4
Chapter Topics
• UNIT 4A: Processing: The System Unit, Microprocessors, & Main Memory
4.1 Microchips, Miniaturization, & Mobility
What are the differences between transistors, integrated circuits, chips, and microprocessors?
4.2 Representing Data Electronically
How is data represented in a computer, and what is machine language?
4.3 Inside the System Unit: Power Supply, Motherboard, & Microprocessors
What are the important components of the system unit?
4.4 The Central Processing Unit & the Machine Cycle
What are the parts of the CPU, and how do they work in the machine cycle?
4.5 Memory
How do RAM, ROM, CMOS, and flash differ?
4.6 Expansion Cards, Bus Lines, & Ports
How do expansion cards, bus lines, and ports give computers more versatility?
• UNIT 4B: Secondary Storage
4.7 Secondary Storage
What are the features of hard disks, optical disks, flash memory, smart cards, and cloud storage?
4.8 Future Developments in Processing & Storage
What are some forthcoming developments that could affect processing power and storage capacity?
2
MICROCHIPS, MINIATURIZATION, & MOBILITY
• The lightbulb-
size 1940s
vacuum tube
was replaced in
the 1950s by a
transistor onehundredth its
size.
• Many of today’s
transistors are
much smaller,
being
microscopic in
size.
Transistors
Vacuum tube
Typical transistors for a computer circuit board
MICROCHIPS, MINIATURIZATION, & MOBILITY
• Transistor
• A tiny electrically operated switch, or gate,
that can alternate between “on” and “off”
many millions of times per second.
• Integrated circuit
• An entire electronic circuit, including wires,
formed on a single “chip,” or piece, of
special material, usually silicon, as part of
a single manufacturing process.
• Embodies solid-state technology
• In a solid-state device , the electrons travel
through solid material with no moving parts —
in this case, silicon.
MICROCHIPS, MINIATURIZATION, & MOBILITY
• Silicon
• An element that is widely found in clay and sand. It is used not only because its
abundance makes it cheap but also because it is a semiconductor.
• Semiconductor
• A material whose electrical properties are intermediate between a good
conductor of electricity and a nonconductor of electricity.
• Chip (microchip)
• A tiny piece of silicon that contains millions of microminiature etched integrated
electronic circuits.
• Microprocessor (“microscopic processor”) or (“processor on a chip”)
• The miniaturized circuitry of a computer processor—the CPU (central processing
unit)
Microprocessors and microcontrollers have enabled mobility of electronic
devices.
REPRESENTING DATA ELECTRONICALLY
• Binary System
• The basic datarepresentation method for
computers.
• uses just two numbers: 0 and
1, representing the off/on
states of electricity or light
pulses.
REPRESENTING DATA ELECTRONICALLY
MEASURING CAPACITY
• Bit: In the binary system, each 0 or 1 is called a bit , which is short for
“binary digit.”
• Byte: To represent letters, numbers, or special characters (such as ! or
*), bits are combined into groups. A group of 8 bits is called a byte ,
and a byte represents one character, digit, or other value. (As we
mentioned, in one scheme, 01000111 represents the letter “G.”)
• Kilobyte: A kilobyte (K, KB) is about 1,000 bytes. (Actually, it’s
precisely 1,024 bytes.)
• The kilobyte was a common unit of measure for memory or secondary-storage
capacity on older computers.
• Megabyte: A megabyte (“meg”; M, MB) is about 1 million bytes
(1,048,576 bytes).
• Measures of some secondary-storage devices are expressed in megabytes.
REPRESENTING DATA ELECTRONICALLY
• Gigabyte: A gigabyte (“gig”; G, GB) is about 1 billion bytes (1,073,741,824
bytes). 1 GB = about 786,432 pages of text; 20 GB 5 an audio collection of
the complete works of Beethoven.
• Terabyte: A terabyte (T, TB) represents about 1 trillion bytes
(1,009,511,627,776 bytes). 1 TB 5 about 500,000,000 pages of text; 2 TB =
the contents of 1 academic research library. As of May 2013, the U.S.
Library of Congress has collected about 422 TB of web archive data. The
web archives grow at a rate of about 5 TB per month.
• Petabyte: A petabyte (P, PB) represents about 1 quadrillion bytes (1,048,576
gigabytes). 2 PB 5 about the contents of all U.S. academic research libraries.
The huge storage capacities of modern databases are expressed in
petabytes; Google data centers process more than 24 PB per day.
