Name : Vincent Limonty
NIM : 1701310124
1. How Are Various Styles of System Units on Desktop Computers,
Notebook Computers, and Mobile Devices Different?
The system unit is
a case that contains electronic components of the computer used to process
data. System units are available in a variety of shapes and sizes. The case of
the system unit, sometimes called the chassis, is made of metal or
plastic and protects the internal electronic components from damage. All
computers and mobile devices have a system unit . On desktop personal
computers, the electronic components and most storage devices are part of the
system unit. Other devices, such as the keyboard, mouse, microphone, monitor,
printer, USB flash drive, scanner, Web cam, and speakers normally occupy space
outside the system unit. An all-in-one desktop personal computer is an
exception, which houses the monitor and the system unit in the same case. The
trend is toward a smaller form
factor, or size and shape, of
the desktop personal computer system unit. On most notebook computers,
including netbooks, the keyboard and pointing device often occupy the area on
the top of the system unit, and the display attaches to the system unit by
hinges. The location of the system unit on a Tablet PC varies, depending on the
design of the Tablet PC. With the slate Tablet PC , which typically does not
include a keyboard, the system unit is behind the display. On a convertible
Tablet PC , by contrast, the system unit is positioned below a keyboard,
providing functionality similar to a traditional notebook computer or netbook.
The difference is the display attaches to the system unit with a swivel-type
hinge, which enables a user to rotate the display and fold it down over the
keyboard to look like a slate Tablet PC. The system unit on an Ultra-Mobile PC,
a smart phone, and a PDA usually consumes the entire device. On these mobile
computers and devices, the display often is built into the system unit. With game consoles, the input and output devices, such
as controllers and a television, reside outside the system unit. On handheld
game consoles, portable media players, and digital cameras, by contrast, the
packaging around the system unit houses the input devices and display.
2. What Are Chips, Adapter Cards, and Other Components of
the Motherboard?
The motherboard, sometimes called a system
board, is the main circuit board of the
system unit. Many electronic components attach to the motherboard; others are
built into it. The motherboard contains many electronic components including a
processor chip, memory chips, expansion slots, and adapter cards. Memory chips
are installed on memory cards (modules) that fit in a slot on the motherboard.
A computer chip is a small piece of semiconducting material, usually
silicon, on which integrated circuits are etched. Expansion slots hold adapter
cards that provide connections and functions not built into the motherboard. An
integrated circuit contains many microscopic pathways capable of carrying
electrical current. Each integrated circuit can contain millions of elements
such as resistors, capacitors, and transistors. A transistor,
for example, can act as an electronic switch that opens or closes the circuit
for electrical charges. Today’s computer chips contain millions or billions of
transistors. Most chips are no bigger than one-half-inch square. Manufacturers
package chips so that the chips can be attached to a circuit board, such as a
motherboard or an adapter card.
3. What Are the Control Unit and Arithmetic Logic Unit
Components of a Processor, and What Are the Four Steps in a Machine Cycle?
The processor, also called the central
processing unit (CPU), interprets and carries out the basic instructions
that operate a computer. The processor significantly impacts overall computing
power and manages most of a computer’s operations. Processors contain a control
unit and an arithmetic logic unit (ALU). These two components work together to
perform processing operations. The control unit is
the component of the processor that directs and coordinates most of the operations
in the computer. The control unit has a role much like a traffic cop: it
interprets each instruction issued by a program and then initiates the
appropriate action to carry out the instruction. Types of internal components
that the control unit directs include the arithmetic/logic unit, registers, and
buses. The arithmetic logic unit (ALU), another component of the processor, performs
arithmetic, comparison, and other operations. Arithmetic
operations include basic calculations such as
addition, subtraction, multiplication, and division. Comparison operations involve comparing one data item with another to
determine whether the first item is greater than, equal to, or less than the
other item. Depending on the result of the comparison, different actions may
occur.
For every instruction, a processor repeats a set of four
basic operations, which comprise a machine
cycle (Figure 4-5): (1) fetching, (2)
decoding, (3) executing, and, if necessary, (4) storing. Fetching is
the process of obtaining a program instruction or data item from memory. The
term decoding refers to the process of translating the instruction
into signals the computer can execute. Executing
is the process of carrying out the
commands. Storing, in this context, means writing the result to memory
(not to a storage medium).
4.
What Are the
Characteristics of Various Personal Computer Processors, and How Are Processors
Cooled?
