Biblio Tech
Information Technology for Libraries

Java, NCs and NetPcs

Updated: 12 April, 2001


Tech briefings

ILL Update
Z39.50 part 2
Lotus Notes
Java, NCs and NetPcs

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Java, Network Computers and Network PCs


The briefing covers, Introduction, Client-server, Windows terminals, NCs, NetPcs, Costs, Who will win? Some confusions, The Politics, Implications for Libraries, Multi-user NT,

Update April 2000 - Oracle announce a New Internet Computer.



The computer industry is busy re-inventing how client hardware and software should be organised into more manageable units - hence the rise of NCs, NetPCs, and a whole host of innovative software like Java and Winframe.  Library system suppliers also wish to reduce support costs and are adopting these technologies in new systems. The BTR Technology Briefing will guide you to appreciate the basics of the technology and where the benefits lie.

Each component concept of this complex new mix of technologies is briefly described below together with comments on applicability, costs and problems.

Client Server

Client-server is a general term applied to systems where the different software functions have been separated cleanly so that the different components can be more easily managed. Early computer systems have been termed "monolithic" in comparison.  Remember that client-server is not a specific term - it is like saying about your library that we have adopted "team-working" without saying what the teams do or how they interact.  The terms "client" and "server" have been re-defined over the last ten years and in some cases mean the opposite of their original definitions!

Simple 2-tier client-server

The usual meaning of client-server is the separation of the application programs from the database.  The application program (the client) asks for data from the database management system (the server), changes it and sends it back to the database.  The two programs communicate via a standard protocol e.g. SQL (see Technology Briefing on Databases).  The client application and server can be running on separate computers or on the same computer. Their logical separation makes management and programming easier and more flexible. A widely adopted model for client-server has been to have application programs running on a PC - using MS Windows graphical interface and the DBMS running on a separate central server - e.g. Ameritech's Horizon. Generally, the application client is what is known as a "fat" client - because it is a large complex program.

Problems with 2-tier client-server are:

  • Pcs as clients are costly to administer and upgrade
  • PCs are often over specified and costly for simple jobs e.g. circulation desk - yet one is needed for each user.

The separation of the client application from the server usually requires a considerable re-working of the software and suppliers have usually taken the opportunity to rewrite the application from scratch.  Most modern systems use client-server architecture.

3-tier client-server

Separates out the user interface from the application program to form a third "thin" client as shown. This creates a "thin client/fat client/server" setup.  The thin user-interface client can run on a simple machine that features low purchase and management costs - for example the  "Network Computer" (NC) as defined by Oracle Corp. The advantages of this operational model are:

  • Simplicity at the user end - PCs can be simpler
  • Flexibility - a wider range of terminals are possible
  • Security - user terminals contain no user configuration capabilities
  • Ease of management - user terminals and application software are controlled centrally.

All of these features should drive down costs.

Whereas the creation of a 2-tier client-server system required re-development, the deployment of a 3-tier Pictureclient-server model is more easily done. If the application client is a PC, and the application can be run on an NT server. Then special multi-user interfacing software e.g. Winframe from Citrix, can drive several simple thin clients - each one running the same application. 


Java is a computer language and other operating utilities. The Java language is similar to C++  which is commonly used to write Windows style applications. The Java products have been designed with several unique features that will effect the way client-server applications and "thin-clients" evolve.  The key features are:

  • Programs written in Java can run on any type of computer without rewriting - this saves development effort and means for instance that "thin" client hardware can be changed as required without changing programs.
  • Java is designed for networks - programs can be loaded as required from a central server.

Some key benefits flow from these and other features:

  • Simple computers can run with software downloaded as required from the network - reducing management costs and increasing security.
  • The "simple computers" need not be PCs running Windows - this breaks the monopoly of Microsoft and Intel for desktop computer power.
  • The "simple computers" can run Windows applications if desired see Winframe below.

Watch out for the Microsoft response to Java - Dynamic HTML.

The Network Computer (NC)

The Network Computer ™ (NC) is a concept defined by Oracle.  It has other names Web PC, Java terminal etc. The JavaStation from Sun is the same concept.  Essentially it is a low cost computer designed to run Java applications loaded from the network to which it is attached.  One or two applications are permanently loaded - a Web browser and mail reader typically.  It has no discs and does not run Windows applications directly. All management takes place via the network.  It is thus cheap to buy and cheap to run.

Together with Winframe, Ntrigue and similar software, an NC can run virtually any programs including Windows applications and fits perfectly into the 3-tier client-server model as a low cost "thin client" and can also run "fat" clients if required.

Windows Terminals (WTs)

A Windows terminal is a device that appears to be running Windows but is really just a terminal to another computer running a multi-user version of Windows NT. The Windows terminal is the ultimate "thin" client since it uses virtually no computing power. A WT can run any Windows application that can run under Windows NT. All the management and security issues are handled centrally on the NT server - thus lowering costs considerably. Although the central server needs to be quite powerful to support many Windows terminals, the low cost of the Windows terminals compared to a PC compensates. It is now a well-established method of controlling users - especially in colleges and universities.

A Windows Terminal is similar in physical terms to an NC - it is a low cost device without disc storage but it is not designed to run Java. Typical is the Winterm range from Wyse.

