Transcript Secondary storage

TECHNOLOGY GUIDE 1
Computer Hardware
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Technology Guide Overview
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Agenda
TG1.1 Introducing Hardware Components
TG1.2 Strategic Hardware Issues
TG1.3 Innovations in Hardware Utilization
TG1.3.1 Server farms
TG1.3.2 Virtualization
TG1.3.3 Grid computing
TG1.3.4 Utility computing
TG1.3.5 Cloud computing
TG1.3.6 Edge computing
TG1.3.7 Autonomic computing
TG1.3.8 Nanotechnology
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TG1.4 The Computer Hierarchy
TG1.4.1 Supercomputers
TG1.4.2 Mainframe computers
TG1.4.3 Midrange computers
TG1.4.4 Workstations
TG1.4.5 Microcomputers
TG1.4.6 Computing devices
TG1.5 Input and Output Technologies
TG1.6 The Central Processing Unit
TG1.7 Computer Memory and Storage Systems
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LEARNING OBJECTIVES
1.
Identify the major hardware components of a computer system.
(TG1.1)
2.
Discuss strategic issues that link hardware design to business
strategy. (TG1.2)
3.
Discuss the innovations in hardware utilization. (TG1.3)
4.
Describe the hierarchy of computers according to power and their
respective roles. (TG1.4)
5.
Differentiate the various types of input and output technologies and
their uses. (TG1.5)
6.
Describe the design and functioning of the central processing unit,
and the relationship between memory and performance. (TG1.6)
7.
Discuss the relationships between microprocessor component
designs, storage systems, and performance. (TG1.7)
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TG1.1 Introducing Hardware Components
Hardware is the physical equipment used for the
input, processing, output, and storage activities of a
computer systems. It consists of the following:
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Central processing unit (CPU).
Primary storage.
Secondary storage.
Input technologies.
Output technologies.
Communication technologies.
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TG1.1 Introducing Hardware Components
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Central processing unit (CPU). Manipulates the data and
controls the tasks performed by the other components.
Primary storage. Temporarily stores data and program
instructions during processing.
Secondary storage. External to the CPU; stores data and
programs for future use.
Input technologies. Accepts data and instructions and convert
them to a form that the computer can understand.
Output technologies. Present data and information in a form
people can understand.
Communication technologies. Provide for the flow of data
from external computer networks (e.g., the Internet and intranets)
to the CPU, and from the CPU to computer networks.
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TG1.2 Strategic Hardware Issues
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For many businesspeople the most important hardware
issues are what the hardware enables, how it is
advancing, and how rapidly it is advancing.
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In many industries, exploiting computer hardware is a
key to achieving competitive advantage.
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Successful hardware exploitation comes from thoughtful
consideration of the following questions:
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How do organizations keep up with the rapid price and
performance advancements in hardware?
How should organizations determine the need for the new
hardware infrastructures, such as server farms, virtualization, grid
computing, and utility computing?
Portable computers and advanced communications technologies
have enabled employees to work from home or from anywhere.
Will these new work styles benefit employees and the
organization?
How do organizations manage such new work styles?
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TG1.3 Innovations in Hardware Utilization
TG1.3.1 Server farms
TG1.3.2 Virtualization
TG1.3.3 Grid computing
TG1.3.4 Utility computing
TG1.3.5 Cloud computing
TG1.3.6 Edge computing
TG1.3.7 Autonomic computing
TG1.3.8 Nanotechnology
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TG1.3.1 Server farms
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Server farms are massive data centres which contain
hundreds of thousands of networked computer to
facilitate the need to manage, transmit, and store the
data flowing from web-based applications for companies.
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TG1.3.2 Virtualization
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Virtualization means that servers no longer have to be
dedicated to a particular task. Server virtualization uses
software-based partitions to create multiple virtual
servers (called virtual machines) on a single physical
server.
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Many benefits accrue to organizations using
virtualization, including the following:
◦ a lower number of physical servers leads to cost savings in
equipment, energy, space in the data centre, cooling,
personnel, and maintenance
◦ enhanced organizational agility, as virtualization enables
organizations to quickly modify their systems to respond
to changing demands
◦ the focus of the information technology department can
shift from the technology itself to the services that the
technology can provide.
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TG1.3.3 Grid computing
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Grid computing applies the unused processing
resources of many geographically dispersed computers
in a network to form a virtual supercomputer.
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Target problems are usually scientific or technical in
nature and require a great number of computer
processing cycles or access to large amounts of data.
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TG1.3.4 Utility computing
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Utility computing, is where a service provider makes
unused computing resources and infrastructure
management available to customers as needed. The
service provider then charges the customer for specific
usage rather than a flat rate. Utility computing is also
called subscription computing and on-demand
computing.
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Utility computing enables companies to efficiently meet
fluctuating demands for computing power by lowering
the cost of owning hardware infrastructure.
