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Calhoun: The NPS Institutional Archive Reports and Technical Reports
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Classroom computing using on demand desktop streaming / by Douglas Brinkley. Brinkley, Douglas Monterey, California. Naval Postgraduate School http://hdl.handle.net/10945/650
NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA
Classroom Computing Using On Demand Desktop Streaming 20 May 2010 by Dr. Douglas Brinkley, Senior Lecturer
Approved for public release; distribution is unlimited. Prepared for: Naval Postgraduate School, Monterey, California 93943
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NAVAL POSTGRADUATE SCHOOL Monterey, California
Daniel T. Oliver President
Leonard A. Ferrari Executive Vice President and Provost
This report was prepared in conjunction with research funded by the International Military Education and Training (IMET) Infrastructure funds administered by the Navy International Program Office (Navy IPO). Reproduction of all or part of this report is authorized.
Douglas E. Brinkley, Ed.D. Senior Lecturer, Graduate School of Business and Public Policy
William R. Gates, Ph.D. Dean, Graduate School of Business and Public Policy
Karl van Bibber, Ph.D. Vice President and Dean of Research
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Approved for public release; distribution is unlimited 14. ABSTRACT
Two of the most popular choices for classroom computing are laptop PCs and thin-client devices. Deciding between the two is often a difficult decision because both platforms have their respective advantages. Modern laptops give excellent performance because of their powerful processors and large amounts of memory. Thin-clients reduce maintenance costs through centralized configuration management. The Naval Postgraduate School is achieving the advantages of both platforms by employing a new technology called On Demand Desktop Streaming (ODDS). ODDS allows the school to maintain all of the laptop software, including the operating system, on a network server. The internal hard drives of the classroom laptops can even be removed to provide a near zero maintenance workstation environment. This paper describes the school’s experiences with stand-alone networked PCs, thin-clients, and the new ODDS system in a classroom setting. 15. SUBJECT TERMS
Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39.18
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Abstract Two of the most popular choices for classroom computing are laptop PCs and thin-client devices. Deciding between the two is often a difficult decision because both platforms have their respective advantages. Modern laptops give excellent performance because of their powerful processors and large amounts of memory. Thin-clients reduce maintenance costs through centralized configuration management. The Naval Postgraduate School is achieving the advantages of both platforms by employing a new technology called On Demand Desktop Streaming (ODDS). ODDS allows the school to maintain all of the laptop software, including the operating system, on a network server. The internal hard drives of the classroom laptops can even be removed to provide a near zero maintenance workstation environment. This paper describes the school’s experiences with stand-alone networked PCs, thin-clients, and the new ODDS system in a classroom setting.
Keywords: Classroom Computing, On Demand Data Streaming, ODDS, Instructional Technology
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About the Author Douglas E. Brinkley is a Senior Lecturer and Director of Instructional Technology for the Graduate School of Business and Public Policy at the Naval Postgraduate School, Monterey, California. He is also a retired US Navy Supply Corps Officer with a subspecialty in computer systems management. During his last two tours on active duty he served as Force Information Systems Officer for Commander, US Naval Air Forces Atlantic Fleet and as Officer In Charge of the DISA Information Processing Center, Guam. Dr. Brinkley earned his Bachelor’s degree in Economics from Excelsior College, a Master of Science in Information Systems from Naval Postgraduate School, and an Ed.D. in Instructional Technology from Nova Southeastern University. Dr. Douglas E. Brinkley Senior Lecturer Director of Instructional Technology Graduate School of Business and Public Policy Naval Postgraduate School Monterey, CA 93943-5000 Tel: 831-656-2771 E-mail: [email protected]
Advantages of the ODDS Architecture ............................................... 15
Disadvantages of the ODDS Architecture .......................................... 16
Findings and Conclusion ........................................................................... 17
List of References.................................................................................................. 19 Initial Distribution List ........................................................................................... 20
List of Figures Figure 1. GSBPP Thin-Client Classroom ................................................................... 7 Figure 2. Close up of monitor mounted thin-client...................................................... 7 Figure 3. On Demand Desktop Streaming Operation (Citrix Systems, Inc.2009) .... 14
Introduction In 2004 the Graduate School of Business and Public Policy (GSBPP) at
the Naval Postgraduate School built a prototype smart classroom seating 45 students with networked laptop PCs at every seat. Infusing computer technology into the traditional lecture based classroom proved to be a resounding success and that classroom quickly became the most frequently requested room every quarter. Faculty reported they could cover up to 20% more material in the same amount of time. The improved efficiency was the result of the instructor being able to optimize their instruction by using computer based tools whenever it was appropriate rather than having to wait for a specific hour of the week when they had access to a computer lab. In the past, courses would be divided between lecture based classroom time and one or two hours per week of computer lab. Another instructional example is the use of the Internet to access on-line databases such as federal budget information in order to bring current budget issues into the classroom at the same time they are being addressed by the government. Thanks to the concurrency of access to the data and the issues at hand, the relevance of the materials becomes immediately apparent to the student (Doyle, 2010). Beyond the instructional advantages, research has also shown a significant increase in the level of student interaction when computer mediated communications are incorporated into the education process (Brinkley, 2003).
