Quick demonstration of the functionality of the 3178 terminal

WROTE A FORMATTED SCREEN WITH FIELDS

I set up a sample screen, simple but exhibiting a number of important features, which appears when I start up the terminal. This divides the screen into twenty fields, some unprotected to allow operator data entry and the others supporting labels and light pen select fields.

The top two lines are for entry of the Name and ID. The ID field must be numeric. The third through fifth lines are available for entering Notes. The first field of a line is the protected and intensified text label, followed by the unprotected field for the operator to key in a value. 

Immediately after that value field, there is a numeric & protected blank field which signals that the terminal should, when the last character of an input field is entered, autoskip to the next unprotected (input) field. If I did not use the numeric & protected field, it would have simply advanced to the next sequential field which is protected and won't allow input. 

There are three selection lines for the light pen - using a ? character to define it as selection. While I don't have a light pen, if the cursor is positioned in the field and the CURS SEL key is pressed, it acts as if the light pen were used. Each time I select the field, it toggles the field between ? and >, with the later character indicating it was selected. 

Below those three lines I have two action type light pen fields. Using the CURS SEL in either of them will send an event to the mainframe indicating that the operator has requested an action. They differ in how they present to the mainframe, but otherwise are similar.

My final input field is on line 24 of the display and it wraps around to the first few character positions of line 1; this was chosen to stress the logic needed to handle wrap-around buffer addresses. 

At the end of the work with the formatted screen, I hit the CLEAR key which wiped away all the fields and characters on the screen. It became a single 1920 character unformatted expanse that I can type into in any location. 

SHOWING OFF THE FUNCTIONALITY

This video IBM 3178 Operation and Use on YouTube shows me taking the terminal through its paces, moving around, entering data, watching it ensure protection and proper formats, and many other operations.