A processor core, or simply core, contains the circuitry
necessary to execute instructions. The operating system views each processor core
as a separate processor. A multi-core processor
is a single chip with two or more
separate processor cores. Two common multi-core processors are dual-core and
quad-core. A dual-core processor is a chip that contains two separate processor cores.
Similarly, a quad-core processor is a chip with four separate processor cores. The
leading manufacturers of personal
computer processor chips are Intel and AMD. These
manufacturers often identify their processor chips by a model name or model
number. High-performance personal computers today may use a processor in the
Intel Core family. Less expensive, basic personal computers may use
a brand of Intel processor in the Pentium
or Celeron family.
The Xeon and Itanium families of processors are ideal for workstations and
low-end servers. AMD is the leading manufacturer of Intel compatible processors, which have an internal design similar to Intel
processors, perform the same functions, and can be as powerful, but often are
less expensive.
In the past, chip manufacturers listed a processor’s
clock speed in marketing literature and advertisements. As previously
mentioned, though, clock speed is only one factor that impacts processing speed
in today’s computers. To help consumers evaluate various processors,
manufacturers such as Intel and AMD now use a numbering scheme that more
accurately reflects the processing speed of their chips. Processor chips
include technologies to improve processing performance, for example, to improve
performance of multimedia and 3-D graphics. Most of Intel’s processor chips
also include vPro technology, which provides the capability to track computer
hardware and software, diagnose and resolve computer problems, and secure
computers from outside threats. As mentioned earlier, many personal computer
processors are multi-core, with the processor cores working simultaneously on
related instructions. These related instructions, called a thread, can be
independent or part of a larger task. Software written to support multiple
threads, called a multi-threaded program, runs much faster than those in non threaded
environments. Processors for traditional notebook computers and Tablet PCs also
include technology to optimize and extend battery life, enhance security, and integrate
wireless capabilities. For example, Intel’s Centrino
2 mobile technology, which may have a
Pro designator depending on its capabilities, integrates wireless functionality
in notebook computers and Tablet PCs. Netbooks, smart phones, and other smaller
mobile devices often use more compact processors that consume less power, yet
offer high performance. Another type of processor, called system-on a- chip,
integrates the functions of a processor, memory, and a video card on a single
chip. Lower-priced personal computers, Tablet PCs, networking devices, portable
media players, and game consoles sometimes have a system on- a-chip processor.
The goal of system-on-a chip manufacturers is to create processors that have
faster clock speeds, consume less power, are small, and are cost effective.
Processor chips generate quite a bit of heat, which
could cause the chip to burn up. Although the computer’s main fan generates
airflow, many of today’s personal computer processors require additional
cooling. Heat sinks/ pipes and liquid cooling technologies often are used to
help dissipate processor heat.
A heat sink is a small ceramic or metal component with fins on its
surface that absorbs and disperses heat produced by electrical components such
as a processor (Figure 4-9). Some heat sinks are packaged as part of a
processor chip. Others are installed on the top or the side of the chip.
Because a heat sink consumes extra space, a smaller device called a heat pipe cools
processors in notebook computers, including netbooks and Tablet PCs.
Some computers use liquid cooling technology to reduce
the temperature of a processor. Liquid
cooling technology uses a continuous flow of fluid(s),
such as water and glycol, in a process that transfers the heated fluid away
from the processor to a radiator-type grill, which cools the liquid, and then
returns the cooled fluid to the processor .
Some mobile computers and devices often have Low Voltage
or Ultra Low Voltage (ULV) processors, which have such low power demands that
they do not require additional cooling.
5.
What Is a Bit,
and How Does a Series of Bits Represent Data?
The computer, by contrast, uses a binary system because
it recognizes only two states. The binary
system is a number system that has just
two unique digits, 0 and 1, called bits. A bit
(short for binary digit)
is the smallest unit of data the computer can process. By itself, a bit is not
very informative. When 8 bits are grouped together as a unit, they form a byte. A byte
provides enough different combinations of 0s and 1s to represent 256 individual
characters. These characters include numbers, uppercase and lowercase letters
of the alphabet, punctuation marks, and others, such as the letters of the
Greek alphabet. The combinations of 0s and 1s that represent characters are
defined by patterns called a coding scheme. In one coding scheme, the number 4
is represented as 00110100, the number 6 as 00110110, and the capital letter E
as 01000101. ASCII (pronounced ASK-ee), which stands for American Standard
Code for Information Interchange, is the most widely used coding scheme to
represent data. Coding schemes make it possible for humans to interact with a
digital computer that processes only bits.
