Jose Carlos Norte discusses the limitations of traditional VDI approaches that involve virtualizing entire desktop environments. He proposes a more efficient "hybrid virtualization" approach using eyeOS's cloud desktop solution, which provides a centralized web-based desktop environment under a company's control. This allows applications to be selectively virtualized using Citrix XenApp when needed, while other applications can run locally or as web apps, optimizing software licensing and server resource usage compared to traditional VDI.

1. White Paper - Version 1.0 eyeOS - January 2012
Hybrid virtualization:
optimal management of a
company’s IT resources
How Cloud Computing can
revolutionize the virtualization of desktops in the work place
Jose Carlos Norte
eyeOS CTO

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Contents
1. Starting point: Thick Client: the dominant model
2. The turning point: a post-PC world with an abundance of bandwidth
3. Virtual Desktop Interface (VDI): the emerging alternative
4. Virtualization of applications: the second iteration
5. Identifying the underlying problem
6. Hybrid virtualization: the most efficient solution
7. Hybrid virtualization put into practice
8. Conclusion
Summary
Jose Carlos Norte, creator of the software and CTO of eyeOS since it was founded in 2005, discusses
the limitations of traditional VDI and puts forth a more efficient alternative based on centralized control of
the desktop thanks to eyeOS’s Cloud Desktop solution combined with virtualization applications such as
XenApp from Citrix.
Tickets Virtualization eyeOS cloud desktop Citrix XenApp VDI Windows

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1. Starting point: Thick Client: the dominant model 2. The turning point: a post-PC world with an
abundance of bandwidth
To have a better understanding of what eyeOS is and
what it can be used for , we first have to understand
the need that it attempts to satisfy, considering that
this need is derived from the current state of IT OS
systems and their limitations.
As a consequence to the major advances in
telecommunications and connectivity in general, as
well as the arrival of new devices at the work place,
such as smartphones and ipads, the IT departments
within organizations have had to question the ‘Thick
Client’ model. They have realized that what users
really need is not so much an isolated computer that
manages all the desktop applications locally, with
‘windows’ into other computers, but, rather a logical
working environment, separated from the underlying
hardware, that provides the user with access to the
Up until relatively recently, the widespread roll out files and applications they need.
and adoption of the PC in the workplace has been
based on the ‘Thick Client’ model. This model Why?
assumes that each individual computer has all
necessary software locally installed as well as a local • The prohibitive costs of user support (Help Desk)
hard drive to store information. resulting from the complexity of the incidents
caused by the number of possible hardware and
Within this context, the computer is an autonomous software combinations present in organizations.
unit, independent of its environment. To address • The license upgrade cost of each PC.
the need to share information, computers were • Lack of control over the applications installed
connected via networks, whereby the units locally by the user whether for professional
continued to be stand-alone and independent, purposes or not, with the associated risk of
albeit with access ‘windows’ within which they can viruses or PC malfunctions.
communicate with other computers using client- • Computer hardware failures that cause data to
server software, such as file-sharing. be lost. If the computer fails, then users no longer
have a work environment, as the computer itself
This model spread throughout the world, and millions is the environment, and they potentially have to
of companies now have their work stations set up wait for another computer to be prepared in order
according to this model. to continue working, a process that can take
hours or even days.
• Applications are increasingly diverse (web,
transactional, Unix, Windows, etc.), and users
must be able to use them all irrespective of the
underlying architecture.

