (ICH) for the Southbridge.
126
SoC
The core processor in the iPhone and other smartphones and tablets is called generically a **system-on-a-chip** (SoC). An SoC performs all the functions that used to require discrete chips on a PC
127
expansion slots
Expansion slots have been part of the PC from the very beginning. Way back then, IBM created the PC with an eye to the future; the original IBM PC had **slots built into the motherboard**—called expansion slots—for adding expansion cards and thus new functions to the PC.
128
expansion bus
The **slots and accompanying wires and support chips on the first PC and on the latest and greatest PC** are called the expansion bus.
129
AGP
Shortly after Intel invented PCI, they presented a specialized, video-only version of PCI called the **Accelerated Graphics Port** (AGP).
130
PCI-X
PCI Extended (PCI-X) was an **enhancement to PCI** that was also fully backward compatible in terms of both hardware and software.
131
Mini-PCI
**PCI has even made it into laptops** in the specialty Mini-PCI format. You'll find Mini-PCI in just about every laptop these days. Mini-PCI is designed to use low power and to lie flat—both good features for a laptop expansion slot.
132
hdwwiz.exe
Exam Tip: Don't be surprised to see hdwwiz.exe on the CompTIA A+ exams. **It's the only way to run the Add Hardware Wizard in Windows 7**.
133
ASUS, BIOSTAR, DFI, GIGABYTE, Intel, MSI, and Shuttle
Brands of motherboards.
134
PSU
power supply unit
135
volts
amps
watts
ohms
Pressure = volts (V)
Volume flowing = amperes (A)
Work = watts (W)
Resistance = ohms (Ω)
136
IEC-320
The power supply connects to the power cord (and thus to an electrical outlet) via a standard IEC-320 connector.
The IEC-320 plug has three holes, called hot, neutral, and ground.
137
VOM
volt-ohm meter
138
DMM
You can use a multimeter—often also referred to as a volt-ohm meter (VOM) or **digital multimeter** (DMM)—to measure a number of aspects of electrical current.
139
VAC
AC voltage
140
VDC
DC voltage
141
EMI
electromagnetic interference
142
RFI
radio frequency interference
143
UPS
An **uninterruptible power supply** (UPS) protects your computer (and, more important, your data) in the event of a power sag or power outage.
144
VA
All uninterruptible power supplies are measured in both watts (the true amount of power they supply in the event of a power outage) and in **volt-amps** (VA). Why the two measurements? Here's the scoop.
## Footnote
A UPS provides perfect AC power, moving current smoothly back and forth 60 times a second. The volt-amps rating describes the amount of power the UPS could supply if the connected devices took power from the UPS perfectly.
145
VDC
Note: You'll sometimes see DC voltages abbreviated as VDC for volts of direct current.
146
Molex connector
**A common type of power connection for devices other than modern hard drives** is the Molex connector.
147
soft power
When plugged in, ATX systems have 5 V running to the motherboard. **They're always "on" even when powered down.** The power switch you press to power up the PC isn't a true power switch like the light switch on the wall in your bedroom. The power switch on an ATX system simply tells the computer whether it has been pressed. The BIOS or operating system takes over from there and handles the chore of turning the PC on or off. This is called soft power.
148
SSI
ATX12V 1.3 power supplies worked fine for consumer systems but didn't offer enough power for some server motherboards. To address server needs, an industry group called the **Server System Infrastructure** (SSI) developed a non-ATX standard motherboard and power supply called EPS12V.
149
rail
A rail is a **set of wires (traces) in the power supply circuit board**. A traditional power supply had one rail for each voltage provided, though the only one that concerns us here is the 12-V rail. That's the one that does most of the work on modern systems.
150
OCP
Each rail is monitored by a circuit called an **Over Current Protection** (OCP). The OCP monitors the rail so it can shut the power supply down if too much current goes through the rail. The big difference between single and multiple rails is safety. The OCP in a single rail system monitors all the amperage. In a multiple rail system, the amperage is monitored in smaller chunks.
151
PCIe
Another notable connector is the **auxiliary PCI Express** (PCIe) power connector. Some motherboards add a Molex socket for PCIe, and some video and sound cards come with a Molex socket as well. Higher-end cards have a dedicated 6-pin or 8-pin PCIe power connector.
PCI Express (PCIe) is the latest, fastest, and most popular expansion bus in use today. As its name implies, PCI Express is still PCI, but it uses a point-to-point serial connection instead of PCI's shared parallel communication.