The success of the prototype project generated a demand to install computers for every student in as many classrooms as possible. Unfortunately for GSBPP and most other schools, the goal of procuring and maintaining enough computers to satisfy the demand was impractical due to limited resources. Even when funds exist for the initial hardware procurement, labor and management costs can account for up to 80% of the total lifecycle costs (Marko, 2009). The school tried to reduce these extended lifecycle costs through the use of thin-client/server based devices which promised more efficient centralized configuration management.
Unfortunately the performance of the thin-client
devices was never as good as the stand-alone PCs and thus the school continued to use a mix of the two architectures in its different classrooms. This paper will describe the lessons learned from both the thin-client and stand-alone computer implementations and also report the school’s findings on using a new technology called On Demand Desktop Streaming (ODDS).
Setting The Graduate School of Business and Public Policy is one of four
academic schools that make up the Naval Postgraduate School (NPS). NPS is located in Monterey, California and was established in 1909 to serve the advanced educational needs of the United States Navy. It has since been expanded to support students from other the other U.S. military services and foreign countries as well. The total student population consists of approximately 1,500 students coming from all branches of the U.S. defense community and the military services of more than 25 allied nations. NPS is a well diversified, fully accredited graduate school with a proud history of academic excellence. This paper focuses on the classroom technologies employed by the Graduate School of Business and Public Policy (GSBPP). Classrooms within GSBPP are designed to accommodate an average of thirty to forty students. Continuously seeking to improve, GSBPP evaluates and considers the adoption of new technologies that could further improve teaching effectiveness and efficiency.
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Stand-alone Computing Environment As stated earlier, GSBPP began installing computers in its classrooms in
2004. The initial implementation consisted of stand-alone laptop computers at every seat. Several classrooms continue to use the stand-alone architecture today. In this usage the term stand-alone simply means the computers can operate independently because each machine stores its operating system and application software on its own internal hard drive. The computers were also connected to the school’s network via 100 Megabit Fast Ethernet connections. The network connection allowed the systems to access the school’s intranet and the Internet. The standard configuration includes a dual core processor, 2 Gigabytes of internal memory, and the Windows XP Professional operating system. Thanks to their fast processors and abundant internal memory, the stand-alone laptop PCs provided the best performance of all the options available. Unfortunately this architecture has the greatest lifecycle costs as it requires the most man-hours to maintain. Technicians must update each individual laptop with security patches, anti-virus software, and other software changes. With a fixed amount of technology support and a growing need to expand the number of computers installed in the classrooms, the school was forced to consider other alternatives that promised more efficient configuration management.
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Thin-Client/Server Based Computing Environment
The need for more efficient configuration management led to the use of thin-clients in the classroom starting in 2006 (figures 1 and 2).
Figure 1: GSBPP thin-client classroom
Figure 2: Close up of monitor mounted thin-client Computer technology has come full circle with the rebirth of thin-client computing. Thin-clients were in fact part of the original concept in computing 7
with large mainframes servicing simple client terminals that provided users with nothing more than keyboard and monitor interfaces. The popularity of the desktop PC soared in the late 1980’s and 1990’s nearly erasing thin-client technology from the computer revolution. However growing security and management concerns leads many organizations to rethink their computing strategy. At the same time increased network bandwidths and advances in server based technologies made thin-clients a viable option again. Today’s thinclient devices continue to use a server-centric model where all of the data and applications are stored on the server. The server also executes the various applications and the thin-clients function as the remote keyboard and monitor. This differs from the networked PC model where the data may be located on a network server but the applications are stored and executed locally on the PC. A. Thin-Client Advantages Arguably the greatest advantage of thin-clients over traditional PCs is the lower total cost of ownership. This includes both the original acquisition cost and the life cycle maintenance and support costs. Thin-client acquisition costs are normally just 50-60 percent of a full workstation (Williams, 2005). Even more significant are the savings realized by the reduction in support and maintenance costs. The Gartner Group (1999) reported thin-client desktops could cut life cycle costs by 80 percent. Cost savings are not the only advantages of thinclient desktops. Williams (2005) and Romm (2006) cite the following additional benefits:
Longer Service life – With no moving parts and no built-in obsolescence, thin-clients may last up to ten years. Reduced Power Consumption – With no need to power internal devices and fans, thin-clients consume only ten percent of the amount of electricity needed to run a PC. Easier Configuration Management – Thanks to the server-centric environment, applications, updates, and security patches only have to be installed on the server vice individual PCs. Improved Security – The server-centric environment eliminates the need to install anti-virus software on the client PCs and allows system administrators to focus their protection efforts on just the servers. Storing everything on the servers also allows for more efficient and comprehensive backup procedures since there is nothing to backup on the end user stations. Reduced Space and Weight Requirements – Many thin-client terminals are about the same size and weight as a paperback book. This could be a significant benefit in space constrained environments. Reduced Noise Pollution – With no fans or other moving parts, thin-client terminals produce virtually no noise at all. This could be an important consideration for classroom and library installations. Inherent Theft Deterrence – Because the thin-client us useless without the server they are much less desirable to thieves than PCs and therefore less likely to be stolen.