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• Excessive time to prepare new work stations for
every new employee.
3. Virtual Desktop Interface (VDI): the emerging
alternative
Ever since IT industry professionals began to
comprehend the limitations of having the desktop
environment concept connected to the PC concept,
they have tried several strategies to disconnect them
into separate and independent components.
A relatively simple approach that was designed
to tackle this issue was to run multiple Windows
sessions on a company’s server, whereby users
would connect to these sessions remotely and then However, no matter how much these particular
use them to access their applications and data. In protocols are perfected, working with a remote
this way, the local operating system is irrelevant, desktop has its down sides, both in terms of user
and the data is located on the server. Users can experience – system performance issues are
connect to that Windows session from any terminal inevitable depending on the number of simultaneous
and work away. The process achieves PC <-> work sessions running – and in terms of server scalability.
environment independence.
The consequence of the structural limitations of a
In order to ensure that there is a Windows session solution of this type, such as CITRIX’s XenDesktop,
available for every individual user, virtualization is that the financial costs of software licensing as
technology must be used. Virtualization consists of well as the infrastructure necessary to run a remote
simulating a PC within another computer, such that Windows session for each user, tends to cancel out
multiple operating systems can be run simultaneously the benefits associated with centralized management
on a single physical server. of the client desktop. Therefore, this solution is
not universally appropriate to all company types
A secondary challenge is how to send the image of or environments, and is much more suited to large
the Windows session running on the server to the companies associated with high volumes of repetitive
user’s PC and make it possible for the user to use the transactions that are capable of assuming the high
key board and mouse to interact with their particular initial costs of deployment.
Windows session.
This technology is called Virtual Desktop Interface
To be able to send the image of their Windows (VDI). VDI has been a failure in many aspects due
session to the user, running with its wallpaper, to the aforementioned reasons and it has really only
icons, etc., certain protocols are used, that have been feasible in the banking sector, the public sector
been specifically designed to consume minimum and similar organizations where there are large IT
bandwidth. Tens of millions of dollars have been budgets.
invested in these protocols, and currently one of the
most advanced is ICA.

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4. Virtualization of applications: the second iteration The main problem with VDI as an approach is that
Microsoft Windows combines two environments at
Citrix, seeing the aforementioned problems, decided the same time: an operating system that can house
to create a new product called XenApp. XenApp, applications such as Microsoft Office, and a desktop
unlike its big brother XenDesktop, does not project an that defines the user’s interaction with the PC. With
entire Windows application to the user’s terminal, but VDI, there cannot be a separation between the two
rather it projects single applications on demand. The environments: even the most basic of the user’s
user continues to have his local Windows operating actions are virtualized en bloc and are run remotely
system, but the applications they use, MS Office (for on their desktop, such as moving or minimizing
example) are abstracted from the local environment a window. They are actions that, when executed
and are in fact hosted on a remote server. This remotely, consume server resources as well as
approach has the advantage of not requiring a copy bandwidth, when they could be executed locally more
of MS Office, for example, to be installed locally efficiently.
on each machine. This allows for more efficient The arrival of new devices with innovative user
centralized maintenance of the application. Licensing interfaces (varying screen size, new operating
costs are not necessarily impacted as in our example systems) further complicates the task of sending
the software license is paid per user, not per remote images in such a way as to ensure that the
installation. user always has a satisfactory experience. However,
all new devices have at least one point in common:
XenApp has however, a major deficiency, which goes they have a considerable amount of computing
back to its original design. The IT administrator is power. The available computing power should be
no longer in control of the user desktop. In order used to relieve the server of performing tasks that are
to minimize VDI costs the virtualization process not vital to either the management of applications or
becomes more selective in terms of deciding which to independence between the environment and the
applications are virtualized and which ones run device. Pushing these tasks to the server makes no
locally. Moreover, using XenApp to virtualize only sense and is expensive: CPU and RAM cycles end
certain applications on a remote server, with these up being paid for twice over.
applications being ‘projected’ onto the local operating
system, does not resolve the initial requirement Moreover, from a central perspective, infrastructure
around which Citrix revolves: disconnecting the work has limits in terms of vertical scalability: a server
environment from the physical access device. certainly cannot grow infinitely. Very soon, more
users will be added and a second server will be
needed in order to run so many Windows session
5. Identifying the underlying problem. and then a third and a fourth. Subsequently, when a
certain threshold is reached, communication between
each server becomes critical, and latency issues will
have to be tackled: it will then be time to install an
expensive fiber optic network, and the infrastructure
? thus continues to grow, while the users’ terminals
have their CPUs under employed.
One strategy that might seem attractive to tackle this
problem is to keep running the Windows session on
the server, but push some parts of the rendering and