Multi-user NT

The trick that makes the Windows Terminal concept work is software from Citrix called Winframe.  Software resides on the NT server and links to client software on the Windows Terminal.  Only the mouse clicks and screen data goes to the Windows Terminal and so the concept works well over low bandwidth (slow) networks and with old and slow PCs.

Multi-user NT as exemplified by Winframe and Ntrigue from Insignia, can also be accessed by Java based NCs so that an NC can appear to run standard Windows applications and any library application designed to run on Windows NT. So any library system supplier can now offer NC support and a method to interface those old PCs that won't work with the latest software.

Ntrigue can even run Windows applications over the Web. You can try it out by accessing their Web site  Once you have the software downloaded, your Web browser turns into a Windows terminal. Try it on a Mac or an old PC - see the Review

Network PCs (NetPCs)

The aims are similar to those of the NC - lower management costs and simpler overall operation - but does not have the same reliance on Java. The NetPC however retains Windows capability locally and can operate independently of the network - unlike the NC. The NetPC can be seen as a stripped down PC with more security by having no floppy disc and with built in interfaces (Desktop Management Interface or DMI) to central management software. The idea is that you switch on your NetPC and the pre-set applications start up, and you have very limited capabilities to change setups.

Much of the manageability of the NetPC will come from the Windows NT server to which the NetPC is connected.  This functionality will mostly come with Windows NT version 5 - due in 1998.

The NetPC can run Java programs and operate like an NC but it will never be quite as simple.

The Politics

In reading the above descriptions and future press reports about the various varieties of new desktop computer systems, you need to be aware of the commercial rivalries that exist and colour the claims presented. NCs are being promoted by Oracle, IBM and SUN. Microsoft and Intel are promoting the NetPC concept in response to the Network Computer concept that is a threat to the dominance of the desktop currently held by these two companies. The NetPC has a specification to which hardware companies are responding to bring out machines during the latter part of 1997.

Some Confusions

It is very easy to be confused when discussing these technologies and no doubt deliberate confusing statements will be made by the rival camps.  One particular confusion is that a PC or NetPC can run Java programs just like an NC - so why bother with NCs?  Similarly, NCs, NetPCs and PCs can all act as Windows terminals.  The point is that the simpler device is cheaper to acquire and manage yet does most of what the PC can do.

NetPCs and NCs can have various levels of hardware sophistication which will further blur any polarised definitions used by companies plugging their own solutions. 

In the end it is best to hang on to the main differentiation - NCs run Java, need the network and are not limited to one operating system or hardware chip.  You should also remember that the aim of these devices is reduction of costs by providing a simpler, network-centric and therefore easier to manage computer. Arguments that complain about the limited capabilities of NCs miss the point - they are meant to be limited.

Who will win?

The computer industry is over inclined to think in terms of binary choices - perhaps because of its particular mathematical foundations.  Technologies seldom totally eclipse each other in the manner of VHS and Betamax. After all, there are hundreds of applications running under Pick database structures (as Unidata and Universe) long after the relational model was supposed to have "won".

I have no doubt that the NC concept will flourish and grow where it is appropriate (see below) and that simpler PCs will move to a central management organisational model.  Power users of PCs will also survive with highly idiosyncratic setups suited to their own uses. 

Implications for library systems

Management of PC has been a problem for librarians since they were first deployed to library staff and users. Compared to the dumb terminal the additional functionality has been an expensive benefit - and in many cases, a totally under used one. The Pentium PC on an issue desk is probably not performing to its full capabilities!

The NC gives the librarians and the system designer the opportunity for system simplification and lower cost. In general they are most appropriate where there is:

  • Limited range of programs to be run
  • Multi-use of workstations by staff
  • Remote users - e.g. a branch situation
  • Remote data - e.g. access to a large central database not local PC type files.
  • Paramount security issues
  • Dumb terminal access

Many of these characteristics apply in libraries - a circulation desk terminal for instance runs a limited number of programs that access remote centralised data often from a remote branch. OPAC terminals require security from "fiddling" and many library systems still require access to legacy systems with dumb terminal emulation - so NCs fit these tasks very well.

Cataloguers and acquisitions staff on the other hand may need more local data e.g. Dewey on CD-ROM, Z39.50 clients, secure local spreadsheets etc. and may be better off with Standard PCs or NetPcs.

Librarians should try to match the needs of their computer users - many and varied as they are - with the appropriate technology - or at least be aware of technologies that may be otherwise forced upon them - and remember that old PCs may be able to be re-used as Windows Terminals.

Suppliers face an interesting time as ever.  By taking a "Java Centric" route that allows NCs to be used widely, they can reduce the support and update distribution costs for their products.  But they do not want to be faced with re-developing in Java.  Already Java programming tools are making re-development less of an issue - for example C++ programs can now be compiled to a "Java Virtual Machine" and thus run on an NC.  But there are plenty of other considerations that will be particular to each system and supplier's legacy. Suppliers have already declared that they will be developing various Java components - the new INNOPAC project Millenium will have Java through all modules .  BLCMP have released Talis JV a Java applet - a thin client - that can be downloaded to any PC browser to run the system.

The Costs

NCs and NetPCs are claimed to bring in about 30% savings in management costs - NCs being generally potentially the more efficient.  NCs will probably be cheaper to acquire than the lowest cost NetPC.  If the NC concept take off as a consumer product then the costs will go down rapidly.

For detailed costs of Winframe and other NC enabling software, visit the Getech web site. Getech are hardware and software distributors to educational institutions.

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