152
harmonics
Visualize the AC current coming from the power company as water in a pipe, smoothly moving back and forth, 60 times a second. A PC's power supply, simply due to the process of changing this AC current into DC current, is like a person sucking on a straw on the end of this pipe. It takes gulps only when **the current is fully pushing or pulling at the top and bottom of each cycle and creating an electrical phenomena—sort of a back pressure—that's called harmonics in the power industry. These harmonics create the humming sound you hear from electrical components.**
153
active PFC
Good PC power supplies come with **active power factor correction** (active PFC), extra circuitry that smoothes out the way the power supply takes power from the power company and eliminates harmonics. Never buy a power supply that does not have active PFC—all power supplies with active PFC will announce it on the box.
154
UART
A traditional serial port consists of two pieces: the physical, 9-pin DB connector and a chip that actually does the conversion between the serial data and parallel data, called the **universal asynchronous receiver/transmitter** (UART) chip. If you want to be completely accurate, the UART is the serial port. The port on the back of a PC is nothing more than a standardized connector that enables different serial devices to use the serial port. The UART holds all of the smarts that make the true serial port.
155
RS-232
RS-232 **is a very old standard that defines everything about serial ports**: how fast they communicate, the language they use, even how the connectors should look. The RS-232 standard specifies that two serial devices must talk to each other in 8-bit chunks of data, but it also allows flexibility in other areas, such as speed and error-checking.
156
HID
Such a device—think keyboard—is a **human interface device** (HID). Devices that follow the HID standard are said to be HID-compliant devices.
157
mA
milliamps
158
IEEE 1394a
IEEE 1394b
**FireWire comes in two speeds**: IEEE 1394a, which runs at 400 Mbps, and IEEE 1394b, which runs at 800 Mbps.
159
GIMP
the popular free image-editing software, **GNU Image Manipulation Program** (otherwise known as GIMP)
160
GIMP
the popular free image-editing software, **GNU Image Manipulation Program** (otherwise known as GIMP)
161
TWAIN
In this case, the scanner uses the traditional TWAIN drivers. TWAIN stands for **Technology Without an Interesting Name**—I'm not making this up!—and has been the default driver type for scanners for a long time.
162
OCR
many scanners offer a feature called **optical character recognition** (OCR), a way to scan a document and have the computer turn the picture into text that you can manipulate by using a word processing program.
163
biometrics
"Biometric identifiers are the **distinctive, measurable characteristics used to label and describe individuals**." The field of biometrics also encompasses a number of security devices, such as door locks and security cameras, that don't really fit into the world of PCs.
Exam Tip: The CompTIA A+ exams have a pretty high opinion of biometric devices, including the ones not in much use outside of movies (like retinal scanners). Look for questions on any of the topics covered above.
164
UPC
Bar code readers are designed to read standard **Universal Product Code** (UPC) bar codes.
165
KVM
A **keyboard, video, mouse** (KVM) switch is a hardware device that most commonly enables multiple computers to be viewed and controlled by a single mouse, keyboard, and screen.
166
SD
Probably the most common removable storage media used in modern digital cameras (and probably your best choice) is the **Secure Digital** (SD) card.
167
CCD
ou should consider the amount of information a particular model of camera or camcorder can capture, which in the digital world is expressed as some number of megapixels. Instead of light-sensitive film, digital cameras and camcorders have one CCD (**charged coupled device**)
168
HDD
Traditional **hard disk drives** (HDDs) store data magnetically onto spinning platters, using a fast-moving actuator arm with read-write heads.
169
head actuator
Exam Tip: You'll see the **platter-reading component of an HDD** mentioned on the exams as a head actuator.
170
SSD
**Solid-state drives** (SSDs) use memory chips to store data, speeding up load times and reducing the possibility of damage.
171
ATA
**Advanced Technologies Attachment** (ATA) drives populate most PCs. Two styles exist: parallel ATA (PATA) and serial ATA (SATA), with the latter replacing the former as the hard drive of choice in most systems.
172
PATA
Advanced Technologies Attachment (ATA) drives populate most PCs. Two styles exist: **parallel ATA** (PATA) and serial ATA (SATA), with the latter replacing the former as the hard drive of choice in most systems.
173
SATA
Advanced Technologies Attachment (ATA) drives populate most PCs. Two styles exist: parallel ATA (PATA) and **serial ATA** (SATA), with the latter replacing the former as the hard drive of choice in most systems.
174
IDE
Techs often refer to ATA drives as **integrated drive electronics** (IDE) or Enhanced IDE (EIDE). CompTIA has adopted the use of the terms specifically for PATA drives.
175
EIDE
Techs often refer to ATA drives as integrated drive electronics (IDE) or **Enhanced IDE** (EIDE). CompTIA has adopted the use of the terms specifically for PATA drives. Read on for more clarification.
176
LBA
Exam Tip: You should know that the technologies that enabled steadily larger drive size are **Logical Block Addressing** (LBA) (up to 8 GB), interrupt 13 (INT 13) extensions (up to 137 GB), and ATA/ATAPI-7 (up to 144 PB).