• Exabyte: An exabyte (EB) represents about 1 quintillion bytes —that’s 1 billion
billion bytes (1,024 petabytes—or 1,152,921,504,606,846,976 bytes).
Google’s servers contain about 1 EB of data.
REPRESENTING DATA ELECTRONICALLY
• BINARY CODING SCHEMES
• Letters, numbers, and special characters are
represented within a computer system by means of
binary coding schemes
• ASCII: (American Standard Code for Information
Interchange)
• The binary code most widely used on microcomputers in
English and Western European languages.
• Uses 8 bits (1 byte) for each character.
• Unicode:
• Uses 2 bytes for each character, rather than 1 byte.
Instead of having the 256 character combinations of
Extended ASCII
• Can handle 65,536 character combinations.
• EBCDIC: (Extended Binary Coded Decimal Interchange Code)
• A binary code used with large IBM and IBM-compatible
computers, such as mainframes.
INSIDE THE SYSTEM UNIT: Power Supply,
Motherboard, & Microprocessors
• System unit
• A case that contains the computer’s electronic components used to
process data.
• Houses the power supply; the motherboard, with its microprocessor
chip and memory chips; and storage devices.
• Power Supply
• Provides power for the motherboard and other main components of
the computer.
• Surge Protector
• A device that protects a computer from being damaged by surges
(spikes) of high voltage.
Surge protector
• UPS (uninterruptible power supply)
• A battery-operated device that provides a computer with electricity if
there is a power failure.
• The UPS will keep a computer going for 5–30 minutes or more.
UPS
INSIDE THE SYSTEM UNIT: Power Supply,
Motherboard, & Microprocessors
The system unit for a
tower PC
Interior view of the box,
or case. It includes the
power supply,
motherboard,
and storage
devices. (The
arrangement
of the components
varies among models.)
INSIDE THE SYSTEM UNIT: Power Supply,
Motherboard, & Microprocessors
Motherboard, or system
board
•
•
•
•
•
Expansion is a way of increasing a computer’s capabilities by adding hardware to perform tasks that
are beyond the scope of the basic system
Upgrading means changing to newer, usually more powerful or sophisticated versions, such as a
more powerful microprocessor or more memory chips.
The main circuit board
in the system unit.
Consists of a flat board
that fills one side of the
case.
Contains both soldered,
nonremovable
components and
sockets or slots for
components that can
be removed—
microprocessor chip,
RAM chips, and various
expansion cards
INSIDE THE SYSTEM UNIT: Power Supply,
Motherboard, & Microprocessors
• Chipset
• Chips for controlling
information among system
components:
• Consists of groups of
interconnected chips on the
motherboard that are designed
to work together to control the
flow of information between
the microprocessor and other
system components connected
to the motherboard
INSIDE THE SYSTEM UNIT: Power Supply,
Motherboard, & Microprocessors
COMMON MULTICORE PROCESSORS FOR MICROCOMPUTERS
• DUAL-CORE PROCESSORS (two cores—for example, AMD
phenom II X2, intel core duo),
• QUAD-CORE PROCESSORS (four cores—for instance, AMD
phenom II X4 and the intel “bay trail” atom processor)
• HEXA-CORE PROCESSORS (six cores—for example, AMD
phenom II X6, intel core i7 extreme edition 980X)
• OCTA-CORE PROCESSORS (eight cores— for example, AMD
opteron 6100 series 6128, Intel Xeon E5-2450).
INSIDE THE SYSTEM UNIT: Power Supply,
Motherboard, & Microprocessors
• GRAPHICS PROCESSING UNITS
• Specialized processors for 3-D graphics
• A specialized processor used to manipulate three-dimensional (3D) computer graphics.
• Able to perform a range of complex algorithms (problem-solving
steps).
INSIDE THE SYSTEM UNIT: Power Supply,
Motherboard, & Microprocessors
• Processing Speeds
• Every microprocessor contains a system clock, which controls how
fast all the operations within a computer take place (the chip’s
processing speed).
• Older CPU processing speeds are in megahertz
• 1 MHz = 1 million operations per second
• Current CPU processing speeds are in gigahertz
• 1 GHz = 1 billion operations per second
• The faster a CPU runs, the more power it consumes, and the more
heat it generates
THE CENTRAL PROCESSING
UNIT & THE MACHINE CYCLE
• CPU
• The “brain” of the computer
• Follows the instructions of the software
(program) to manipulate data into
information.