6.
How Do Program
Instructions Transfer in and out of Memory?
When a program starts, the program’s instructions
and data are transferred to memory from storage devices. The program and
operating system instructions are in memory, and the program’s window appears
on the screen. When you quit the program, the program instructions are removed
from memory, and the program no longer is displayed on the screen.
7.
What Are the
Various Types of Memory?
The system unit contains two types of memory: volatile
and nonvolatile. When the computer’s power is turned off, volatile memory loses
its contents. Nonvolatile memory, by contrast, does not lose its contents when power is
removed from the computer. Thus, volatile memory is temporary and nonvolatile
memory is permanent. RAM is the most common type of volatile memory. Examples
of nonvolatile memory include ROM, flash memory, and CMOS.
RAM (random access memory),
also called main memory, consists of memory chips that can be read from and
written to by the processor and other devices. When you turn on power to a computer,
certain operating system files (such as the files that determine how the
desktop appears) load into RAM from a storage device such as a hard disk. These
files remain in RAM as long as the computer has continuous power. As additional
programs and data are requested, they also load into RAM from storage.
Most of today’s computers improve their processing times
with cache (pronounced cash). Two types of cache are memory cache
and disk cache. Memory cache helps speed the processes of the computer because it
stores frequently used instructions and data. Most personal computers today
have two types of memory cache: L1 cache and L2 cache. Some also have L3 cache.
Read-only memory (ROM pronounced
rahm) refers to memory chips storing permanent data and instructions. The data
on most ROM chips cannot be modified — hence, the name read-only. ROM is
nonvolatile, which means its contents are not lost when power is removed from
the computer. In addition to computers, many devices contain ROM chips. For
example, ROM chips in printers contain data for fonts.
Flash memory is
a type of nonvolatile memory that can be erased electronically and rewritten,
similar to EEPROM. Most computers use flash memory to hold their startup
instructions because it allows the computer easily to update its contents.
Some RAM chips, flash memory chips, and other memory
chips use complementary metal-oxide
semiconductor (CMOS
pronounced SEE-moss) technology
because it provides high speeds and consumes little power. CMOS technology uses
battery power to retain information even when the power to the computer is off.
Battery-backed CMOS memory chips, for example, can keep the calendar, date, and
time current even when the computer is off. The flash memory chips that store a
computer’s startup information often use CMOS technology.
Access time is
the amount of time it takes the processor to read data, instructions, and
information from memory. A computer’s access time directly affects how fast the
computer processes data. Accessing data in memory can be more than 200,000
times faster than accessing data on a hard disk because of the mechanical
motion of the hard disk.
8.
What Are the
Purpose and Types of Expansion Slots and Adapter Cards, and What Are the
Different Slots for Flash Memory Devices?
An expansion slot is a socket on the motherboard that can hold an adapter
card. An adapter card, sometimes called an expansion
card, is a circuit board that enhances
functions of a component of the system unit and/or provides a connection to a peripheral.
A sound card enhances the sound-generating capabilities of a personal
computer. A video card, also called a graphics
card, converts computer output into a
video signal that displays an image on the screen. A memory card is
a removable fl ash memory device that you insert and remove from a slot in a
personal computer, a game console, a mobile device, or card reader/writer. A USB flash drive plugs
in a USB port on a computer or mobile device. A PC Card slot or
an ExpressCard slot holds a PC
Card or ExpressCard module.
9.
What Is the
Difference between a Port and a Connector, and What Are the Differences among
the Various Types of Ports?
A port is the point at which a peripheral attaches to or
communicates with a system unit so that the peripheral can send data to or
receive information from the computer. An external device, such as a keyboard,
monitor, printer, mouse, and microphone, often attaches by a cable to a port on
the system unit. Instead of port, the term jack
sometimes is used to identify audio
and video ports. The front and back of a system unit on a desktop personal
computer contain many ports.
A connector joins a cable to a port. A connector at one end of a
cable attaches to a port on the system unit, and a connector at the other end
of the cable attaches to a port on the peripheral. Most connectors and ports
are available in one of two genders: male or female. Male connectors and ports
have one or more exposed pins, like the end of an electrical cord you plug in
the wall. Female connectors and ports have matching holes to accept the pins on
a male connector or port, like an electrical wall outlet.