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computation to the local terminal. the server: operations such as moving a window
or working with files do not require virtualization;
The problem with this approach is that, ultimately, operations are only being done through the web
making the work station independent from the on the server.
local computer is not simply a question of taking
it as is – with everything bundled together and Within the system, direct accesses and resources
connected – and sending it to the server, and then of all kinds can be integrated, such as the
‘projecting’ it over the network to the client PC. following:
del renderizado y computo al terminal local.
• eyeOS native web application launchers.
• External or third-party web application
6. Hybrid virtualization: the most efficient solution launchers, hosted on the client’s servers or
SaaS.
The only real way to make the work station • Launchers of local desktop applications, such
independent, manage it, and make it available as Microsoft Office or AutoCAD, which are
from a central point entails decoupling the desktop installed on the user’s access terminal.
concept from the operating system concept. • Launchers of virtualized applications running
on a server using XenApp.
eyeOS proposes that users work in a web-
based environment. The proposed environment
is a highly advanced web page that recreates 7. Hybrid virtualization put into practice
the entire work environment, with the look of a
desktop such as the one that can be found in MS
Windows.
Based on this environment as a starting point,
a company can determine the applications
that it introduces on to the desktop. Out of the
box eyeOS includes some purely web-based A good way to understand eyeOS is to recreate an
applications that are seamlessly integrated on example using eyeOS and Citrix.
the desktop, that are in fact an added value of the
platform and straight away provide some work By combining XenApp and eyeOS, a company
related functions (calendars, file management, only uses virtualization when it wants to run
contact list, collaborative work, etc.). certain remote applications (that’s what XenApp
consists of), but it does not lose control of the
However, the real power of eyeOS lies in the complete environment, given that the desktop is
possibility of building an entire work environment centralized and is web-based. What we’ve done is
around a web-based environment. to cease providing a virtualized Windows desktop
from a server, and we’ve started providing a
The eyeOS environment can be adapted and working desktop controlled by the company, which
modified according to the client’s needs, and it is made available through the web much more
can be adapted to new mobile devices. And since “thinly”.
it is also very thin, given that it is web based, it
does not require constant communication with

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Then the applications or resources that are made This ability to support such varied behaviors
available within that environment can be decided depending on the user profile gives the system a
upon by the company or organization that installs flexibility that is at the core of eyeOS’s entire reason
eyeOS. for being. A company can continue to use MS Office
software licenses at work stations that have this
eyeOS allows this concept to be taken to very software already installed for all employees who
advanced levels and allows an administrator to need mobility, meanwhile optimizing the number
discriminate between user profiles and provide of concurrent users of virtualized applications
behaviors according to a company’s needs and by offering a preview. The savings in licenses is
resources, something completely new from eyeOS. immediate.
A clear example of this is the following: what happens With XenApp, strange situations can often arise,
when a user double clicks on a Microsoft Word such as having a Windows session running on top of
document? another Windows session through XenDesktop, and
within the latter, you could be working with MS Office,
The administrator has the authority to predefine when the underlying Windows session also has MS
the sequence, per user profile, within a range of Office.
possibilities:
In eyeOS, users can access the web desktop from
anywhere and from any device. It is an entirely thin
approach, and the consumption of applications
adapts to a company’s needs and the profile of each
• Download. user.
Open the local Word application.
The classic VDI cannot handle the problem in this
• Web preview. way, given that in the end it only projects either a
part of a Windows session or all of it, but it does not
• AOpen Word running on a remote process any file on its own or make decisions about
server and made available via the user’s actions within the desktop. This is because
XenApp. the desktop is not controlled by Citrix, it is controlled
by Microsoft Windows, and for Citrix it is only an
• Thin web preview, and in the case image sent by wire.
of editing, click on the launch edit
button from: In addition to being a desktop, eyeOS is a
platform that enables the existence of the
the local application desktop. This platform includes file management,
or the XenApp application. user management, authentication, etc. Some of
the platform’s components can connect to the
• Open the local application if it is organization’s resources. This is the case with
available or use XenApp if it is not. regards to authentication, which can be auto-
managed by eyeOS using its own database or it can
be consumed from an Active Directory.

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8. Conclusion will be web-based applications or even local applications.
This flexibility allows optimized management of software
Virtualization with the remote projection of applications licenses, and it radically reduces CPU consumption by
is not an incorrect approach. What is incorrect – or more central servers, without sacrificing control over a user’s
accurately, what is inefficient – is the virtualization and experience by the administrator.
remote projection of complete desktops.
Therefore, eyeOS should be seen as a platform that
eyeOS acts as a web desktop under the centralized connects to a company’s resources, thereby becoming
control of a company, thereby bringing together integrated within an organization (resources, file servers,
resources and managing access to the appropriate etc.), that provides a web-based work environment,
applications. In certain cases, the applications will be unified and centralized on a company’s servers or
virtualized from a central server, and in other cases they wherever a company decides to install it.