A DISCUSSION OF THIN CLIENT TECHNOLOGY FORCOMPUTER LABS

Jesus Martınez-Mateo, Susana Munoz-Hernandez and David Perez-ReyFacultad de Informatica, Universidad Politecnica de Madrid, Campus de Montegancedo, Madrid, Spain

Keywords: Thin client, e-Learning, Computer lab.

Abstract: Computer literacy is not negotiable for any professional in an increasingly computerised environment. Ed-ucational institutions should be equipped to provide this new basic training for modern life. Accordingly,computer labs are an essential medium for education in almost any field. Computer labs are one of the mostpopular IT infrastructures for technical training in primary and secondary schools, universities and other ed-ucational institutions all over the world. Unfortunately, a computer lab is expensive, in terms of both initialpurchase and annual maintenance costs, and especially when we want to run the latest software. Hence,research efforts addressing computer lab efficiency, performance or cost reduction would have a worldwiderepercussion. In response to this concern, this paper presents a survey on thin client technology for computerlabs in educational environments. Besides setting out the advantages and drawbacks of this technology, weaim to refute false prejudices against thin clients, identifying a set of educational scenarios where thin clientsare a better choice and others requiring traditional solutions.

1 INTRODUCTION

Traditional education has been hampered by the dif-ficulties inherent in information and communicationtechnologies (ICT). Nowadays, modern educationfaces a new challenge: the use of technology in theclassroom. Concerning these new educational chal-lenges, probably one of the most popular is related toimproving computer lab performance. Note that con-sidering the number of institutions that have to dealwith these infrastructures, any advantageous proposalwill have a worldwide repercussion.

There are a set of well-known problems that ed-ucational institutions must address when using com-puter labs. The main obstacles are usually related toeconomic issues. Some institutions do not even havecomputer labs due to unaffordable costs. The equip-ment and the installation of a new computer lab isvery expensive. Moreover, both software and hard-ware maintenance is a sustained cost over time. Soft-ware and hardware evolve daily at a speed that mostinstitutions are unable to keep pace with. Thus soft-ware and hardware upgrades especially are an ex-pense that many institutions are unwilling to pay.

Thin client technology can be used to overcomesome of these problems. For instance, this technologyis an especially interesting option when upgrading an

educational computer lab, but it is not widespreadin these scenarios probably due to historical preju-dices. An excessive triumphalism by supporters ofthin client technology, claiming the many advantagesof this technology sometimes rightly or wrongly butusually without proper justification, may have led tothe early dismissal of thin client technology by manyprofessionals. It has often been relegated to an imma-ture technology status. However, today there are so-lutions based on thin client technology that are simpleto use, and after many years of development and evo-lution are highly reliable, which could be a very in-teresting option in some specific scenarios. Some ofthese solutions are theLinux Terminal Server Project(LTSP) project1, especially designed for Unix-basedsystems, orLan Core2, a project originally focusedon the use of thin clients on Windows systems.

In this paper we summarise the main characteris-tics of thin clients (Section 2), explicitly stating theirstrengths and weakness related to the educational en-vironment (Section 3). From this information we haveidentified a set of scenarios (Section 4) where the usethin client technology is a good option, and somecounter examples.

1http://www.ltsp.org2http://lancore.sourceforge.net

119Martínez-Mateo J., Munoz-Hernandez S. and Pérez-Rey D. (2010).A DISCUSSION OF THIN CLIENT TECHNOLOGY FOR COMPUTER LABS.In Proceedings of the Multi-Conference on Innovative Developments in ICT, pages 119-124DOI: 10.5220/0002962901190124Copyright c© SciTePress

Figure 1: In a thin client network, all clients are continu-ously connected to a common server in a centralised archi-tecture. For each connection the server sends the desktop tothe client computer (the thin client). The user works usinga remote desktop session.

2 THIN CLIENT TECHNOLOGY

From the very beginning of computing, around the1950s, early computers had to be shared by multi-ple users on economic grounds. Mainframes, mainlyknown for their large size and priced according by,evolved towards the interaction of a single computerwith multiple users. A few years later the first termi-nal appeared: This was an specific device connectedto the mainframe enabling multiple users to accessand share computing resources through batch proces-sing. The early terminals, today known as consoles,worked in text mode only, and were connected viaserial lines. Therefore, a primitive type of general-purpose device working much like a thin client wasthere way back when the main commercial computersfirst came on the scene.

