I've found an interesting product called ThinAnywhere from Mercury International Technology (MIT) (see the first URL at the end of this article). Anyone who uses Windows 2000 Server Terminal Services or Citrix MetaFrame for UNIX—most of the people reading this, I imagine—should take a look at this product. I haven't formally reviewed the product, but based on my discussions with the company and the demo I saw, it's worth examining.
ThinAnywhere is middleware that runs on a UNIX or Linux box. MIT originally developed the product because the company needed low-bandwidth connectivity to UNIX and Linux servers for its engineering applications and found that existing tools didn't work for its OpenGL applications. People who connect to a ThinAnywhere server can run any application located on the server (e.g., an RDP client). The software includes a tool called Remote Device Control that permits local access to plotters and tape drives. The number of people who can usefully connect to one server depends on which applications they run; obviously, text applications use far fewer resources than engineering applications. MIT recommends 15MB to 30MB of memory per concurrent connection for ThinAnywhere servers. This setup should sound familiar to anyone who reads this newsletter; it sounds like a terminal server, but (for Windows clients) one that could allow access to another terminal server. Why should you care about a product that adds an intermediate layer to Terminal Services?
For Windows users, the reason is simple: licensing. If you use the RDP client located on a ThinAnywhere server to access a Windows terminal server, the only computer that uses a Terminal Server Client Access License (TSCAL) is the ThinAnywhere server. (Incidentally, although I'm told that some Linux builds draw their TSCALs from the unlimited pool on the Terminal Services license server the way a Win2K Professional machine does, the ThinAnywhere server uses a typical TSCAL.) To access the ThinAnywhere server, you have to pay for licenses. But MIT licenses access to the server on a per-concurrent-connection basis, not a per-seat basis, and the licenses cost a little less than TSCALs—about $100 each. The upshot is that you could theoretically use a ThinAnywhere server to effectively license Terminal Services on a per-connection basis—but at the cost of adding an intermediate server.
People who want to access UNIX applications over slow links might also be interested in this product. The X protocol demands a lot of bandwidth—one reason that MetaFrame for UNIX is such a good idea. MIT tweaked the protocol to make it use significantly less bandwidth so it will work over slow links, just as Graphon did with its UNIX product (see ASP News and Views below).
When it comes to providing access to a Windows terminal server,ThinAnywhere is a bit of a kludge. For example, because the product runs only on UNIX and Linux, not Windows, you have to run it on Linux and use a Linux-compatible RDP client to access a Windows terminal server. I ran the demo using the rDesktop open-source Linux RDP client (available for download—see the second URL at the end of this article). Although this client works, it's slower than the Windows RDP client. But MIT's John Gaberino thinks that the company has identified the reason that the client is a little slow and can resolve the problem. MIT plans to develop its own RDP client and include it with the package. Adding one more server to the connection chain increases the possibility of connection failure. However, ThinAnywhere is an interesting solution to the problem of getting concurrent-user licensing for a Windows terminal server. Users who need to access UNIX application servers over slow links might also want to take a look.
http://www.thinanywhere.com
http://www.rdesktop.org
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Arthur Chan July 27, 2001