B. Thin-Client Disadvantages Thin-clients have some significant disadvantages that must also be considered. Perhaps the greatest of these stems from the same server-centric mode of operation that provides so many of the benefits. The server-centric architecture also means server-dependency. If the server itself goes down or network access to the server is interrupted, the thin-client station is rendered useless. Other disadvantages noted by the British Educational Communications and Technology Agency (Becta, 2004) include: Reduced Software Compatibility – Some applications are not network compatible and will not function unless they can be loaded onto end user PC hard drives. Because these types of applications are incompatible with the thinclient environment, alternative applications may have to be identified and purchased. Inflexibility – If a particular application or add on has not been installed on the server, it is not possible for a user to download it to the client machine. End users are totally reliant on server administrators for software installations and updates. Higher Bandwidth Requirements – As thin-clients require nearly all processing to be carried out on the server, there is considerably more network traffic between the clients and the server. Inadequate bandwidth will result in poor performance for the end user. Reduced Peripheral Options – Most new thin-client devices include USB ports but the end user is not able to add device drivers. Therefore while the thin10
client station may recognize common peripherals such as flash drives and other plug and play devices, peripherals requiring a driver such as a printer or PDA would not be supported. Poor Multimedia Performance – Recent advances in thin-client processing and server technology have helped alleviate this to some extent, however real time full motion video with sound continues to be problematic on a thin-client network. C. Classroom Experience with Thin-Clients GSBPP’s first hand experience using thin-clients in the classroom from 2006 through 2008 confirmed the advantages and disadvantages cited above. Unfortunately the advantage of “easier configuration management” was not quite what was hoped for. The Wyse model S90 thin-client chosen used XPe for its operating system. XPe stands for Windows XP Embedded. This scaled down version of the standard Windows XP operating system provided excellent “plug and play” compatibility with devices like student’s thumb drives. Unfortunately it also required frequent software patches like any other Windows OS. Wyse provided software which was supposed to make pushing the patches onto the thin clients from a server possible. However, even with Wyse technical support on the phone, it was very difficult to make it work and most of the time the technicians had to install the patches individually while logged on locally at each thin-client. The disadvantage of “poor multimedia performance” was also frustrating for the students. Several courses included some web based instruction that utilized steaming video. The performance of the thin-clients was 11
so poor in this area that these courses had to be rescheduled to classrooms that still used stand-alone computers. Because of these limitations GSBPP kept looking for other alternatives that would provide centralized configuration management and better performance.
On Demand Desktop Streaming In 2008 the school’s network infrastructure was upgraded to Gigabit
Ethernet which transmits 1,000 megabits per second. This ten fold improvement over the previous 100 megabit Fast Ethernet opened the door to new technology options, specifically On Demand Desktop Streaming (ODDS). ODDS allows networked PCs to receive all of their software programs, including the operating system and applications from a network server. Dell, Inc. gave an informal demonstration with one server and four laptop PCs. The laptops were loaded with the school’s standard Windows XP Pro operating system and a full suite of applications including Microsoft Office and other programs used for statistics and modeling. First the laptops were run in their stand-alone network PC mode and several benchmark measurements were taken as performance reference points. The BIOS settings of the laptops were then modified to instruct the machines to boot off of the network and the laptop hard drives were removed from the systems. The laptops were then rebooted over the network. After the startup was completed, the look of the desktop was exactly the same as it was when the laptops were using their internal hard drives. More importantly, the performance of the laptops operating in ODDS mode was almost indistinguishable from the stand-alone networked PC mode. Even video streaming applications, which could not be used at all with the previous thin-client devices, worked flawlessly. In 2009 the school replaced thirty six thin-client devices in one of its classrooms with diskless laptops using ODDS. 13
A. ODDS Setup Figure 3 illustrates the three major steps necessary to setup up the ODDS environment. The first step is to create an image of a model workstation, including its operating system, applications, and configuration. This includes all of the hardware drivers specific to the exact model of workstation that will be used. In this case, Dell model E6500 laptops were chosen as the classroom workstation devices based on portability, performance, and compatibility with the ODDS environment. The complete image is then stored on a Citrix provisioning server. For GSBPP this was a Dell PowerEdge model R710 server. The laptops are then configured to boot over the network and the image is streamed to the laptop on-demand. It is important to note that only a portion of the image is streamed to the workstations at any point in time dependent upon what the workstation requires/demands for operation.
