Use [SHIFT] To Disable Numlock During Data Entry

Original IBM PC (and Ctrl+Alt+Del) inventor Dave Bradley shares what he thinks is the most obscure key combo he ever came up with. And it's still handy today.

InformationWeek Staff, Contributor

August 12, 2011

2 Min Read

This trick goes all the way back to the original IBM Personal Computer--I should know. I was on the team that invented it.

Most of the key combos I came up with to extend the character set of the IBM keyboard are now well-known. But here's one that I bet you've never heard of.

It's a simple keystroke trick. Basically, it lets you use [SHIFT] to temporarily turn Num Lock off, which is handy if you want to use the [UP][DOWN] keys and also type numbers. This way you never have to take your hands off the keyboard. It's most useful in a spreadsheet, but it works in other applications, too.

Try it.

If Num Lock is set to ON--that's the default--holding [SHIFT] down temporarily turns it off. Again, this allows you to use the embedded cursor controls in the keypad.

So, to enter a column of data, with Num Lock ON, type in a number on the keypad. Hold [SHIFT] and strike the [DOWN ARROW] key. Release [SHIFT], type the next number and continue. You'll never have to move your typing hand from the keypad. That makes entry easier.

As I said, this trick goes all the way back to the original PC keyboard, which didn't have a separate set of cursor keys. Back then [SHIFT] actually reversed the Num Lock setting in either direction. Since SHIFT now works to mark multiple cells in a spreadsheet, the toggling only works in one direction--when Num Lock is ON and you want to turn it off for a second.

Also, when Num Lock is OFF, holding [SHIFT] and one of the arrow keys for [UP][DOWN][LEFT][RIGHT] lets you select additional cells.

Photo Courtesy: Dave Bradley

I was a member of the keyboard task force that met within the PC Company in 1985 to design a new keyboard. That's the one that eventually became the standard keyboard of the IBM PS/2 family of computers in 1987.

This group of engineers included all of the keyboard experts within both the PC company and IBM. But, among those 10 people, I'm pretty sure I was the only one who knew about the [SHIFT] Num Lock combo I just told you about

So this function was obscure even with the experts in the 1980s. And I bet it's mostly unknown today.

I saw one of your tips by Paul Somerson--a combo I also invented, to display the cent symbol--and it made me think BYTE readers would like this type of thing.

By the way, I'm also known in engineering circles as Dr. Dave, the inventor of [CTRL][ALT][DEL]. For my recap of how [CTRL][ALT][DEL] came about, see the video below. Watch Bill Gates' expression at the end. It's classic.

Welcome back, BYTE.

Based in North Carolina, Dave Bradley was on the original IBM Personal Computer (PC) Model 5150 development team.

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