Console terminals evolved gradually and continu-ously for years until the advent of the personal com-puter (PC) in the 1980s. Physical terminals were thenimmediately replaced by PCs equipped with terminalemulation software. Not only were PCs a substitutefor the old terminal devices, but they also marked aprofound change in the computing architecture. Forthe first time, the client (i.e. the PC) had its own pro-cessing capacity, leading to the client and server di-vision. It was also a turning point for terminal com-puting, where terminals became known as thin clients

and they were no longer connected to a central com-puter directly, but via a network. New graphical op-erating systems, including the new Unix-based sys-tems (e.g. Linux), introduced the new desktop con-cept. The client side in a thin client solution had to bemodified to be adapted to graphical devices (see Fig-ure 1), new user interfaces, the mouse and other newinput and output devices.

Because of everything discussed above, today it isnot possible to find a primary reference introducingthe new concept of thin client, terminal, or disklessdevices in computing. However, there can be no doubtthat thin client technology has been always present incomputing, sometimes going by a different name orterminology, running on primitive or highly evolvedhardware, even supported by entirely different oper-ating systems, using batch processing, multitasking,and other hardware and software sharing strategies.

2.1 Thin Client Benefits

Thin client technology can make a network admin-istrator’s job easier for three main reasons: it iseasy to manage, easy to secure and easy on the bud-get (Romm, 2006). An explanation of each one ofthese benefits follows:

1. A thin client network is easy to manage and main-tain thanks to its centralised set-up and support. Itsimplifies troubleshooting, network management,and monitoring among other things.

2. Security is provided intrinsically by the architec-ture of a thin client solution. Input devices suchas local Universal Serial Bus (USB) ports are eas-ily disabled, thus avoiding a common source ofviruses. The integration of firewall functional-ity in every computer in the network (i.e. a dis-tributed firewall) is possible by just configuring afirewall on the server (Ioannidis et al., 2000).

3. The use of thin client technology is low cost interms of hardware (see Figure 2), software (justone licence for the server), set-up and mainte-nance (see Figure 3).

Points one and two are related to the fact that thereis only one processor and point three is related to thesimplicity of the thin client technology. In the contextof this paper there is one property of thin client tech-nology that should be emphasised: a thin client has noneed of high processing capacity. Note that it will notrun anything apart from the hardware and softwareneeded to properly visualise the graphical user in-terface. Accordingly low-performance hardware (i.e.out-of-date computers or “ancient hardware”) could

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0 5 10 15 20 25

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Thin Client

PC

Figure 2: Evolution of the price (vertical axis in euros) perunit (PC or thin client) according to the number of installedworkstations (horizontal axis). This estimate has been cal-culated assuming the following costs: PC 600 EUR, thinclient 400 EUR, and server 1000 EUR; with an incremen-tal discount (n× 0.5%) depending on the number of unitspurchased.

be used to build a thin client. Considering these bene-fits, thin clients are an attractive technology for insti-tutions with old computers, budget concern and lim-ited maintenance staff (i.e. more than 80% of the ed-ucational institutions in the world, most of them indeveloping countries).

2.2 Green Computing

Reducing energy consumption is an attractive goal notonly due to increasing energy costs, but also fromthe standpoint of natural resources and environmentalconservation. There are many reasons for implement-ing green IT systems, and hardware that is specificallydesigned for thin clients seems to fit in perfectly here(UMSICHT, 2008).

In a comparison with other alternatives that havesimilar possibilities to thin clients on other counts,thin client technology has an important point in favourof its aptness for green computing.

3 STRENGTHS ANDWEAKNESSES

Probably the main feature of a thin client is that usersdo not appreciate any difference from a desktop PCwhen they first come into contact with the device. Thedesktop displayed by a thin client is exactly the sameas one shown by a PC. This property of thin clienttechnology is essential in educational labs and it isone of the strengths of this technology. Using thinclients students can acquire the same skills that theycould learn using PCs because they actually use the

0 2 4 6 8 100

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Figure 3: Estimated hours of maintenance per week (ver-tical axis) depending on the number of workstations (hori-zontal axis), comparing PCs versus thin clients.

same tools and applications (running on the server in-stead of on their own machines).