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TG1.3.5 Cloud computing
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In cloud computing, tasks are performed by computers
physically removed from the user and accessed over a
network, in particular the Internet. The “cloud” is
composed of the computers, the software on those
computers, and the network connections among those
computers.
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The computers in the cloud are typically located in data
centres, or server farms, which can be located anywhere
in the world and accessed from anywhere in the world
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TG1.3.6 Edge computing
Edge computing is the process by which parts of
website content and processing are located close to the
user to decrease response time and lower processing
costs.
 There are three components in edge computing:
1) the computer that you use to access a website;
2) small, relatively inexpensive servers—called edge
servers—that are located at your Internet service
provider (ISP);
3) the servers of the company whose website you are
accessing.
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TG1.3.7 Autonomic computing
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Modern IT environments are becoming more complex
as the number of networked computing devices
(wireline and wireless) increases and the software on
these devices becomes more sophisticated. As a result,
IT environments are rapidly becoming difficult for
humans to adequately manage and maintain.
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To help resolve this problem, experts have designed
autonomic systems (also known as autonomic
computing) that manage themselves without direct
human intervention.
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TG1.3.8 Nanotechnology
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Nanotechnology refers to the creation of materials,
devices, and systems at a scale of 1 to 100 nanometres
(billionths of a metre).
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In the near future, still-experimental computers will be
constructed on a nanotechnology scale and could be
used literally anywhere.
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TG1.4 The Computer Hierarchy
TG1.4.1 Supercomputers
TG1.4.2 Mainframe computers
TG1.4.3 Midrange computers
TG1.4.4 Workstations
TG1.4.5 Microcomputers
TG1.4.6 Computing devices
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TG1.4.1 Supercomputers
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The term supercomputer does not refer to a specific
technology. Rather, it indicates the fastest computing
engines available at any given time.
At the time of this writing (mid-2010), the fastest
supercomputers had speeds exceeding one petaflop
(one petaflop is 1,000 trillion floating point operations
per second). A floating point operation is an arithmetic
operation involving decimals.
 Supercomputers are used primarily in scientific and
military work for computationally demanding tasks.
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TG1.4.2 Mainframe Computers
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Mainframe computers are increasingly viewed as just another type
of server, albeit at the high end of the performance and reliability
scales, they remain a distinct class of systems differentiated by
hardware and software features.
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Mainframes remain popular in large enterprises for extensive
computing applications that are accessed by thousands of users at
one time.
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Examples of mainframe applications are airline reservation systems,
corporate payroll programs, website transaction processing
systems (e.g., for Amazon and eBay), and student grade calculation
and reporting.
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TG1.4.3 Midrange computers
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Larger midrange computers, called minicomputers, are
relatively small, inexpensive, and compact computers
that perform the same functions as mainframe
computers, but to a more limited extent. In fact, the
lines between minicomputers and mainframes have
blurred in both price and performance.
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TG1.4.4 Workstations
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Computer vendors originally developed desktop
engineering workstations, or workstations for short, to
provide the high levels of performance demanded by
engineers.
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Powerful desktop size computers that run
computationally intensive scientific, engineering, and
financial applications. Workstations provide both very
high-speed calculations and high-resolution graphic
displays.
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TG1.4.5 Microcomputers
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Microcomputers—also called micros, personal
computers, or PCs (Notebooks, Laptops) —are the
smallest and least expensive category of generalpurpose computers.
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It is important to point out that people frequently
define a PC as a computer that uses the Microsoft
Windows operating system.
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The major categories of microcomputers are desktops,
thin clients, laptops and notebooks, ultramobile PCs, and
netbooks.
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TG1.4.6 Computing devices
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Improved computer technology has led to the
development of improved, ever-smaller computing and
communication devices. Technologies such as wearable
computing and communication devices are now
common. This section briefly looks at some of these
new devices:
◦ Wearable computers
◦ Embedded computers
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Wearable computers (wearable devices) are designed to
be worn and used on the body. Industrial applications of
wearable computers include systems for factory
automation, warehouse management, and performance
support, such as viewing technical manuals and diagrams
while building or repairing something.
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Embedded computers are placed inside other products
to add features and capabilities.
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TG1.5 Input and Output Technologies
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Input technologies allow people and other technologies to put data
into a computer. The two main types of input devices are human
data-entry devices and source-data automation devices. Table TG1.1
describes the various input devices.
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The output generated by a computer can be transmitted to the
user via several output devices and media. These devices include
monitors, printers, plotters, and voice. Table TG1.2 describes the
various output devices.
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TG1.6 The Central Processing Unit
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The central processing unit (CPU) performs the actual
computation or “number crunching” inside any
computer.
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The CPU is a microprocessor (for example, a Nehalem
chip by Intel) made up of millions of microscopic
transistors embedded in a circuit on a silicon wafer or
chip. Hence, microprocessors are commonly referred to
as chips.