A USB port, short for universal
serial bus port, can connect up to 127 different
peripherals together with a single con nector. A FireWire port can
connect multiple types of devices that require faster data transmission speeds.
Bluetooth technology uses radio waves to transfer data between two
devices. A SCSI port attaches the system unit to SCSI peripherals, such as
disk drives and printers. An eSATA
port connects an external SATA hard disk
to a computer. An IrDA port allows wireless devices to transmit signals to a
computer via infrared light waves. A serial
port transmits data one bit at a time. A
MIDI port connects the system unit to a musical instrument.
10. What Are the Types of Buses in a Computer?
Buses are used to transfer bits from input devices to
memory, from memory to the processor, from the processor to memory, and from memory
to output or storage devices. Buses consist of two parts: a data bus and an
address bus. The data bus is used to transfer actual data and the address bus is
used to transfer information about where the data should reside in
memory. A computer has these basic types of buses: a
system bus, possibly a backside bus, and an expansion bus. A system bus,
also called the front side bus ( FSB), is part of the motherboard and connects the processor to
main memory. A backside bus ( BSB) connects the processor to cache. An expansion bus allows
the processor to communicate with peripherals. When computer professionals use
the term bus by itself, they usually are referring to the system bus.
The types of expansion buses : PCI bus, PCI Express bus,
AGP bus, USB, FireWire bus, and PC Card bus.
• The PCI
bus (Peripheral Component Interconnect
bus) is a high-speed expansion bus that connects higher speed devices. Types of
cards you can insert in a PCI bus expansion slot include video cards, sound
cards, SCSI cards, and high-speed network cards.
• The PCI
Express (PCIe) bus is an expansion bus that expands on and doubles the
speed of the original PCI bus. Nearly all video cards today use the PCI Express
bus, as well as many hard disks and network cards. The ExpressCard technology
used in traditional notebook computers and Tablet PCs also works with the PCI
Express bus. Experts predict the PCI Express bus eventually will replace the
PCI bus completely.
• The Accelerated
Graphics Port (AGP) is a bus designed by Intel to improve the speed with
which 3-D graphics and video transmit. With an AGP video card in an AGP bus
slot, the AGP bus provides a faster, dedicated interface between the video card
and memory. Newer processors support AGP technology.
• The USB (universal serial bus) and FireWire bus are
buses that eliminate the need to install cards in expansion slots. In a
computer with a USB, for example, USB devices connect to each other outside the
system unit, and then a single cable attaches to the USB port. The USB port
then connects to the USB, which connects to the PCI bus on the motherboard. The
FireWire bus works in a similar fashion. With these buses, expansion slots are
available for devices not compatible with USB or FireWire.
•The expansion bus for a PC Card is the PC Card bus.
With a PC Card inserted in a PC Card slot, data travels on the PC Card bus to
the PCI bus.
11. What Is the Purpose of a Power Supply, and How Does It
Keep Cool?
The power supply is the component of the system unit that converts the
wall outlet AC power into DC power. Different motherboards and computers
require different wattages on the power supply. Notebook computers, including
netbooks and Tablet PCs, can run using either batteries or a power supply. If a
power supply is not providing the necessary power, the computer will not
function properly. Built into the power supply is a fan that keeps the power
supply cool. Some have variable speed fans that change speed or stop running,
depending on temperature in the system unit. Many newer computers have
additional fans near certain components in the system unit such as the
processor, hard disk, and ports. Some users install more fans to help dissipate
heat generated by the components of the system unit. Mobile users may place
their notebook computer on a cooling pad to help disperse the computer’s heat.
12. How Do You Clean a System Unit on a Personal Computer or
Mobile Device?
Before cleaning the exterior of a computer or mobile
device, turn it off, and if necessary, unplug it from the electrical outlet,
remove the battery, and disconnect all cables from the ports. Use compressed
air to blow away dirt from any openings on the case, such as drives, slots,
ports, and fan vents. Use an antistatic wipe to clean the exterior of the case
and a cleaning solution on a soft cloth to clean the screen. While working
inside the case, be sure to wear an antistatic wristband. If you do not feel
comfortable cleaning the inside of the case, you can have a professional or
computer company clean it for you. Use a vacuum and compressed air to remove
dust inside the case.
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