Another important strength of thin clients is thatmost of the applications used on a PC, such as thoseincluded in an office suite (e.g. Microsoft Officein Windows operating systems or Open Office forLinux) will probably run on a network with thinclients. Similarly, Wikipedia (probably the most vis-ited website on the Internet in academic environ-ments) also has these advantages.

On the other hand, the thin client technology’smain weakness materialises in what are technicallyreferred to as high-motion scenarios (Deboosere et al.,2007). High-motion scenarios include:

• Streaming multimedia: video and audio are al-most prohibitive using thin clients.

• Motion graphics: animations, slide effects, etc.,are processes that are often affected by a desktopvirtualisation.

• Applications requiring a powerful graphics card:everything related to games and 3D rendering.

• Latency-sensitive applications, where the time ittakes an event to reach the client through a net-work is critical.

Hence, thin client technology is not an alternativefor scenarios with these requirements, but it could bean optimal solution in the near future due to severaltechnical developments attempting to overcome theabove weaknesses (Simoens et al., 2008).

4 COMMON ACADEMICSCENARIOS

Each computer-based environment has particular re-quirements that need to be considered to find the opti-mal hardware and software solution. Looking at thin

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clients, some advantages and limitations of this tech-nology will act as detriment or incentive for a thinclient solution. Below we analyse the main academicscenarios regarding thin client suitability.

Note that we have highlighted overlaps among dif-ferent scenarios.

4.1 Computer Labs

As discussed above (Figures 2 and 3) thin clients havean edge in terms of budget and maintenance concernsover PCs in installations from five and eight com-puters respectively. This covers almost all computerlabs in education. Thus a computer lab intended fortraditional computer-based learning may also benefitfrom thin clients if they support the required tools. Aprevious study suggests that most tools used in theacademic environment can be used with thin clients(Brinkley, 2006). The results of this research are con-clusive: of the 45 tools used in this case, only threecould not be used, and there were some minor prob-lems with another three. The rest of tools run cor-rectly using thin client technology.

Technology facilitates student participation andcomputer labs are beginning to be used with this aim(Peiper et al., 2004). Although there are interactiv-ity increments in collaborative environments they aresupported by thin client technology.

4.2 Distance Learning

Distance learning is a relatively modern academic sit-uation in computer-based learning, where ICTs areused to circumvent the boundaries of a physical class-room. This is a wider scenario than the one consid-ered in a computer lab. A range of situations depend-ing on student and professor location are listed below:

• Local students and professors. Traditionalcomputer-enhanced learning to meet today’s ICTliteracy need. This situation is spreading fast andis being combined with novel trends, such as dig-ital ink (Section 4.4), which are suitable to workon thin clients.

• Local students with a remote professor. Studentsgathered in a computer lab (see Section 4.1) attenda lecture by a remote professor. Not a commonsituation at traditional universities, it is an optimalsolution in most cooperation for development sce-narios. It is also suitable for thin client implemen-tations due to the number of computers requiredand the limited budget and staff available.

• Remote students with a local professor. Studentsusing off-campus computers to access teaching re-sources. This is the new model being adopted by

universities worldwide and not suitable for thinclients (Casella et al., 2007).

• Remote students and professors. Pure e-learningscenario also not suitable for thin clients.

Although the last two situations rule out a thinclient solution given that the academic organizationis not providing computers to access the resources,thin client implementations have been proven to be afeasible solution for use in most “local student” situ-ations.

4.3 Web-based Learning

Web-based solutions are in widespread use for e-learning. These solutions could be part of distancelearning or e-learning generally, but we have pre-ferred to examine them separately due to their widedissemination.

Special-purpose hardware for thin clients or com-mon PCs operate here as thin clients for remote learn-ing, since its limitations do not affect most web ap-plications. Some educational solutions that use web-based services have already proposed the use of thinclient technology in the classroom (Andria et al.,2007). Even web-based scenarios including complexrequirements are good scenarios for the use of thinclients (Callaghan et al., 2007), provide they do notuse multimedia or high-motion services.

