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Connecting Your Mac To An IBM Mainframe

So you can connect your Mac to a UNIX host on the ECN, but that's no help, that's just not enough...you want to connect to an IBM machine!...well excuuuse meeee! tn3270 is just the package you are looking for. It is available on the "ECN Public" file server. Within the folder marked "tn3270" (surprise!), you will find the application. It is in a file called "config.tel" with several examples (depending on your kind of Mac) and the Reference Manual. I will go through a couple of very easy steps to get you started. As an example we will connect to the PUCC's IBM 3090, vm.cc.purdue.edu. Most of the following you can find in the tn3270 Reference Guide.

tn3270 allows a Macintosh to emulate an IBM 3270 terminal, this includes extended highlighting, APL, and 3179-compatible graphics. The different Macintosh screen sizes and color are supported. If IBM VM/CMS is being used on the host computer, tn3270 will support file transfer (an FTP server). You are required to have a Macintosh 512K, 512Ke, Plus, SE, SE/30, II, IIx, or IIcx hooked to the ECN Mac network to use this package. It requires 153k of space.

First, you need to get the package off the "ECN Public" file server. The folder tn3270 contains everything you need, just drag the folder over to your hard disk or floppy(405K), see the figure below. I recommend printing the Reference Manual at your nearest Postscript (Apple) printer; it contains the much needed keyboard mappings between a 3270 terminal and a Macintosh keyboard.

                       Figure 1 shown here

tn3270 requires that it be configured before using. There are three configuration files:

• settings: The settings files contain user preferences, such as cursor shape, highlighting options, and screen format. This is a tn3270 document with the same icon as the application. Double clicking a settings file (yours) will start up tn3270 with your settings and will initiate the connection to a machine. If tn3270 is started without a settings file, it will display a dialog box allowing the user to select a settings file (if one exists). If nothing is selected then default settings are used (which you may or may not want). Several settings files are included on the "ECN Public" file server. There is one for a Mac Plus, a Color Mac II, and a B&W Mac II. For the purposes of this article we are going to use one of these settings file to make our own settings file.
• netconfig.tel: This is required for tn3270 to receive an IP address and become a node on the ethernet. You don't need to worry about this because a Kinetics Box (hardware that connects your Mac to the ethernet) does this for you.
• config.tel: This tells tn3270 how your network (ECN) is configured, where machines are, etc. You don't have to worry about this because it has already been made for you (see the first figure). I should note that if you use NCSA Telnet, you might remember that it also requires the file "config.tel" for the same reason tn3270 does. These are the *same* config.tel files. If you already have one for NCSA telnet you don't need to have the one for tn3270.

Now, after reading the above, you may realize that even though tn3270 requires configuration, you as a user really don't need to do a whole lot. To start tn3270 let's "double-click" (assuming we are using a Mac Plus) on the already made settings file for the Mac Plus. This will start up tn3270 with the settings for a Mac Plus.

                      Figure #2 shown here

It will take a short while to do its initialization magic. After it's finished initializing pull down the "Settings" menu and select "Host Name...".

                      figure #3 shown here

You then type the name of the host you want to connect to and click OK.

                      figure #4 shown here

Now to make the connection, pull down the "File" menu and select "Open Connection".

                      figure #5 shown here

If the network is up and running, a connection will be made.

                      figure #6 shown here

You're done! To quit, pull down the "File" menu and select "Quit". You will be asked if breaking the connection is what you want to do, if it is then you will be asked if you want to save the settings.

                      figure #7 shown here

Click "YES". You will then be asked to name the new settings file. I think it's a good idea to name the settings file after the machine you connected to...

                      figure #8 shown here

The result will be a new settings file named after the machine you typed in for the hostname (if that is how you named it). The icon is the same as the tn3270 icon only it is now the name of the machine you want to connect to.

                      figure #9 shown here

Now, to connect to vm.cc.purdue.edu, you simply "Double-Click" on the the icon named after it, and you will automatically make a connection to that machine with the saved Mac settings. No problemo...

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