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White Paper #0002
Ultra Thin-Client Technology.
Advantages of an Operating System-
Less Thin-Client
Last Update: 07/11/2005
The majority of thin-clients available today are based on PC technology, ie they contain an operating system, application layer (RDP, ICA, emulation...), Bios, flash disk and registry...
Axel’s innovative "Ultra Thin-Client" technology brings a unique simplicity and robustness to thin-client computing.

Optimised Hardware

The first diagram shows the complex construction of an operating system based terminal, the second diagram shows that of Axel’s "Ultra Thin-Client" technology:

Operating System

Operating System based
Ultra-thin client

An operating system comprises of several main layers as shown in the table below. Each of these main levels can have numerous sub-levels:
   - Hardware Level - HAL (hardware Abstraction Layer) and Bios
   - Operating System Level - HAL + Operating system + Libraries
   - Application Level

With a PC these numerous levels are essential for application portability, ie supporting spreadsheets, databases, word processing, communications software (firewalls), device drivers etc. However each layer has a significant negative impact on the overall performance of the system.

Unlike a PC, a thin-client will only ever be called upon to run one of several connection protocols (ICA, RDP, telnet), so the multi-layer architecture impacts performance and brings no benefit for portability.

With Axel’s approach there are no intermediary levels between the hardware and the connection protocols so we are able to apply all the hardware resources to the connection protocol.

Optimised Memory Management

The performance of an operating system based thin-client is a factor not only of CPU power but also of the memory available (ie by adding memory to PC its performance is normally improved).

For operating system based thin-clients the minimum memory requirement is dependant on the operating system (XPE requires more than Windows CE). With Axel’s ultra-thin client (and the absence of an operating system) all the device’s memory is available for the protocols and emulations (TCP/IP, RDP, ICA...). The question of how much memory is required is not applicable. For example to obtain the optimal RDP performance 3 or 4 Mb are sufficient. This memory is mainly used for caching. Making more memory available will not improve the performance. This is why Axel does not need to offer a range of different models with different memory sizes.

A Terminal offering 100% immunity against Viruses

Security has become a critical consideration for today’s information systems, and a significant driver for adopting a thin-client strategy. A terminal with an embedded operating system is susceptible to PC viruses. For example, XPE, a common thin-client operating system, is exactly the same operating system XP that runs on PCs, so is susceptible to the same viruses.

As such XP based thin-clients are subject to the same security considerations as a PC, ie, regular hotfix updates and installation of up-to-date anti-virus software.

There are no such concerns with an Ultra-Thin client.

Complete Control of the Product

Axel has total control over all aspects of design, manufacture and production of our products.

The circuit boards (hardware) are designed by our engineers, as is all the software (firmware). The TCP/IP stack , the emulations (ANSI, VT, 5250 3270...), the graphical protocols (RDP, ICA and VNC), connection protocols (telnet, SSH...) and USB stack are all developed in-house by our own R&D team.

Consequently Axel has the total control of the whole of the terminal .(Hardware and firmware, no part is sub-contracted).

This requires Axel to have in-house an incomparable knowledge of the protocols and emulations and how they interact with each other and the hardware. It also means that we are qualified to address technical questions at a source code level.


Having no operating system also provides the following benefits:

  • Immediate availability: the Axel terminal "boots" in a few seconds
  • Simplified set-up: the terminal configuration is based on simple concepts which allow very fast commissioning. This same set-up can be reached remotely via telnet.
  • Supportability: being wholly developed in-house, the protocols and emulations do not depend on any third party companies.


All operating system based terminals are fundamentally the same (in the way that all PCs are fundamentally the same). As all use the same ‘building blocks’ it is impossible to differentiate one from another in terms of technology. As the manufacturers ‘buy in’ the building blocks they have no control over the product.

By contrast Axel’s “Ultra Thin-Client" technology is wholly owned and developed by Axel. This is a significant asset and truly sets Axel aside and ahead of the pack in terms of freedom to develop new features and enhance existing protocols.