$199 Linux-ready zero client offers GbE connection
Nov 18, 2014 — by Eric Brown 5,144 viewsViewsonic and Userful announced a $199, 3.5W VDI client that lets up to 20 Linux or Windows sessions run from a single Linux server via gigabit Ethernet.
Userful has been selling its Linux-ready, Virtual Desktop Infrastructure (VDI) thin clients to educational and corporate buyers for years. The company claims to have one million “seats” out in the market. Now Userful and hardware manufacturer Viewsonic have teamed up on a new “SC-U25 Value” VDI Client system based on Userful’s Linux server-based Userful Multiplatform software.

SC-U25 Value VDI Client
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The SC-U25 model that is available for $199 comes with “Chrome-like session” support, and offers a choice of Ubuntu, Red Hat Enterprise Linux, or CentOS Linux guest OSes. The system also supports Android, and Windows sessions are available via separate VDI licensing from Microsoft. There’s also a $420 model that bundles Windows 7 Pro licensing.
Unlike most thin clients, which usually connect to remote servers via the web, the SC-U25 directly shares the processing power of a local Linux server PC running the Userful Multiplatform VDI software. While some earlier Userful solutions have used USB to connect to the server, the SC-U25 uses gigabit Ethernet for more flexible deployment.


SC-U25 rear view (left) and VESA mounted
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Up to 20 Linux-based Chrome Browser sessions — or 10 Windows sessions — can be shared from a single Intel Core i7 based server, says Viewsonic. Running Chrome sessions, the total cost of the Core i7 server along with 20 SC-U25 systems and the required server-side VDI software stack, comes to $359 per station, says the company.

SC-U25 detail view
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The SC-U25 is designed for education settings including libraries, labs, and classrooms, as well as SMBs such as service businesses, medical and dental offices, and call centers, says Viewsonic. Hotel business centers are also noted as a good fit.
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Under the hood
Timothy Griffin, CTO and cofounder of Calgary, Alberta based Userful offered this succinct description of the SC-U25 in an email: “The device is basically an Ethernet connected graphics card and USB hub that together with the Linux server software creates something that will turn the traditional VDI industry on end.”

Userful Multiplatform architecture
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Each SC-U25 VDI client integrates three key chips: an Elite Silicon Ethernet-to-USB bridge, an SMSC UFX6000 USB graphics controller, and a USB audio adapter of unknown origin. The client does not itself run Linux, but rather acts as a remote terminal to the central server, which runs the CentOS-based “Userful Multiplatform” VDI software stack.

SMSC UFX6000 USB graphics controller block diagram
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The SC-U25 offers a gigabit Ethernet port, a VGA port, and four USB 2.0 ports. Audio jacks and an optional USB keyboard/mouse combo are also available. The 120 x 80 x 26mm system weighs 0.16 Kilograms and is available with VESA mounting for attaching it to the back of a display. The system has a 5V DC power supply and runs on just 3.5 Watts, says Viewsonic.
The Linux-based Userful Multiplatform software that runs on the server provides N+1 redundancy. This is said to enable IT administrators to assign deployed SC-U25 clients to corresponding host servers and redundant failover servers.
Specifications listed for the Viewsonic SC-U25 VDI client include:
- Key silicon components:
- Gigabit Ethernet to USB bridge (Elite Silicon)
- USB graphics controller SMSC UFX6000)
- USB audio controller
- Display — VGA port, up to 1920 x 1080
- Networking — gigabit Ethernet port
- Other I/O — 4x USB 2.0 ports; mic-in; headphone out
- Other features — 100 x 100mm VESA mount; optional USB keyboard and mouse
- Power — 5V DC; 2A, 10W; 3.5W typical consumption
- Operating temperature — 0 to 40°C (32 to 104°F)
- Dimensions (with stand) — 120 x 80 x 26mm (4.7 x 3.2 x 1.0 in.)
- Weight — 0.16 k (0.35 lbs)
- Operating system — Userful Multiplatform (installed on central server):
- Linux (Ubuntu 10.04/12.04 or RHEL/Centos 6.x)
- Native Cloud Sessions (with Chrome Browser)
- Supports Android (x86)
- Supports Windows XP/7/8 (requires Microsoft VDA licensing)
- Protocol support — RDP; RemoteFX
“Basically this means a customer is getting a full VDI solution (including endpoint device) for less than the typical cost of a thin client,” says Griffin. “The only thing that isn’t included is any guest OS (e.g. Windows) licenses you might require. Obviously this is the case with all VDI solutions.”
Further information
The ViewSonic SC-U25 Value VDI Client will be available in December at an MSRP of $199. More information may be found at the Viewsonic SC-U25 product page, as well as at the Userful Multiplatform product page. A demo of Userful’s browser-based Userful Control Center management tool is available here.
Why VGA and not DVI or HDMI?