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COMP1321 Digital Infrastructure

COMP1321 Digital Infrastructure. Richard Henson March 2018. Week 19 – Servers, Thin Clients, Connectivity, Mixed Networks, and Virtualisation. Objectives Explain levels of distribution in client-server networking, and relate the use of different levels to organisational requirements

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COMP1321 Digital Infrastructure

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  1. COMP1321Digital Infrastructure Richard Henson March2018

  2. Week 19 – Servers, Thin Clients, Connectivity, Mixed Networks, and Virtualisation • Objectives • Explain levels of distribution in client-server networking, and relate the use of different levels to organisational requirements • Explain the process of terminal emulation and how terminal services and other software can deliver this to the desktop • Explain virtualisation and install a virtual machine

  3. A matter of Fashion or Functionality? • Very early days of networking… • no clients… (or even users!) • specialist staff only • all computer input via cards and tape • output only to printers • Original clients (e.g. “Wang VDU) early 1970s really were “dumb”! • microprocessor only just been invented! • interrupt driven processing hadn’t been implemented

  4. Servers provide Services Central host/server • In the early days of organisational computing, the server (host) was king • user device VDU (Visual Display Unit) or Terminal had no processing ability • everything controlled from the centre, with “dumb” terminal on employee’s desk VDUs (screen and keyboard)

  5. The dawn of the “intelligent client” • First “8 bit” processor (Intel 8008) available in 1973… • two years to develop a motherboard & operating system • expected that “users” would write their own apps • 1975, the first microcomputer: The Altair • scope for “intelligence on the desktop” • Many other Micros followed: • Commodore • Atari • Sinclair ZX81

  6. Success of the Business Micro • By 1981, microcomputers popular in the home… • IBM PC (16 bit) was introduced to see whether business would make use of desktop computing… • Business loved the IBM micro • applications became commercially available • large organisations wanted to exchange data… • between desktops • between desktop and server

  7. Desktop Machines Networked • Through OSI & IEEE802 standards, the networked PCs & LANs became possible… • Novell Netware made a PC a server • Communicated with PC clients… very popular • PCs linked to “host” computers previously using only dumb terminals… • DEC PCSA a popular step forward using TCP/IP • meant mainframes running TCP/IP could interface with microcomputers!!!

  8. Ubiquitous Client platforms • Environment for running software even more miniaturised… e.g. • Intel motherboard etc./Windows 10 • Diff Intel motherboard/AppleOS • Smartphone/Android • Sometimes useful to be able to run more than one platform on a single machine…

  9. Clients make services accessible to users… • Servers hold secure data… • should be kept well away from users! • Users can only access data/resources on a client-server network via a request to a server • Depending on the server architecture: • make requests directly via commands inputted from a dumb terminal • make requests from an intelligent client through interprocess communication

  10. Front End and Back End • As client-server computing entered most organisations… • Client desktop – previously VDU - known as “front-end” (or “front office”) • Anything to do with servers/shared applications and information stores – previously the mainframe - known as “back end” (or “back office”)

  11. Clients, Platforms, and Flexibility • Demand for multiple client platforms for the user… • but multiple devices/machines expensive • virtual machine got round this

  12. Virtual Machines • Mounting a platform that is solely software based • running on top of an existing hardware/software platform • e.g. • Intel/Windows 7/8/10 client • Apple client

  13. Virtualisation Platforms • Software environment running on top of an existing platform • allows more than one virtual machine to run on top of a traditional hardware/software platform • Client operating system installed on top of virtualisation platform

  14. Examples: • VMWare • Virtual Box • Citrix • Hyper-V Virtual machine e.g. running Windows 10 Virtual machine e.g. running Server 2016 virtualisation platform Hardware/software platform e.g. Intel/Windows

  15. Virtualisation (Windows 2016 Server, on VMware, etc.) • The use of software to allow a piece of hardware to run multiple operating system images at the same time • possible to run Windows OS under Mac OS • run multiple versions of Windows OS on the same PC • Enables the creation of a “virtual” (rather than actual) version of any software environment on the desktop, e.g. operating Systems, a server, a storage device, an application

  16. “The Cloud” • Outsourcing on a grand scale… • With connectivity via world wide web • “Back to the Future” • Quote from IBM in 1950s: • “I think there is a world market for about five computers.” attributed to J. Watson • “The cloud” will behave like just one massive mainframe computer providing all user services • No powerful clients needed… just enough processing at the client end to run a browser • could be a very small device (Smartphone) • could use wireless protocols to connect…

  17. Web Services and The Cloud • Companies like Amazon, Google (apps), and salesforce.com have created web services (http/s) and made them available to a wider public for storing their data • this approach benefits companies most that are experience relatively quick growth • instead of getting new storage resources every year, organisations can quickly and easily purchase more "cloud space"

  18. Cloud Computing Model

  19. Cloud Services, the Future, and Security • Cloud computing can offer applications as-a-service as well… • a future is predicted where everything is outsourced and no kind of local CPU is even needed • employees will simply have a monitor, keyboard, and mouse that will allow them to connect to the cloud for all of their resources (!) • but will this be secure? And what comeback will organisations have if something goes wrong?

  20. What (physically) is The Cloud? • Lots of servers connected together in clusters to provide different services via the www • uses essentially the same TCP/IP protocols • different ports for different applications • attractive and powerful, but… • disadvantages of outsourcing in terms of control • and with the extra challenge that the user doesn’t know where their data physically is at a particular time… SCARY?

  21. Data Protection, Organisations, and the Cloud • Lot of pressure on organisations to put digital infrastructure “in the cloud” • Less hassle? • someone else managing your data • cheaper… don’t need servers or expensive staff to manage them • don’t even need “back office” premises!

  22. Data Protection and the Cloud • Disadvantages… • concern about loss of control of organisational data • dependent on bandwidth of cloud provider • what if cloud provider gets hacked? • where is the data being held? “third country”? • legal concern whilst UK in the EEA… • UK soon to leave EU? And the EEA? • will then be a “third” country anyway…

  23. Setting up a Virtualisation Platform • Many products available: • Citrix metaframe • VirtualBox • VMWare • Microsoft Hyper V • All available on Windows client converting it to a virtualisation platform

  24. Hyper-V • New for Windows 2008 Server • Subsequently available to Windows clients • PC/Laptop running Windows 10 good platform for virtualisation platforms • e.g. Hyper-V • can run several virtual machines • can even use virtual “switches” to communicate with one another…

  25. Thanks for listening

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