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How the CPU works:
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Advances in Microprocessor Design
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Moore’s Law. In 1965, Gordon Moore, a co-founder of Intel
Corporation, predicted that microprocessor complexity would
double approximately every two years.
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TG1.7 Computer Memory and Storage
Systems
Memory Capacity
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CPUs process only binary units—0s and 1s—which are translated
through computer languages (covered in Technology Guide 2) into
bits. A particular combination of bits represents a certain
alphanumeric character or a simple mathematical operation.
Normally, eight bits are needed to represent any one of these
characters. This 8-bit string is known as a byte.
The storage capacity of a computer is measured in bytes.
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Kilobyte. Kilo means 1 thousand, so a kilobyte (KB) is approximately
1,000 bytes. Actually, a kilobyte is 1,024 bytes.
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Megabyte. Mega means 1 million, so a megabyte (MB) is approximately 1
million bytes. Most personal computers have hundreds of megabytes of
RAM memory (a type of primary storage, discussed later).
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Gigabyte. Giga means 1 billion, so a gigabyte (GB) is approximately 1
billion bytes. The storage capacity of a hard drive (a type of secondary
storage, discussed shortly) in modern personal computers is hundreds of
gigabytes.
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Terabyte. A terabyte is approximately 1 trillion bytes.
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Petabyte. A petabyte is approximately 1,000 terabytes.
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Exabyte. An exabyte is approximately 1,000 petabytes.
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Zettabyte. A zettabyte is approximately 1,000 exabytes
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Type of primary memory
◦ Random Access Memory
◦ Cache Memory
◦ Read-only Memory
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Storage systems
 Primary storage
 Secondary storage
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Primary storage. It is called “primary” because it stores
small amounts of data and information that will be used
immediately by the CPU.
Primary storage stores three types of information for very
brief periods of time:
1) data to be processed by the CPU
2) instructions for the CPU as to how to process the data,
3) operating system programs that manage various aspects
of the computer’s operation.
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Secondary storage, which stores much larger amounts
of data and information (an entire software program, for
example) for extended periods of time.
Secondary storage has the following characteristics:
 It is nonvolatile.
 It takes more time to retrieve data from secondary storage
 It is cheaper than primary storage
 It can take place on a variety of media
 The overall trends in secondary storage are toward more directaccess methods, higher capacity with lower costs, and increased
portability.
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Type of secondary storage
 Magnetic Media
◦ Magnetic tape
◦ Magnetic disks
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Optical Storage Devices
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Magnetic tape is kept on a large open reel or in a smaller
cartridge or cassette. Although this is an old technology, it remains
popular because it is the cheapest storage medium, and it can
handle enormous amounts of data.
Magnetic disks are a form of secondary storage on a magnetized
disk that is divided into tracks and sectors that provide addresses
for various pieces of data.
Optical storage devices do not store data via magnetism. Rather,
a laser reads the surface of a reflective plastic platter. Optical disk
drives are slower than magnetic hard drives, but they are less
susceptible to damage from contamination and they are less fragile.
Types of optical disks include compact disk read-only memory
(CD-ROM) and digital video disk (DVD).
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Enterprise Storage Systems
An enterprise storage system is an independent, external
system with intelligence that includes two or more
storage devices.
Enterprise storage systems provide large amounts of
storage, high-performance data transfer, a high degree of
availability, protection against data loss, and
sophisticated management tools.
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There are three major types of enterprise storage
systems:
 Redundant arrays of independent disks
 Storage area networks
 Network-attached storage
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Redundant arrays of independent disks
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To improve reliability and to protect the data in their enterprise
storage systems, many organizations use redundant arrays of
independent disks (RAID) storage products.
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RAID is an enterprise storage system that links groups of standard
hard drives to a specialized microcontroller. The microcontroller
coordinates the drives so they appear as a single logical drive, but
they take advantage of the multiple physical drives by storing data
redundantly, meaning data that are duplicated in multiple places.
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This arrangement protects against data loss due to the failure of
any single drive.
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Storage area networks
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Storage Area Network (SAN) is an enterprise storage system
architecture for building special, dedicated networks that allow
rapid and reliable access to storage devices by multiple servers.
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Storage over IP, sometimes called IP over SCSI or iSCSI, is a
technology that uses the Internet protocol to transport stored
data among devices within an SAN.
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SANs employ storage visualization software to graphically plot an
entire network and allow storage administrators to monitor all
networked storage devices from a single console.
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Network-attached storage
 Network-attached Storage (NAS) device is an
enterprise storage system in which a special-purpose
server that provides file storage to users who access
the device over a network.
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The NAS server is simple to install (i.e., plug-and play)
and works exactly like a general-purpose file server, so
no user retraining or special software is needed.
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