IT Infrastructure

Architecture
Infrastructure Building Blocks
and Concepts

End user devices

(chapter 13)
Agenda

● Introduction
● History
● Building Blocks
● End User Devices:
 Availability
 Performance
 Security
2
Introduction

• Humans interact with

applications using end user
devices
• Typical end user devices
are:
 Desktop PCs
 Laptops
 Virtual desktops
 Mobile devices like phones
and tablets
 Printers
 History
● The first end user devices were teletypes
● Teletypes were electromechanical typewriters
 Provided a user interface to early mainframes
 Sending typed data to the computer and printing the response
● Electronic terminals replaced the teletypes
● Terminals provided a monitor screen instead of printed paper but were “dumb”
● In 1981, IBM introduced the Personal Computer (PC)
● The IBM PC became the de facto end user device in many office environments
 Office workers had full control over their own computer for the first time

4
History - Personal Computers
● IBM sold an IBM PC Technical Reference Manual
● Many parties copied the PC - PC clones or IBM-compatible PCs
● One of the first and most successful companies building clones was Compaq, which
would later become part of HP
● All of the IBM PC software was developed by third parties
 Microsoft provided the DOS operating system and office tools like Word and Excel

● In 1984, Apple introduced the Apple Macintosh

 The first commercially successful personal computer to feature a mouse and a GUI rather than a
command line interface
 Designed to be used by consumers, and not as an office tool

● Both the Mac and the PC evolved over time to become much faster, Introduction to
smartphones and tablet made it more interactive for end user
5
End-User Devices Building Blocks

6
Desktop, PC and Laptops
● Over the years, PCs have become very powerful
 Can run complex software, Store relatively large amounts of data
● Many organizations are searching for more cost-effective and simple solutions, because of:
 The complexity of the PC itself, The very advanced operating systems
 The amount of locally installed software
 The performance, availability, and security issues related to all of these aspects
● People are attached to their PCs and the term personal computer is still correct
 Users feel their PC is their personal tool that systems managers should not tamper
with
 This is why the adoption of alternatives like thin clients has never been very
successful

7
Laptops and Mobile Devices
● Most laptops are as powerful as desktop PCs
● They are more "personal" than desktops
 Users can take them home or use them on the road
● Laptops have some disadvantages compared to desktop PCs
● Mobile devices in the context of this course are devices that
connect to the IT infrastructure using wireless public or off-site Wi-
Fi networks
 Smartphone & Tablets
 Cars
 Smart Watches
 Digital Cameras
● Computing power of mobile devices is getting comparable to
desktop and laptop computers
8
Bring Your Own Device (BYOD)
● Most organizations use standard PCs or laptops with a limited set of business software
● Users at home have access to:
 Fast, cool laptops of the brand they like, Tablets and smartphones that allow them to run thousands of highly attractive
apps, fast broadband internet connections that are often faster than the shared network in the office

● A concept called Bring Your Own Device (BYOD) allows people to bring personally owned –
typically mobile devices to the office
 Can be used to access the organization’s applications and data, as well as their personal applications and data

● The BYOD concept creates a conflict of interests:

 To optimize stability of the organization’s infrastructure and security, systems managers need to fully control the end
user device
 The owners of the devices want full freedom
 The user paid for the device (they brought their own device), it will not be acceptable to:
 Have systems managers erase the device (personal data) in case of an incident, or Have personal data visible to the
systems managers

9
Printers
● Printers are used in almost all organizations to
provide paper output.
● Most used printer types are:
 Laser printers, Inkjet printers, Multi-Functional Printers
 Specialized printers like:
 Dot matrix printers, Line printers. Plotters, Thermal printers

● A Multi-Function Printer (MFP) is an office device that acts

as a:
 Printer, Scanner, Photocopier, Fax machine
 Provides centralized document management and production in an office
setting

10
Desktop Virtualization
● Virtualization technologies for end user
devices:
 Application virtualization
 Run applications on an underlying virtualized operating
system
 Virtualized PCs based on:
 Server Based Computing (SBC)
 Virtual Desktop Infrastructure (VDI)
11
Application Virtualization
● Application virtualization is typically implemented in a Windows-based
environment
● The term application virtualization is a bit misleading:
 The application itself is not virtualized
 The operating system resources the application uses are virtualized

