Aula 3 14032013 sii-v1

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Class 3 SII

Class 3 SII

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  • 1. Sistemas de Informaçãopara a Indústria Class 3 Architectures of IS Ano 2013 António Grilo Prof. Auxiliar FCT-UNL Sistemas de Informação para Indústria 1Departamento de Engenharia Mecânica e Industrial © António Grilo 2013
  • 2. BIT AND BYTEBit - 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 andtelecommunications; it is the amount of information stored by a digital device orother physical system that exists in one of two possible distinct states. Bits can beimplemented in many forms. In most modern computing devices, a bit is usuallyrepresented by an electrical voltage or current pulse, or by the electrical state of aflip-flop circuit.Byte - String of bits, usually eight, stores one number or character. The byte is aunit of digital information in computing and telecommunications that mostcommonly consists of eight bits. Historically, a byte was the number of bits used toencode a single character of text in a computer and for this reason it is the basicaddressable element in many computer architectures. The size of the byte hashistorically been hardware dependent and no definitive standards existed thatmandated the size. The de facto standard of eight bits is a convenient power oftwo permitting the values 0 through 255 for one byte. The popularity of majorcommercial computing architectures have aided in the ubiquitous acceptance ofthe 8-bit size Sistemas de Informação para Indústria 2 Departamento de Engenharia Mecânica e Industrial © António Grilo 2013
  • 3. BIT AND BYTE Sistemas de Informação para Indústria 3 Departamento de Engenharia Mecânica e Industrial © António Grilo 2013
  • 4. INFORMATION TECHNOLOGY (IT) INFRASTRUCTUREIntegrated framework upon which digital networks operate. Thisinfrastructure 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 introducedPersonal computer era: 1981 to present:- 1981 Introduction of IBM PC- Proliferation in 80s, 90s resulted in growth of personal software Sistemas de Informação para Indústria 4 Departamento de Engenharia Mecânica e Industrial © António Grilo 2013
  • 5. INFORMATION TECHNOLOGY (IT) INFRASTRUCTUREClient/server era: 1983 to present:- Desktop clients networked to servers, with processing work splitbetween 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 Internetstandards and enterprise applicationCloud Computing: 2008 to present- Refers to a model of computing where firms and individuals obtaincomputing power and software applications over the Internet or othernetwork- Fastest growing form of computing Sistemas de Informação para Indústria 5 Departamento de Engenharia Mecânica e Industrial © António Grilo 2013
  • 6. TECHNOLOGY DRIVERS OF INFRASTRUCTURE EVOLUTION Moore’s 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.. Metcalfe’s 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. Sistemas de Informação para Indústria 6 Departamento de Engenharia Mecânica e Industrial © António Grilo 2013
  • 7. 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 Sistemas de Informação para Indústria 7 Departamento de Engenharia Mecânica e Industrial © António Grilo 2013
  • 8. COMPONENTS OF A COMPUTER NETWORKTwo 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 Sistemas de Informação para Indústria 8 Departamento de Engenharia Mecânica e Industrial © António Grilo 2013
  • 9. DIGITAL NETWORKS Sistemas de Informação para Indústria 9Departamento de Engenharia Mecânica e Industrial © António Grilo 2013
  • 10. CLIENT/SERVER COMPUTINGThe client–server model is a computing model that acts as distributedapplication which partitions tasks or workloads between the providers of aresource or service, called servers, and service requesters, called clients.Often clients and servers communicate over a computer network onseparate hardware, but both client and server may reside in the samesystem. A server machine is a host that is running one or more serverprograms which share their resources with clients. A client does not shareany of its resources, but requests a servers content or service function. Sistemas de Informação para Indústria 10 Departamento de Engenharia Mecânica e Industrial © António Grilo 2013
  • 11. PACKET SWITCHINGMethod of slicing digital messages into parcels (packets), sending packetsalong different communication paths as they become available, and thenreassembling packets at destination. Previous circuit-switched networksrequired assembly of complete point-to-point circuit. Packet switching ismore efficient use of network’s communications capacity. Sistemas de Informação para Indústria 11 Departamento de Engenharia Mecânica e Industrial © António Grilo 2013
  • 12. 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 Sistemas de Informação para Indústria 12 Departamento de Engenharia Mecânica e Industrial © António Grilo 2013
  • 13. TYPES OF NETWORKSLocal-area networks (LANs)- Client/server or peer-to-peer- Ethernet – physical network standard- Topologies: star, bus, ringCampus-area networks (CANs)Wide-area networks (WANs)Metropolitan-area networks (MANs) Sistemas de Informação para Indústria 13 Departamento de Engenharia Mecânica e Industrial © António Grilo 2013
  • 14. NETWORKSPhysical transmission media:- Twisted wire (modems)- Coaxial cable- Fiber optics and optical networksWireless transmission media and devices:- Microwave- Satellites- Cellular telephones Sistemas de Informação para Indústria 14 Departamento de Engenharia Mecânica e Industrial © António Grilo 2013
  • 15. PROPRIETARY SOFTWARE VS OPEN SOURCEProprietary software is software developed by a supplier and madeavailable for you to use under an end-user licence agreement (EULA),which you effectively accept when you install the software. The licencesets out how the software can be used and usually prohibits you fromdoing certain things, like making copies of the software and passing themon; or selling your licence to someone else.Most proprietary software comes without the source code. This is the codeoriginally written by the programmer. Without this code neither you nor anyother software supplier can make changes to the software package.When you buy a proprietary software package you are not buying thesoftware - 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. Sistemas de Informação para Indústria 15 Departamento de Engenharia Mecânica e Industrial © António Grilo 2013
  • 16. PROPRIETARY SOFTWARE VS OPEN SOURCEOpen source software is made available under a licence that allows you tomake copies and pass them on to anyone. The software comes with itssource code - which you can change to meet your needs.Licences for open source software do vary. Some licences require to makeany changes made to the source code publicly available, while others willallow to keep those changes private. The licence agreement shhould beread before using or changing the software.Open source software is usually available for free download or off-the-shelf at a low cost. Sistemas de Informação para Indústria 16 Departamento de Engenharia Mecânica e Industrial © António Grilo 2013