1. COMP2322 Network Management Richard Henson Worcester Business School March 2016

2. Week 5 – Thin Clients, Connectivity, Mixed Networks, and Virtualisation Objectives Objectives  Explain levels of distribution in client-server networking, and relate choice to organisational requirements  Explain dumb terminals/terminal emulation and how terminal services and other software can deliver this ecomically to the desktop  Explain virtualisation and install a virtual machine

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

4. The dawn of the “intelligent client” First “8 bit” processor (Intel 8008) available in 1973… First “8 bit” processor (Intel 8008) available in 1973…  Two more years to develop a motherboard & operating system 1975, the first microcomputer: The Altair1975, the first microcomputer: The Altair scope for “intelligence on the desktop”scope for “intelligence on the desktop” expected that “users” would write their own appsexpected that “users” would write their own apps By 1981, microcomputers popular in the home… By 1981, microcomputers popular in the home…  IBM PC introduced to see whether business would make use of desktop computing…

5. Success of the Business Micro Businesses used the IBM micro Businesses used the IBM micro  applications became commercially available  large organisations wanted to exchange data… between desktopsbetween desktops between desktop and serverbetween desktop and server Through OSI & IEEE802 standards, the networked PC & LANs became possible: Through OSI & IEEE802 standards, the networked PC & LANs became possible:  centralised computers could interface with microcomputers  popular early implementations: n Novell Netware n DEC PCSA

6. Servers provide Services In the early days, the server (host) was king In the early days, the server (host) was king  user device VDU (Visual Display Unit) or Terminal had no processing ability  everything controlled from the centre Once microcomputers could connect to servers Once microcomputers could connect to servers  host-VDU/terminal -> server-client  clients provided richer user experience But, servers retained control But, servers retained control  provided client access to resources via services

7. Client platforms Environment for running software… e.g. Environment for running software… e.g.  Intel motherboard etc./Windows 7  Intel motherboard etc./AppleOS  Smartphone/Android Sometimes useful to be able to run more than one platform on a single machine. Sometimes useful to be able to run more than one platform on a single machine.

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

9. Virtual Machines Replacement of an existing hardware/software platform by a platform that is solely software based Replacement of an existing hardware/software platform by a platform that is solely software based Virtual Machine still has to run on an existing platform e.g. Virtual Machine still has to run on an existing platform e.g.  Intel/Windows 7/8/10 client  Apple client

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

11. Examples: VMWare VMWare Virtual Box Virtual Box Citrix Citrix Hyper-V Hyper-V Hardware/software platform e.g. Intel/Windows virtualisation platform Virtual machine e.g. running Windows 10 Virtual machine e.g. running Server 2008

12. Virtualisation (Windows 2008 Server, Citrix, VMware, etc.) The use of software to allow a piece of hardware to run multiple operating system images at the same time 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 or networks, an application 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 or networks, an application

13. “The Cloud” Outsourcing on a grand scale… Outsourcing on a grand scale…  With connectivity via world wide web “Back to the Future” “Back to the Future”  Quote from IBM in 1950s: “I think there is a world market for about five computers.” attributed to J. Watson“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 FAT clients needed… just enough processing at the client end to run a browser could be a very small devicecould be a very small device could use wireless protocols to connect…could use wireless protocols to connect…

14. Web Services and The Cloud Companies like Amazon, Google (apps), and salesforce.com have created web services (XML/http) and made them available to a wider public for storing their data Companies like Amazon, Google (apps), and salesforce.com have created web services (XML/http) 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"

15. Cloud Services, the future, and Security Cloud computing can offer applications as-a- service as well… 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?

16. What (physically) is The Cloud? Lots of servers connected together in clusters to provide different services via the www Lots of servers connected together in clusters to provide different services via the www  Attractive and powerful, but…  disadvantages of outsourcing in terms of control and with the extra challenge that the user doesn’t know where there data physically is at a particular time… SCARY?and with the extra challenge that the user doesn’t know where there data physically is at a particular time… SCARY? Server location also a matter of some concern for legal reasons… Server location also a matter of some concern for legal reasons…

17. Thanks for listening Thanks for listening