geekyThe IBM 3270 series of terminals and terminal controllers was designed to work much differently from the average computer terminal. Instead of sending characters one at a time when a key is pressed, and displaying them one at a time as received from the host, it was designed to present a form to the user, which he fills in and transmits to the host in one big glob. This was done to minimize the demands on the host computer, thus making things more efficient.
In later days, IBM realized that it might be a Good Thing if its terminals could be used with host computers from other manufacturers. They added the ability to do that, although it was a bit clunky. Even later, they added networking abilities to the controllers.
I have a 3174-61R controller with a Token Ring interface. (That was $500, complete. If I'd gotten one with an Ethernet interface instead, it would have been $3500.) I've also got a nice 3472 infoWindow terminal to go with it, as well as a couple of 3270 terminal cards for my former employer's product. I've also got a Token Ring adapter in one of my Linux systems.
I had to rebuild the kernel in Red Hat Enterprise Linux version 3 because they didn't include the TMS380 Token Ring adapter module as standard. I also had to tell that system to forward the packets and do address masquerading, so the 3174 appeared as though it was on my main LAN. With that done, I was able to log into the main Linux server here:
and run the mutt email client:
and the slrn Usenet news reader:
Needless to say, these look very strange to an old-time mainframe geek like me. That's why I had to do it.