• Consists of two parts:
(1) control unit
(2) arithmetic/logic unit (ALU)
Both uses registers.
Each time the central processing unit executes an
instruction, it takes a series of steps. The complete
series of steps is called a machine cycle.
THE CENTRAL PROCESSING UNIT & THE MACHINE
CYCLE
• Control Unit
• Deciphers each instruction stored in the CPU and then carries out the
instruction.
• Arithmetic/Logic Unit (ALU)
• Performs arithmetic operations and logical operations and controls the
speed of those operations.
• Registers
• High-speed storage areas that temporarily store data during processing.
• Buses, or Bus Lines
• Electrical data roadways through which bits are transmitted within the CPU and
between the CPU and other components of the motherboard.
MEMORY
• Two type of storage:
• Primary storage = “memory,” “main memory,” “RAM”; this type of memory is
temporary and volatile
• Secondary storage = “storage” disks and flash memory units; this type of
memory is relatively permanent and nonvolatile
MEMORY
Four principal types of memory chips
1.
RAM (random access memory)
•
•
2.
ROM (read-only memory)
•
•
•
3.
Nonvolatile memory
Cannot be written on or erased by the computer user without special equipment.
Loaded at factory with fixed (permanent) start-up instructions (BIOS), that tell the computer how to load the operating
system
Flash Memory
•
•
•
4.
Volatile memory
Temporarily hold software instructions and data before and after it is processed by the CPU.
Nonvolatile memory
can be erased and reprogrammed more than once
doesn’t require a battery and which can range from 2 gigabytes to 256 gigabytes in capacity
CMOS (complementary metal-oxide semiconductor)
•
•
•
Nonvolatile memory
Contain flexible start-up instructions—such as time, date, and calendar—that must be kept current even when the computer
is turned off
Powered by a battery
MEMORY
TYPES OF RAM
• DRAM (dynamic RAM)
• must be constantly refreshed by the CPU or it will lose its
contents.
• Faster variations:
• SDRAM (synchronous dynamic RAM), which is synchronized by the system
clock
• DDR-SDRAM (double-data rate synchronous dynamic RAM) and its later
variations DDR2 and DDR3
• RDRAM (Rambus DRAM), which is much faster than SDRAM.
• SRAM (static RAM)
• Faster than DRAM and retains its contents without having to be
refreshed by the CPU.
• MRAM (magnetoresistive RAM)
• stores data using magnetic charges rather than electric charges
and is faster and stores more data than electronic RAM.
• retains its contents when the power is shut off.
MEMORY
• Speeding up Processing: Cache
• The CPU works much faster than
RAM, so it often must wait for
information
• Cache temporarily stores instructions
and data that the processor uses
frequently to speed up processing
22
Expansion Cards, Bus Lines, & Ports
Expansion cards plug into slots on the motherboard that are connected by buses
to ports that the user can access.
• Closed architecture
• has no expansion slots
• design specifications are not made freely available by the
manufacturer
• Open architecture
• have expansion slots.
• the manufacturer shares specifications with outsiders
Expansion Cards, Bus Lines, & Ports
• Expansion slots
• Sockets on the motherboard into which
you can plug expansion cards.
• Expansion cards
• Also known as expansion boards, adapter
cards, interface cards, plug-in boards,
controller cards, add-ins, or add-ons
• Circuit boards that provide more memory
or that control peripheral devices.
• Plug and Play
• a set of hardware and software standards
that allow the computer to automatically
configure expansion cards and other
peripherals while they are being installed.
Expansion Cards, Bus Lines, & Ports
• Types of Expansion Cards
• Graphics cards (for monitors)
• Also called a video card, video RAM (VRAM), or video adapter
• Converts signals from computer into video signals that can be displayed as images on a monitor
• Sound cards (for speakers and audio output)
• Used to convert and transmit digital sounds through analog speakers, microphones, and
headsets
• Network interface cards (for remote communication via cable)
• Allows the transmission of data over a cabled (wired) network, which connects various
computers and other devices such as printers.
• Wireless network cards (for through-the-air connections)
• Enables wireless data transmission.
• PC Cards or ExpressCards (primarily for wireless Internet access)
• are thin, credit-card-size reusable (flash) memory devices used on traditional and notebook
computers and tablets to expand capabilities, such as to access the Internet wirelessly
Expansion Cards, Bus Lines, & Ports
• Buses Or Bus Lines
• Electric data roadways through
which bits are transmitted
• Every bus deals with a
particular kind of traffic.