4.4 Digital Ink

New technologies are making a claim for a place ineducation in the classroom. Most of these technolo-gies are publicised as new e-learning strategies, butsome, such as digital ink, should be studied sepa-rately. It is not possible to decide whether a sce-nario is suitable for the use of thin client technology,based only on the above strengths and weaknesses. Inthis case, digital ink should be singled out from othere-learning strategies because it proposes the use ofspecial-purpose hardware devices instead of commoncomputers used in conventional e-learning. For exam-ple, a proposal for the use of theClassroom Presen-ter3 application (a software platform for digital ink)recommends the use of tablet PCs by students. TablePCs are really modern devices for which a thin clientis no suitable (Anderson et al., 2007).

4.5 Education in Developing Countries

Health and education are fundamental aspects for acountry’s development. Education, especially in tech-

3http://classroompresenter.cs.washington.edu

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nical fields, is an important goal if developing coun-tries are to emulate the information access opportuni-ties of developed nations (Krikke, 2004). However, aneducational institution in a developing country can-not afford the cost of setting up and maintaining acomputer lab. Cooperation for development guide-lines call for the use of sustainable technologies andsolutions, meaning the purely financial contributionof purchasing a computer lab is not acceptable. Thinclient technology could further the use of computerlabs in developing countries in a sustainable way. Inthis regard the following is an example of a successstory in terms of the technology proposed in this pa-per.

In 2006 the Technology for Development and Co-operation (TEDECO) Group4 led by professors of theSchool of Computing at Universidad Politecnica deMadrid, Spain, launched a new distance educationproject at University of Ngozi (UNG), in Burundi.A committee formed by members of the TEDECOgroup and expert engineers explored several optionsfor setting up two computer labs at UNG. The limitedbudget and the availability of very old computer re-sources were key points to consider when making afinal decision (Martınez-Mateo et al., 2009).

The use of thin client technology in computerlabs proved to be a success, especially taking intoaccount that it was tested in a really tough environ-ment, where there were no qualified staff, apart from atechnical support staff working exclusively on main-tenance. The project was considered a success dueto (Martınez-Mateo et al., 2010): (i) the increase inthe number of subjects that were offered over an e-learning platform like Moodle using the new com-puter labs, (ii) the increase in the number of studentschoosing to study at UNG, and (iii) the offer of a newcourse (fourth year) as result of student demand andthe new subjects offered.

4.6 Unsuitable Scenarios

Although tt is important to ascertain the main scenar-ios where the use of thin client technology is suitable,it is even more necessary to identify scenarios wherethis technology should be avoided. To identify scenar-ios that are unsuitable for the use of client technology,always keep in mind the key weakness highlighted inSection 3: high-motion. A list of scenarios that arenot suitable for thin clients follows:

• Distance learning, unless it requires the physicalpresence of students in a classroom.

4http://tedeco.fi.upm.es

• Multimedia learning, which is a discipline thathas been especially developed in certain sectorsof education, such as medicine (Ruiz et al., 2006).

• Mobile learning. As stated in Section 4.4, e-learning strategies calling for student mobility cannot be implemented with thin clients. These sce-narios require the use of special devices that arenot covered by the current thin client technology.

Although there are unsuitable scenarios related tomultimedia, video, and other high-motion resources,the majority of computer-based scenarios do not re-quire these features. Therefore, thin client technologyis an alternative that is worthwhile considering.

5 CONCLUSIONS

Computer-based learning methodologies and relatedinfrastructures are essential nowadays at any level ofthe academic world. Computer labs and required ICTare becoming an economic and staff resource barrierfor all educational institutions. Thus efforts to providemore effective solutions will have a practical impacton education.

Thin client technologies have proven to be a goodoption for reducing budget and maintenance require-ments in scenarios with more than five to eight com-puters. However, it would be a mistake to defend thissolution without examining what use is going to bemade of the lab equipment. There are many educa-tional scenarios where thin clients are cheaper to use,easier to maintain and easier to upgrade. In this pa-per, we have identified the main advantages and limi-tations of thin clients regarding the most common sce-narios. A widespread of this technology in some caseswould improve global computer literacy.

ACKNOWLEDGEMENTS

We would like to thank the Universidad Politecnica deMadrid’s Office of Cooperation for the Developmentfor its financial an logistic support5, and the mem-bers of TEDECO group for their interest, constructivecomments and active participation in the developmentof this paper.

5This work is partially supported by the project MES-TUN (Monitoring, evaluation and technological sustain-ability of the University of Ngozi) funded by the call 2009of the Direction of Cooperation for the Development of theTechnical University of Madrid.

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