177
INT 13
Exam Tip: You should know that the technologies that enabled steadily larger drive size are Logical Block Addressing (LBA) (up to 8 GB), **interrupt 13** (INT 13) extensions (up to 137 GB), and ATA/ATAPI-7 (up to 144 PB).
178
eSATA
**External SATA** (eSATA) extends the SATA bus to external devices, as the name implies. The eSATA drives use similar connectors to internal SATA, but they're keyed differently so you can't mistake one for the other.
179
SCSI
Many servers and workstations use the **small computer system interface** (SCSI) technologies for various pieces of core hardware and peripherals, from hard drives to older printers and high-end tape backup machines. SCSI (pronounced, skuzzy) differs from ATA in that SCSI devices connect together in a string of devices called a SCSI chain.
180
SAS
**Serial attached SCSI** (SAS) dumps the chaining and termination issues that plagued earlier forms of SCSI. Plus it uses narrow cabling (like with SATA). No more horrible cabling issues on our servers! And did I mention that SAS is fast? The latest version (as of this writing) pumps out a cool 12 Gbps! Finally, SAS offers great support for large RAID arrays.
## Footnote
You'll definitely find SAS arrays and drives in many modern servers. Sadly, you won't find it on the CompTIA A+ exams.
181
RAID
redundant array of independent (or inexpensive) disks
182
BSoD
Blue Screen of Death
183
MBR
Windows supports two different partitioning methods: the older but more universal **master boot record** (MBR) partitioning scheme and the newer (but proprietary to Microsoft) dynamic storage partitioning scheme. **Microsoft calls a hard drive that uses the MBR partitioning scheme a basic disk** and a drive using the dynamic storage partitioning scheme a dynamic disk.
184
boot sector
Basic disk partitioning creates two very small data structures on a drive, the MBR and a partition table, and stores them on **the first sector of the hard drive**, called the boot sector.
185
Primary partitions
The partition table supports two types of partitions: primary partitions and extended partitions. **Primary partitions are designed to support bootable operating systems.**
186
Extended partitions
All basic disk partition tables support up to four partitions. The partition table supports two types of partitions: primary partitions and extended partitions. Primary partitions are designed to support bootable operating systems. **Extended partitions are not bootable.** A single basic disk may have up to three primary partitions and one extended partition. If your disk does not have an extended partition, it may have up to four primary partitions.
187
FAT
FAT, creates a 16-bit **file allocation table** (FAT)—that's the big spreadsheet.
188
NTFS
Older versions of Windows operated well on FAT- and FAT32-formatted disks, but to get the full benefits of these as well as newer operating systems, you need **New Technology File System** (NTFS). Put simply, NTFS is the way to go in Windows.
189
MFT
NTFS uses an enhanced file allocation table called the **master file table** (MFT) to keep track of the locations of files and folders.
190
EFS
One of the big draws with NTFS is file encryption, the black art of making files unreadable to anybody who doesn't have the right key. You can encrypt a single file, a folder, or a folder full of files. Microsoft calls the encryption utility in NTFS the **encrypting file system** (EFS), but it's simply an aspect of NTFS, not a stand-alone file system.
191
exFAT
The **newer file system**, called exFAT (**sometimes referred to as FAT64**), breaks the 4-GB file-size barrier. It supports files up to 16 exabytes (EB) and a theoretical partition limit of 64 zettabytes (ZB). Microsoft recommends a partition size of up to 512 TB on today's USB flash drives, which should be enough for a while.
192
chkdsk
Many techs run **Error-checking from the command line** using the chkdsk /f command. The /f tells the program to fix any problems discovered.
193
defrag
Fragmentation of clusters can make drive-access times increase dramatically. It's a good idea to **defragment**—or defrag—your drives as part of your monthly maintenance.
194
CAB file
Pre-Vista versions of Windows store all their installation files in a compressed format called CAB (**short for cabinet file**). One CAB file contains many files, and most installation disks have lots of CAB files.
195
DLT
There are a large number of different tape formats, but CompTIA lists only one technology, **Digital Linear Tape** (DLT), in the CompTIA A+ Acronyms list.
196
CDFS
Optical discs use a unique format, generally called **Compact Disc File System** (CDFS), but more accurately known as the **ISO 9660** file system.
197
ISO file
An ISO file is a complete copy--an ISO image, as we say--of an optical-media disc.
198
NAS
external storage devices connecting via Ethernet. Such devices, called **network attached storage** (NAS) boxes, are purpose-built computers that have a narrow set of functions, namely to enable you to store data in a central location over a network.
199
SOHO
External drives have become the go-to choice for **small office/home office** (SOHO) backup solutions
