Transcript of Class 3 Architectures of IS
- 1. Sistemas de Informao para Indstria Antnio Grilo
2015Departamento de Engenharia Mecnica e Industrial 1 Class 3
Architectures of IS Ano 2015 Sistemas de Informao para a Indstria
Antnio Grilo Prof. Auxiliar FCT-UNL
- 2. Sistemas de Informao para Indstria Antnio Grilo
2015Departamento de Engenharia Mecnica e Industrial 2 BIT AND BYTE
Bit - Binary digit, represents smallest unit of data in the form of
either 0 or 1. A bit (a contraction of binary digit) is the basic
unit of information in computing and telecommunications; it is the
amount of information stored by a digital device or other physical
system that exists in one of two possible distinct states. Bits can
be implemented in many forms. In most modern computing devices, a
bit is usually represented by an electrical voltage or current
pulse, or by the electrical state of a flip-flop circuit. Byte -
String of bits, usually eight, stores one number or character. The
byte is a unit of digital information in computing and
telecommunications that most commonly consists of eight bits.
Historically, a byte was the number of bits used to encode a single
character of text in a computer and for this reason it is the basic
addressable element in many computer architectures. The size of the
byte has historically been hardware dependent and no definitive
standards existed that mandated the size. The de facto standard of
eight bits is a convenient power of two permitting the values 0
through 255 for one byte. The popularity of major commercial
computing architectures have aided in the ubiquitous acceptance of
the 8-bit size
- 3. Sistemas de Informao para Indstria Antnio Grilo
2015Departamento de Engenharia Mecnica e Industrial 3 BIT AND
BYTE
- 4. Sistemas de Informao para Indstria Antnio Grilo
2015Departamento de Engenharia Mecnica e Industrial 4 INFORMATION
TECHNOLOGY (IT) INFRASTRUCTURE Integrated framework upon which
digital networks operate. This infrastructure includes data
centers, computers, computer networks, Database Management devices,
and a regulatory system. Evolution of IT infrastructure:
General-purpose mainframe & minicomputer era: 1959 to present -
1958 IBM first mainframes introduced - 1965 Less expensive DEC
minicomputers introduced Personal computer era: 1981 to present: -
1981 Introduction of IBM PC - Proliferation in 80s, 90s resulted in
growth of personal software
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2015Departamento de Engenharia Mecnica e Industrial 5 INFORMATION
TECHNOLOGY (IT) INFRASTRUCTURE Client/server era: 1983 to present:
- Desktop clients networked to servers, with processing work split
between clients and servers - Network may be two-tiered or
multitiered (N-tiered) - Various types of servers (network,
application, Web) Enterprise computing era: 1992 to present: - Move
toward integrating disparate networks, applications using Internet
standards and enterprise application Cloud Computing: 2008 to
present - Refers to a model of computing where firms and
individuals obtain computing power and software applications over
the Internet or other network - Fastest growing form of
computing
- 6. Sistemas de Informao para Indstria Antnio Grilo
2015Departamento de Engenharia Mecnica e Industrial 6 TECHNOLOGY
DRIVERS OF INFRASTRUCTURE EVOLUTION Moores law and microprocessing
power - Computing power doubles every 18 months. Since the first
magnetic storage device was used in 1955, the cost of storing a
kilobyte of data has fallen exponentially, doubling the amount of
digital storage for each dollar expended every 15 months, on
average.. Metcalfes Law and network economics - Value or power of a
network grows exponentially as a function of the number of network
members. As network members increase, more people want to use it
(demand for network access increases). Declining communication
costs (towards 0) and the Internet, with an estimated 1.5 billion
people worldwide have Internet access. Standards and network
effects - Specifications that establish the compatibility of
products and the ability to communicate in a network unleash
powerful economies of scale and result in price declines as
manufacturers focus on the products built to a single
standard.