Two types:
1. Frontside bus
• bus that connects the CPU
within itself and to main
memory
• also called the system bus or
memory.
2.
Expansion bus:
• buses that connect the CPU
with expansion slots on the
motherboard and thus with
peripheral devices
Expansion Cards, Bus Lines, & Ports
COMMON EXPANSION BUSES FOUND IN PERSONAL COMPUTERS
1.
PCI BUS: FOR HIGH-SPEED CONNECTIONS
•
•
2.
PCI EXPRESS BUS: FOR DOUBLING THE SPEED
•
•
•
3.
4.
5.
32 or 64 bits wide
high-speed bus that has been widely used to connect PC graphics cards, sound cards, modems, and highspeed network cards.
doubles the speed of the original PCI bus .
latest standard for expansion cards available on mainstream personal computers.
Also used in a variety of formats, including Express Card.
THE ACCELERATED GRAPHICS PORT BUS: FOR 3-D GRAPHICS Because the PCI
•
transmits data at twice the speed of a PCI bus and is designed to support video and 3-D graphics.
•
•
Does not require to install cards in expansion slots.
USB devices can connect one to another outside the system unit, and then the USB bus connects to the
PCI bus on the motherboard.
THE UNIVERSAL SERIAL BUS: FOR ELIMINATING THE NEED FOR EXPANSION CARDS IN
SLOTS
FIREWIRE BUS: FOR CONNECTING AUDIO & VIDEO DEVICES
•
resembles the USB bus, but is used for more specialized purposes, such as to connect audio and video
equipment to the motherboard
Expansion Cards, Bus Lines, & Ports
Port
• a connecting socket or jack on
the outside of the computer
unit or device into which are
plugged different kinds of
cables
• used to connect peripheral
devices
Expansion Cards, Bus Lines, & Ports
• DEDICATED PORTS—FOR KEYBOARD, MOUSE, MONITOR,
AUDIO, & MODEM/ NETWORK CONNECTION
• Ports for special purposes, such as the ports for connecting the
keyboard and the mouse, the monitor port, the audio ports (green for
speakers or headphones, pink for microphone, yellow for home stereo
connection), the modem port to connect your computer to a phone
line, and a network port for a high-speed Internet connection.
• STANDARD PORTS—FOR USB, FIREWIRE, ETHERNET, &
GRAPHICS
• USB ports—the most widely used connection for peripherals:
• high-speed hardware standard for interfacing peripheral devices, such as
scanners and printers, to computers without a need for special expansion
cards or other hardware modifications to the computer.
• multipurpose, useful for all kinds of peripherals, and are included on all of
today’s microcomputers.
Expansion Cards, Bus Lines, & Ports
• FireWire ports—for connecting devices with lots
of data:
• preceded the USB port and had similar goals.
• intended for multiple devices working with lots of
data and requiring fast transmission speeds, such
as DVD drives, digital video cameras, and gaming
consoles.
• can connect up to 63 peripheral FireWire devices to
a single FireWire port
• Ethernet ports—for wired network connection:
• supports a network standard for linking a wired
local area network and connecting it to a DSL or a
cable modem for high-speed Internet access.
Expansion Cards, Bus Lines, & Ports
• Graphics ports—for connecting monitors and
multimedia devices:
• DVI (Digital Video Interface) ports for connecting digital
monitors and multimedia digital devices, such as TVs and
DVD players.
• VGA (Video Graphics Adapter) ports for connecting analog
monitors.
Expansion Cards, Bus Lines, & Ports
• OTHER PORTS—SERIAL, PARALLEL, eSATA,
BLUETOOTH, IrDA, HDMI, & MIDI
• Serial ports—for transmitting slow data over long
distances
• Send bits one at a time, one after another
• Parallel ports—for transmitting fast data over data over
short distances:
• allows 8 bits (1 byte) to be transmitted simultaneously
• eSATA (Serial Advanced Technology Attachment)
ports—for connecting fast external hard disks
• allows the attachment of an eSATA hard disk, which has
fast data transmission speeds.
Expansion Cards, Bus Lines, & Ports
• OTHER PORTS—SERIAL, PARALLEL, eSATA, BLUETOOTH, IrDA,
HDMI, & MIDI
• Bluetooth ports—for wireless connections up to 30 feet
• allow you to connect technology that uses shortrange radio waves that transmit
up to 30 feet.