Figure 3: On Demand Desktop Streaming Operation (Citrix Systems, Inc. 2009) 14
B. Advantages of the ODDS Architecture Easier Configuration Management – Storing all of the software on the provisioning server eliminates the need for workstation hard drives and thus also eliminates 90% of workstation trouble calls. Updates to the OS and application software are only made to the master image. The changes are then automatically distributed to all of the workstations the next time they startup. Reduced Risk – Multiple images can be stored on the provisioning server at the same time. Administrators can roll-back to an older image if a new image does not function correctly. Risks are further reduced by the inherent elimination of viruses and malware infecting the workstations. Nothing is stored on the workstations and the streamed images are read-only which means a fresh, uncorrupted image is loaded at each startup. End User Flexibility – Another advantage of being able to store multiple images for a given workstation is the flexibility of using different operating systems and applications for different users. Administrators can easily redirect a workstation at startup to any image stored on the provisioning server. Improved Security – Storing all of the software and data remotely in the data center reduces the possibility of theft or loss of data due to a hard drive failure. Data centers usually employ more stringent access control and fault tolerant storage techniques than would be used at the end user’s workstation. Improved Performance – Because the software is streamed and executed on the workstation, the performance seen by the end user is comparable to a stand-alone system. Today’s workstations benefit from much more powerful 15
processors and larger amounts of internal memory than typical thin-client devices. C. Disadvantages of the ODDS Architecture Higher Bandwidth Requirements – ODDS is marketed to be compatible with 100 megabit/second Fast Ethernet. However, classroom testing determined there was a significant reduction in performance when downshifting from Gigabit Ethernet to Fast Ethernet. Network/Server Dependency – Removing the software from the local workstation makes them inoperable during any network or server down time. Increased Server Expense – The need for a Citrix provisioning server with high speed data storage adds another expense beyond normal data center operations. The implementation vendor, Dell, strongly advised against consolidating the provisioning server with other servers in a virtual environment.
Finding s and Conclusion As of April 2010, the school’s ODDS classroom had been operational for
six months. During this time each of the advantages and disadvantages listed above were confirmed. The primary goals of achieving a more efficient centralized configuration management environment and improving end user performance were clearly met. The increased server expense is expected to be mitigated by the lower life cycle costs of maintaining the workstations. GSBPP considers the ODDS implementation a success and plans to expand its use to other classrooms in the near future.
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List of References Becta, (2004). Thin-client Networking, [On-line]. Available: http://board.becta.org.uk/content_files/corporate/resources/technology_an d_education_research/thin_client.pdf [2006, April]. Brinkley, D. (2003). The Effect of Computer-Mediated Communications on Graduate Student Interactions. In G. Richards (Ed.), Proceedings of World Conference on E-Learning in Corporate, Government, Healthcare, & Higher Education 2003, (pp. 1536 – 1539). Chesapeake, VA: AACE. Citrix Systems, Inc (2009). Citrix Provisioning Services Technical Overview, A PowerPoint presentation provided by the Citrix Marketing Department. Doyle, R. (2010). Asynchronous Online Graduate Public Policy Education: The Use of Public Databases to Engage Students and Advance Learning, Proceedings of Global Learn Asia Pacific 2010 – Global Conference on Learning and Technology, Chesapeake, VA: AACE GartnerGroup (1999). Thin-Client Desktops Cut Support Costs by 80 Percent, [On-line]. Datapro Reports. Available: http://www.gartner.com/5_about/press_room/pr19990518a.html [2006, March]. Marko, K. (2009). Creating a PC Lifecycle Policy. In Processor, 31(13), 34 [2009, April 24] Romm, D. (2006). It Pays to be Thin. Library Journal, 131(2), 34-36. Williams, R. L. (2005). Thick or Thin? Evaluating Thin-clients in Sustaining Library Technology. Library Hi Tech News, 7, 9-14.
Initial Distribution List 1. Defense Technical Information Center 8725 John J. Kingman Rd., STE 0944 Ft. Belvoir, Virginia 22060-6218
2. Dudley Knox Library, Code 130 Naval Postgraduate School Monterey, California 93943-5100
3. Research and Sponsored Programs Office, Code 41 Naval Postgraduate School, Monterey, CA 93943
4. William R. Gates Code 810 (GB) Naval Postgraduate School, Monterey, CA 93943
5. Stephen Mehay Code 810 (GB) Naval Postgraduate School, Monterey, CA 93943
6. Douglas Brinkley Code 810 (GB) Naval Postgraduate School, Monterey, CA 93943