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ADMINISTERING THINSYSTEM

Most administrators are password-happy. So, the first thing the ThinSystem software does is put up the change administrator password screen (see Photo 2).

After a password is established, choosing the Admin Mode entry from the user menu exposes the system admin functions. After entering Admin Mode, the administrator can alter the administrative password, select the position of the WinLight taskbar, configure TCP/IP, define connections, and perform file transfer functions.

The taskbar display settings let you put the taskbar at the top or bottom of the WinLight screen. A mouse-over mode can also be set here. Ctrl+Esc activates the taskbar if no mouse is present.

ThinSystem can communicate with a remote server via the SBC-MediaGX Ethernet interface or standard RS-232 via a modem. Unfortunately, the SBC-MediaGX development kit didn’t come with an external modem. If your design is dial-up based, be sure to take that into account.

Either way, Datalight Sockets must be configured for everything to work correctly. If the connection is to be made via an NIC and DHCP is not available, the system administrator or designer must supply the correct IP address, net mask, and gateway address. Photo 3 is where the IP work begins.

I don’t have a direct LAN connection to the Internet so I dug out an old U.S. Robotics 28.8 Sportster external modem and attached it to COM2.

Since the Florida Room is without a Citrix server, the Datalight folks were kind enough to allow me to access theirs. All I had to do was enter the COM port, phone number of my ISP, my ISP login name, and my ISP login password. The PPP skeleton can be seen in Photo 4.

 

The next step was to set up a connection to the Citrix server out in Washington State. All the data I needed was supplied by the Datalight folks, with the exception of the connection name. Photo 5 shows the Connections Properties window.

 

OK. All set up and ready to connect to the Citrix server. I pushed the mouse pointer to the top of the screen, and the Start button appeared.

A click of the Start button, another click on the Connections menu item, and a final click on the Circuit Cellar to Datalight connection. Nothing, nothing at all. The phone line won’t give me a dial tone and the client just keeps retrying with no luck.

I went to the nearest phone that was on the same line I was attempting to dial from and picked up the handset. Silence. Dang hurricanes! I’ll bet the little splice job I did on the phone line outside the Florida Room is a tad wet from Floyd.

Well, not just wet—gone. I never claimed to be a professional "telephone guy." No problem. I fixed it and fired up the ThinSystem client again. Still nothing.

Two days later, I discovered that putting text into the Modem Init string field (Photo 4) under PPP Configuration was a mistake. (I do claim to be a telecommunications expert.)

Seems that just entering "AT&F" to reset the U.S. Robotics external modem didn’t hack it with the ThinSystem software. The giveaway was that after the command was processed, it was echoed back to the terminal debug screen and the expected "OK" never appeared.

The key to entering text in the Modem Init field is to add everything as a character. That is, to send a carriage return, you must enter its Hayes command equivalent.

The simple thing to do was to not put anything there. Son of a gun! After applying that fix, I got a dial tone and connection but still no logical session with the Citrix server. To the phones….

I spoke with Datalight’s Robert Krantz and his first suggestion was to hook up to the ISP and attempt to ping 12.17.135.100 (the Citrix server). Sounds reasonable. Did I say something about being a telecommunications expert? It helps to enter the correct IP address.

Again I fired up the SBC-MediaGX/U.S. Robotics combo. The normal modem tones were exchanged, my ISP delivered an IP address to my SBC-MediaGX, and whap! A little man in a business suit holding a briefcase was flying on my MetaFrame screen that was being served from the Citrix server. Moments later, a familiar sight, the Windows NT desktop, appeared.

MY DESK(TOP) IN WASHINGTON STATE

Just for grins, I clicked up Microsoft Word to look at what NIC was installed on the server. I played around just like I’d never seen NT or any of its innards. It was pure joy. The reality of operating a Windows NT machine from an embedded PC all the way across the U.S. was awesome.

Although the SBC-MediaGX has plenty of spunk, I wasn’t even moving its stress meter. And then it occurred to me that I was only connected at 26 kbps, not 56 kbps, through an ISP connection running heavy Microsoft apps as if I was sitting there with Mr. Krantz!

Once again, the computing world has gone full circle with thin client technology. And now, Datalight and Robert Krantz have proven that it doesn’t have to be complicated (or big) to be embedded.

Fred Eady has over 20 years’ experience as a systems engineer. He has worked with computers and communication systems large and small, simple and complex. His forte is embedded-systems design and communications. Fred may be reached at fred@edtp.com.