- 7. Sistemas de Informao para Indstria Antnio Grilo
2015Departamento de Engenharia Mecnica e Industrial 7 ADVANCES IN
COMPUTER POWER: MACHINE BEATS MAN WATSON, IBM, 2008 JEOPARDY,
2008
- 8. Sistemas de Informao para Indstria Antnio Grilo
2015Departamento de Engenharia Mecnica e Industrial 8 ARTIFICIAL
INTELLIGENCE
- 9. Sistemas de Informao para Indstria Antnio Grilo
2015Departamento de Engenharia Mecnica e Industrial 9 IT
INFRASTRUCTURE HAS 7 MAIN COMPONENTS Computer hardware platforms
Operating system platforms Enterprise business applications Data
management and storage Networking/telecommunications platforms
Internet platforms Consulting system integration services
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2015Departamento de Engenharia Mecnica e Industrial 10 COMPONENTS
OF A COMPUTER NETWORK Two or more connected computers. Major
components in simple network: Client computer Server computer
Network interfaces (NICs) Connection medium Network operating
system Hub or switch Router
- 11. Sistemas de Informao para Indstria Antnio Grilo
2015Departamento de Engenharia Mecnica e Industrial 11 DIGITAL
NETWORKS
- 12. Sistemas de Informao para Indstria Antnio Grilo
2015Departamento de Engenharia Mecnica e Industrial 12
CLIENT/SERVER COMPUTING The clientserver model is a computing model
that acts as distributed application which partitions tasks or
workloads between the providers of a resource or service, called
servers, and service requesters, called clients. Often clients and
servers communicate over a computer network on separate hardware,
but both client and server may reside in the same system. A server
machine is a host that is running one or more server programs which
share their resources with clients. A client does not share any of
its resources, but requests a server's content or service
function.
- 13. Sistemas de Informao para Indstria Antnio Grilo
2015Departamento de Engenharia Mecnica e Industrial 13 PACKET
SWITCHING Method of slicing digital messages into parcels
(packets), sending packets along different communication paths as
they become available, and then reassembling packets at
destination. Previous circuit-switched networks required assembly
of complete point-to-point circuit. Packet switching is more
efficient use of networks communications capacity.
- 14. Sistemas de Informao para Indstria Antnio Grilo
2015Departamento de Engenharia Mecnica e Industrial 14 TRANSMISSION
CONTROL PROTOCOL / INTERNET PROTOCOL (TCP/IP) Connectivity between
computers enabled by protocols. Protocols are rules that govern
transmission of information between two points. It has four layers:
- Application layer - Transport layer - Internet layer - Network
interface layer
- 15. Sistemas de Informao para Indstria Antnio Grilo
2015Departamento de Engenharia Mecnica e Industrial 15 TYPES OF
NETWORKS Local-area networks (LANs) - Client/server or peer-to-peer
- Ethernet physical network standard - Topologies: star, bus, ring
Campus-area networks (CANs) Wide-area networks (WANs)
Metropolitan-area networks (MANs)
- 16. Sistemas de Informao para Indstria Antnio Grilo
2015Departamento de Engenharia Mecnica e Industrial 16 NETWORKS
Physical transmission media: - Twisted wire (modems) - Coaxial
cable - Fiber optics and optical networks Wireless transmission
media and devices: - Microwave - Satellites - Cellular
telephones
- 17. Sistemas de Informao para Indstria Antnio Grilo
2015Departamento de Engenharia Mecnica e Industrial 17 PROPRIETARY
SOFTWARE VS OPEN SOURCE Proprietary software is software developed
by a supplier and made available for you to use under an end-user
licence agreement (EULA), which you effectively accept when you
install the software. The licence sets out how the software can be
used and usually prohibits you from doing certain things, like
making copies of the software and passing them on; or selling your
licence to someone else. Most proprietary software comes without
the source code. This is the code originally written by the
programmer. Without this code neither you nor any other software
supplier can make changes to the software package. When you buy a
proprietary software package you are not buying the software - you
are buying the right to use the software in a specific way. The
software company owns the software. Most off-the-shelf packages are
proprietary software.
- 18. Sistemas de Informao para Indstria Antnio Grilo
2015Departamento de Engenharia Mecnica e Industrial 18 PROPRIETARY
SOFTWARE VS OPEN SOURCE Open source software is made available
under a licence that allows you to make copies and pass them on to
anyone. The software comes with its source code - which you can
change to meet your needs. Licences for open source software do
vary. Some licences require to make any changes made to the source
code publicly available, while others will allow to keep those
changes private. The licence agreement shhould be read before using
or changing the software. Open source software is usually available
for free download or off-the- shelf at a low cost.