CYBER NOTES January, 2006 by Dave Benore

MYSTERIOUS KEYS OF THE KEYBOARD

When one looks at today’s computer keyboard the standard typewriter keys are easy to recognize. But what about Numlock, PrintScreen(PrntScr), Insert, and some others? What do they do?

When IBM first brought out the PC computer the keyboard had only 83 keys, not today’s 101 or 104. There were no cursor control (arrow) keys, Home, End, Page Up and Down keys, no Insert or Delete key. Instead, these key functions were included in the numeric keypad on the right side of the keyboard. They are still there today. Look at the “4” key. See the left facing arrow? The Numlock key toggled the numeric keypad between entering numbers or controlling the cursor. It still works today.

Today’s computers boot-up with the Numlock key “on”. A light usually is lit by the Numlock label. The keypad then gives you a number when pressed. Push the Numlock key once to turn off the light. Now the keypad moves the cursor around or pages up or down. Or it might delete something (the period key)! Press it again to get numbers back. If you accidentally press the Numlock key without realizing it, strange things will seem to happen. If that happens, check the Numlock light. Press it to turn on the light.

These alternative functions, along with keys like Pause/Break, Scroll Lock, or SysRq are “legacy’ keys—a legacy of earlier Dos operating systems. Several of them still function while others seem to do nothing. However, some programs still use them, particularly games. Scroll Lock still works with many spreadsheets, causing the whole screen to scroll instead of just moving the cursor.

In the old DOS operating system the Print Screen key would send a copy of whatever was on the monitor to the printer. Not so today, using Windows. Press it and nothing seems to happen. But Aha! Unseen by you, an image of the monitor screen has been sent to the Windows Clipboard. If you open any program that handles graphics, such as Paint or Word, and paste from the Clipboard into it, the captured screen image will appear. From there you can print it using the standard print command of the program.

When IBM changed the 83 key keyboard into 101 keys many keys were added, including the four cursor control keys, and the Insert, Delete, Home, etc. keys. When Windows came out, some of these keys were no longer used but were kept because older programs did use them. And they’re still there today!