• used to connect Bluetooth-enabled cellphones to computers
• IrDA (Infrared Data Association ) ports—for transmitting data via
infrared light waves
• transfer data via infrared light waves between directly aligned devices, as
between a smartphone and a desktop computer.
• HDMI (High-Definition Multimedia Interface ) ports—for high-definition
video and audio
• can carry both video and audio signals and are used for connecting HDTVs, DVD
players, and game consoles to computers, laptops, and other devices.
• MIDI (Short for Musical Instrument Digital Interface) ports—for
connecting electronic musical instruments
• used to connect electronic musical instruments to a sound card that converts
the signals to digital instructions that can be saved or manipulated.
Secondary Storage
TYPES OF SECONDARY STORAGE
1. Hard disks
• Thin, rigid metal, glass, or ceramic platters covered with a substance that
allows data to be held in the form of magnetized spots
•
•
•
•
The more platters there are, the higher the drive capacity
Store data in tracks, sectors, and clusters
Formatting creates a file allocation table that maps files to clusters.
Important data should always be backed up!
2. Optical Disks
• CDs (compact disks) and DVDs (digital versatile/video disks) are optical
disks
• Data is written and read using lasers, not a disk read/write head
• CD-ROM is Compact Disk Read-Only Memory
• CD-R (compact disk-recordable) is used for recording only once
• CD-RW (compact disk-rewritable)is an erasable optical disk that can both
record and erase data over and over again
• Blu-ray is an optical-disk format used to record, rewrite, and play back highdefinition (HD) video, as well as to store large amounts of data
Audiovisual receiver with a
Blu-ray disk player
Secondary Storage
TYPES OF SECONDARY STORAGE
3. Flash Memory
• Nonvolatile memory with no moving parts
• Three forms:
1. Solid-state drive (SSD)
• Uses flash memory to store data, instructions, and information.
2. Flash memory cards
• Removable and reusable storage media that are inserted into a
flash memory slot in a digital camera, notebook, smartphone,
or other mobile device.
3. Flash memory drives (keychain drives)
• A finger-sized module of flash memory
• Plugs into a USB port
Secondary Storage
• Cloud Storage (Online Storage)
• Use of an Internet service to store data
• Top cloud storage providers:
•
•
•
•
•
•
Amazon
AT&T
Google
HP
IBM
Microsoft. 22
• Cheap or free storage options for easy sharing of documents, photos, audio files,
and videos:
•
•
•
•
•
DropBox
Microsoft’s SkyDrive
Amazon’s CloudDrive
Apple’s iCloud
Google’s Drive
FUTURE DEVELOPMENTS IN PROCESSING
& STORAGE
Future Developments in Processing
• Nanotechnology
• Use of matter on an atomic, molecular, and
supramolecular scale for industrial
purposes.
• Optical computing
• Use light to represent the on/off codes of
data
• DNA computing
• Use DNA, biochemistry, and molecular
biology hardware, instead of the traditional
electronic computing.
FUTURE DEVELOPMENTS IN PROCESSING
& STORAGE
Future Developments in Secondary Storage
• Microholographic Disk
• developed by General Electric Co.
• stores 540 gigabytes, or the content of 100 standard
DVDs, on a single DVD (equivalent to 20 single-layer Bluray disks).
• Holographic Technology
• can store data beneath the surface of a disk, whereas
CDs, DVDs, and Blu-ray disks store data only on the
surface.
•
• Five-dimensional Storage
Allows a 10-terabyte disk, the equivalent of storing
10,000 standard-definition movies on one disk.
FUTURE DEVELOPMENTS IN PROCESSING
& STORAGE
• MOLECULAR ELECTRONICS—STORAGE AT THE SUBATOMIC LEVEL
• May push secondary storage into another dimension entirely.
• Some possibilities include polymer memory, holograms, molecular
magnets, subatomic lines, and bacteria.
• Polymer memory involves developing an alternative to silicon to create
chips that store data on polymers, or plastics, which are cheaper than
silicon devices.
• NEW IMAGE-COMPRESSION TECHNOLOGY
• Compresses images far more efficiently than present methods, such as
.jpeg.
• The technology uses a sensor that uses special materials (called
metamaterials) that can bend light and radio waves in unusual ways to
compress both still and video images.