Ah, the calming green glow of an IBM 3270 terminal, a sight that most of us only get to enjoy through a software terminal emulator today. In their time, mainframe-connected thin terminals were the most efficient way to deliver applications and make use of limited processing power. With the development of the microprocessor and the introduction of the Personal Computer in the 80’s, users had sole access to processing power that was only available in “super computers” from ten years earlier.
Today, processing power and connectivity are pervasive; however, organizations still grapple with complex IT problems. Among them, mitigating the higher administration costs associated with a sprawling workforce and deploying the distributed applications to support them. Also of concern are data security and spiraling software and hardware licensing costs. A look back at the decade’s old thin-terminal/mainframe model can provide some answers.
> Return of the Thin Clients
Businesses are realizing that a full-featured desktop PC is not the solution to every desktop usage scenario. Often the tending and feeding of these systems, not to mention the acquisition cost of the hardware and OS software, does not justify the expense. Using a thin client/terminal server model, organizations can centralize application administration, reduce licensing costs and enhance data security.
Thin clients, by definition, are free of the management and administration that a fat client PC requires. The “thin” is a small boot image that provides networking and any client software required—perhaps a Web browser or a remote desktop client, such as Microsoft RDP, Citrix ICA or NoMachine NX. Thin clients are common in manufacturing terminals, retail point-of-sale devices and kiosks.
Thin client hardware can include repurposed PCs and laptops. A number of hardware vendors offer small-footprint, “thin” devices as well, such as HP, Wyse and Neoware. Thin client hardware is also typically less expensive than its full-fledged PC cousins. The devices generally have fewer moving parts and are more fault tolerant, allowing for lengthened hardware refresh cycles, even five years and beyond.
Microsoft and other vendors including Citrix, Ericom, Softricity and NoMachine, offer a number of terminal services solutions. Open source solutions like the Linux Terminal Server Project (LTSP) and VNC are available as well. Coupled with thin clients, terminal services can help your business centralize software and system administration, decrease client administration, increase platform flexibility (read as replace clunky Windows desktops with SUSE Linux Enterprise Desktop) and minimize licensing costs. Because typically no user data is stored on a thin client device, data loss and theft is also reduced.
Terminal server solutions allow full desktops or applications to be delivered and run from a server. The delivered desktops or applications look like they’re being run from the thin client device or viewer; however the processing is taking place at the server.
> Linux as a Thin Client
Open standards and open source equals flexibility. Already ported to iPods and Playstations, Linux is a natural fit for thin client computing. The kernel and the many utilities and programs that make up a Linux distribution are modular from the start. Meaning, one can mix and match components to achieve the desired functionality, while tailoring the OS to meet the target thin client hardware.
SUSE Linux Enterprise Desktop includes a number of software thin clients standard in the distribution. These include rdesktop (a linux RDP client), vncviewer (a client to access any vnc server), Citrix ICA and Ericom Powerterm (proprietary software thin clients). The NoMachine NX client is external to SUSE Linux Enterprise Desktop 10 and can be found at nomachine.com/download-client-linux.php.
SUSE Linux Thin Client Solutions
The Novell product portfolio includes solutions to create custom thin client OS images based on SUSE Linux.
Novell Linux Point of Service , a solution primarily targeted at the retail sector, is also a great fit for generic thin clients. It includes the tools to create images from a standard set of templates and a management framework to deploy images to geographically disperse locations. Novell Linux Point of Service 9, the most recent release, is based on the SUSE Linux Enterprise Server 9 and Novell Linux Desktop 9 code base. (Look for a new name in the next release based on SUSE Linux Enterprise Server and SUSE Linux Enterprise Desktop 10. SUSE Linux Enterprise Point of Service, is due out the second half of 2007. For more detailed information, visit novell.com/products/linuxpointofservice.)
Kiwi, a more broadly focused technology, can be used to create custom OS images from either the openSUSE or SUSE Linux Enterprise distributions. Kiwi also has the ability to create virtualized images that can run in a XEN hypervisor. To find out more about Kiwi, including how to create custom OS images and liveCDs, see: en.opensuse.org/Build_Service/KIWI.
> Thin Client Solutions
The Linux Terminal Server Project (LTSP) is a great solution for wired computer labs. LTSP is a software add on that can be installed on virtually any Linux server. Thin clients connect to the server when booting and can display a text terminal or a full Linux desktop delivered from the server. For the thin client user, the experience is almost indistinguishable from that of a dedicated desktop PC. LTSP has had particular success in schools where older PCs and thin client devices can be used to deliver a better quality desktop experience to more students than costly new PCs. LTSP also has an attractive open source price point—zero dollars!
End users have access to any software that is installed on the Linux server, which can be a Linux desktop distribution such as SUSE Linux Enterprise Desktop. For a step-by-step guide on how to install LTSP on SUSE Linux Enterprise Desktop 10, see novell.com/coolsolutions/feature/17942.html.
