Asper School of Business University of Manitoba Systems

Asper School of Business University of Manitoba Systems Analysis & Design Instructor: Bob Travica System architectures Updated: 2018

Outline n n n n n Single computer architecture, Centralized arch. Client-Server architecture, Distributed arch. N-Tier Client-Server architecture Middleware Computer networks The Internet, Intranets, and Extranets Internet-based architectures Services Oriented Architecture Cloud computing and system architectures 3510 Systems Analysis & Design * Bob Travica 2

System Architecture concept n System Architecture = overall design, blue print, “look”, “big picture” n Focus on the structure of an IS as a whole n Hardware pieces/brands, software (sometimes), databases, networks, security n Sub-systems, modules, layers, spatial arrangement, system views n Not a formally defined concept; no formal diagrams 3510 Systems Analysis & Design * Bob Travica 3

System Architecture visual See the note in the footer 3510 Systems Analysis & Design * Bob Travica 4

Single-computer architecture n Single system attached to peripheral devices (e. g. , mainframe-based) n Advantages: easier to design, build, operate, maintain n Disadvantages: limits in scaling up and software/hardware standards (e. g. , tight coupling of operating system and application software) 3510 Systems Analysis & Design * Bob Travica 5

Client-Server architecture Some processing; User interface (Fat client) User interface (Thin client) n n Data storage; Some processing Client: requestor of resources or services from a server. Services: data storage & data processing (functionality). Recall the service view of IS. The third service - user interface – is managed by the client. Server: responder to Client’s requests* Architectures differ with regard who manages storage and processing service. 3510 Systems Analysis & Design * Bob Travica 6

Client-Server architecture (cont. ) n Client and server communicate via well-defined protocols over a physical channel n Client/server architecture advantages: n Location flexibility (equipment can be moved easily) n Larger scalability (IS open to growth) n Maintenance flexibility (application software upgrades easier) n Client/server architecture disadvantages n Complexity (multiple pieces of equipment & connections) n Reliability (network transfers as part of an IS) n Security issues (network security risks) 3510 Systems Analysis & Design * Bob Travica 7

N-Tier architecture n Partitioning system into less tightly coupled parts n 3 -tiers (layers) frequent, placing each of 3 services on different hardware: Function request n The storage layer – data, database (backend) n The business logic layer - functionality n The view/presentation layer - user interface (front end) 3510 Systems Analysis & Design * Bob Travica 8

Middleware n Part of a system connecting front-end and back-end n Part of a system where business processes and the data model are defined; typical for enterprise systems n Can be object-based while other parts are not (legacy systems, relational databases) n Can contain drivers for back-end DBs (system interface) n A system part connecting modules of application software n Can have multiple layers (data model, DB drivers) 3510 Systems Analysis & Design * Bob Travica 9

Computer networks n Support distributed system architecture (client-server) n LAN vs. WAN n Computer data transfer capabilities: n Enable data transfer (e. g. , remote database access, remote login) n Provide infrastructure for human communication systems 3510 Systems Analysis & Design * Bob Travica 10

Network architecture issues n Issues: n Communication protocols selection (net software, Ethernet, TCP/IP, X. 25…) n Network configuration (bus, star, wheel, mesh) Mesh Ensuring sufficient network capacity n Security Domain of Network Administrator (a highly demanded systems specialty) n n n ! Check control questions in the footnote ! 3510 Systems Analysis & Design * Bob Travica 11

The Internet, Intranets, & Extranets n Internet: LANs, WANs, and individual devices connected via TCP/IP software n The Web: Collection of resources accessed over the Internet; specific addressing scheme n Intranet: private net accessible to internal users n Extranet: intranet extended to include some external users n Virtual private network (VPN): uses public network as if it is private 3510 Systems Analysis & Design * Bob Travica 12

Internet-based architectures n Web uses client/server architecture n Characteristics: n n Web resources (data, processing) are managed by servers n Clients get services from servers n Web protocols define valid resource formats and communication standards n Object-based software SOA (next slides) 3510 Systems Analysis & Design * Bob Travica 13

Services Oriented Architecture (SOA) n Recall the SOA view of information systems. n SOA is a set of methods for designing and developing application software in the form of interoperable services. n Services are functions that are built as software components pieces of code or data structures. n Services can be used for different purposes, in various software segments (Examples: Web services as foreign language spell checker for a word processor system; mashup in Google maps). n SOA draws on component software, object oriented approach, modular programming, distributed computing, cross-platform computing, & cloud computing (Saa. S). n SOA aims to allow users to assemble entire large programs even just for a purpose at hand. 3510 Systems Analysis & Design * Bob Travica 14

SOA (more) n SOA components are put together by a process of orchestration using a list of SOA components needed. n Components are called upon their interface (an instance of system interface) which advertises a component's functionality and protocols. n Protocol describes messages to a component (e. g. , what data can be inputted to trigger the function the component represents) – metadata. * n SOA principles emphasize a pragmatic approach (footnote**) 3510 Systems Analysis & Design * Bob Travica 15

SOA Benefits & Costs n n SOA Benefits: n cost savings in system development n more flexible software to meet changing business needs (ad hos apps) n more complex software possible without complexity & cost demanded by the final functionality reached (e. g. , mashups) SOA Costs: n integration of components (the interface issues) n components' quality (testing, assurances) n development continuity 3510 Systems Analysis & Design * Bob Travica 16

Internet-based architectures n Advantages of Web/Internet: n n (cont. ) Flexibility, accessibility, low cost communication, widely used standards Disadvantages of Web/Internet: n Security, reliability, throughput, quality, volatile standards… But improvements are being made. 3510 Systems Analysis & Design * Bob Travica 17

Cloud computing n Cloud computing (Cloud) is a technical and business model that complements or substitutes organizational information systems. Business model is renting. n Some aspects of Cloud resemble client-server architecture, but there is much more to it. CLOUD CLIENT (USER) host whole systems (Saa. S) host databases, development resources (Paa. S) host hardware, storage, virtual machines (Iaa. S) 3510 Systems Analysis & Design * Bob Travica CLOUD VENDOR 18

Cloud services n Cloud computing services Cloud Client Web browser, desktops computers, mobile devices Internet Private network Software as a Service accounting, customer relationship management, human resource management… Platform as a Service software development resources, databases, servers Infrastructure as a Service computers, virtual machines, data storage, virtual local area networks, firewalls See footnote 3510 Systems Analysis & Design * Bob Travica 19

Cloud effects n Cloud builds on component software, OO methods, computer networks… n Cloud may enable new forms of organizing, as virtual organization (VO). * ! Check control questions in the footnote ! 3510 Systems Analysis & Design * Bob Travica 20/20

That’s all, folks! There might be more carrots in the footer though… 3510 Systems Analysis & Design * Bob Travica 21