● Application virtualization isolates applications from some resources of

the underlying operating system and from other applications
 The application virtualization layer provides the application with virtualized parts of
the runtime environment normally provided by the operating system
 The application assumes it is directly interfacing with the operating system

12
Server Based Computing (SBC)
● Server Based Computing (SBC) is a
concept where applications and/or
desktops run on remote servers
● They relay their virtual display to the
user's device
● Keyboard and mouse information is
processed by the application on the
server
● The resulting display changes are sent
back to the user device
13
Server Based Computing (SBC)
● The user’s device runs a lightweight application (a thin client) that:
 Displays the video output from the server, Fetches the keyboard strokes from the client, Fetches mouse
movements from the client, Sends client input back to the application on the remote server

● SBC requires a limited amount of network bandwidth:

 Only changed display information is sent to the end user device, Only keyboard strokes and mouse
movements are sent to the server

● Advantages of SBC:
 Maintenance (like applying patches and upgrades) can be done at the server level
 The changes are available instantly to all users
 Application configurations are the same for all users

● Disadvantages:
 Graphical properties of the SBC server are used instead of that of the client end user device
 Limitations on the desktop experience (slow response or keyboard lag) are mostly due to network latency
or the configuration of the remote desktop
14
Virtual Desktop Infrastructure (VDI)
● Virtual Desktop Infrastructure (VDI)
is a similar concept as SBC
● In VDI, user applications run in their
own virtual machine
● The hypervisor's primary task is to
distribute available hardware
resources between VDI machines on
a physical machine

15
Virtual Desktop Infrastructure (VDI)
● With VDI, each user has exclusive use of the operating system, CPU,
and RAM
 SBC users share these resources
 VDI enables applications and operating systems to run next to each other in
complete isolation without interference
● VDI tends not to scale well in terms of CPU resources and storage
IOPS
 Each client uses an entire virtual machine
 A 'Logon storm' occurs when many virtualized systems boot up at the same
time
 Logon storms can partly be prevented by pre-starting a predefined number
of virtual machines at configured time slots
16
Thin Clients
● VDI and SBC both enable the hosting of desktops on central
server farms and use the same protocols to deliver the output of
application screens to users
● Thin clients communicate with the SBC or VDI server
 Hardware:
 Lightweight computers, inexpensive, have no moving parts or local disk drives
 Have no configuration; can be used directly after plugging them into the network
 Easy to replace when one fails
 No regular upgrades or systems management needed
 Software:
 Applications running in a normal client operating system
 Runs on mobile devices like tablets and smartphones
17
Reliability
● End user devices’ hardware is much less reliable than hardware
installed in the data centre
 To keep the cost low
 Designed to last only 3 to 5 years

● Mobile devices like laptops or tablets can get physically damaged

quite easily
 Leading to hardware failures
 Typical failures are hard disk crashes in laptops or screen cracks in tablets
● A failing end user device immediately leads to downtime for a user
 Loss of availability of business functions to the end user

18
Backup
● Backup of local disks is very important
 Most of the work worldwide is first saved to a local disk on
an end user device
 Automated synchronization of local data to a server can be
implemented
 For end users, it should be impossible to disable this
synchronization function
● End user devices should be protected from random
installs of potential bad software by end users
19
End User Device Performance
● Performance of end user devices is in most cases not a big issue
● PCs and laptops:
 Adding more RAM increases the performance more than choosing a faster CPU
 A faster disk – preferably an SSD disk – can positively affect the performance

● Most data processed on a PC of laptop is transferred using the network

 Make sure enough bandwidth is available for each end user device

● Ensure software running on mobile devices is capable of handling low

bandwidth and unreliable connectivity
 End user devices are often used with public wireless networks (like public Wi-Fi, or 3G,4G)
 Technologies like Server Based Computing can help to make mitigate the effect of low
bandwidth

20
End User Device Security

● Securing end user devices is quite a challenge

 They are not located in a locked down data center
 They are spread around offices, homes and client locations
● Some tips:
 Provide users with laptop cable locks to physically lock the laptop to an
unmovable object to prevent theft.
 If end user devices are at the end-of-life, or when they need repair, fully
erase the hard disk first
 Malware protection software like a virus scanner needs to be installed on
each device
 Laptops and PCs can contain a large amount of (business critical) data –
encrypt the full hard disk! 21