For more information on the LTSP project, check out ltsp.org.
NX is a terminal server technology that delivers a rich Linux Desktop experience even over low-bandwidth, high-latency data links. Developed by NoMachine (nomachine.com), NX is available in a number of small business- and enterprise-focused products that can be used to deliver remote desktop and application sessions. Thin client OS images can bundle the NX client, offering a flexible solution for wired LANs and wireless or modem links.
Windows Terminal Server
Although not always paired with a hardware thin client, Windows Terminal Server delivers a full Windows Desktop session through an RDP (Remote Desktop Protocol) client. Microsoft offers RDP clients for Windows and Mac. A Linux client is also available called rdesktop.
You don’t need a Windows Desktop to connect to Windows Terminal Services. The connecting client OS can be Linux, Mac, Windows or any other platform that has an RDP client. Note: Licensing is the same across all client platforms including Linux. All Windows desktop platforms, including XP and Vista, require a Terminal Services Client Access License to connect to Windows Terminal Services in Windows Server 2003 and beyond.
For the Linux desktop user out there who also maintains a Windows XP Professional machine, rdesktop can be used to remotely deliver your Windows Desktop on Linux (for those rare occasions when you want it). See Getting in Touch with Your Geek in the Q4 2006 issue of Novell Connection for details on setup (novell.com/connectionmagazine/2006/q4/fine_print.html). (See Figure 1.)
Citrix Presentation Server
Citrix Presentation Server, among other features, allows individual applications to be remotely delivered to desktops, again including Windows, Mac and Linux. Presentation Server is installed on a Windows Terminal Server machine and provides an enhanced feature set including application publishing and desktop connections over HTTPS.
Citrix also offers an ideal way to deliver Windows applications to Linux desktops. Only the Citrix ICA client needs to be installed. Published applications can then be run by the click of an icon on the Linux desktop as if they were native, local applications.
Ericom WebConnect RemoteView
Ericom WebConnect RemoteView offers a similar feature set to Citrix, including application publishing and seamless windows (remote applications that look and behave like local applications including window borders and widgets). WebConnect RemoteView also resides on a Windows Terminal Server and, like Citrix, offers an attractive solution to deliver Windows applications to Linux desktops. The Ericom PowerTerm client is installed in SUSE Linux Enterprise Desktop 10 by default, and offers a familiar icon-double-click experience to launch remote applications on a local desktop. (See Figure 2.)
Gartner estimates that companies can save 10 to 40 percent on computer-management costs when switching from desktops to thin clients. (Gartner, When Thin Clients Can Narrow Your TCO.)
> Putting It All Together
Terminal service solutions, even when not paired with thin clients, are still compelling to organizations. The money you can save through centralizing application administration and improving worker productivity (by offering highly available, on-demand applications) is often enough to justify the expense. Adding thin clients to the equation gives you the opportunity to save even more on hardware acquisition, maintenance and client OS licensing costs.
In those scenarios where a full-featured desktop or laptop PC is warranted, offering terminal service solutions provides the added opportunity to reduce licensing costs by using Linux desktops. (Again read as SUSE Linux Enterprise Desktop.) Application publishing solutions from Ericom and Citrix allow Windows applications to be seamlessly delivered to a Linux desktop effectively removing the requirement of running a Windows OS to run Windows Applications.
Where do thin clients make the most sense? Easy targets are fixedfunction PCs that run one or a few applications, connected student labs, manufacturing floor terminals, point-of-sale terminals, multi-user workstations and others.
For what applications are terminal services most appropriate? Bandwidth-intensive applications (often those that make many database queries) are good candidates. By co-locating the terminal server and the database server, application performance can be greatly increased (versus running the application locally where link speed cannot be guaranteed).
Applications that have high availability requirements are good targets, as well. A terminal server farm can be used and session state can be saved between logins. Also applications that are not compatible on a target client operating system can be delivered from a terminal server as though they were running locally.
Using solutions such as NLPOS and Kiwi, you can create a tailored Linux OS image for the thin client application. Images can be as simple as bash text terminal or as complex as a full GNOME or KDE desktop. These images can be delivered by network boot, LiveCD or USB key. Images can run from RAM or be disk-based. These tools provide the flexibility to create the thin client solution fit for a given problem.
Thin clients combined with terminal services, while a nod to computing of days past, offer great opportunities to increase worker productivity, enhance data security and decrease IT administration costs. Leveraging Linux and open source technologies such as NLPOS, Kiwi and SUSE Linux Enterprise Desktop, you can realize increased savings in hardware acquisition costs and client operating system licensing. So size up your fat desktop environment, size down to thin clients and enjoy the calming green glow of money saved.