Scroll Lock - The Secret Key THEY Don't Want You to Press!

Finally, a guy sitting in his truck who knows what he's talking about.

Scroll Lock was essentially a prank key at an office I worked in. For data security, office policy was that you were supposed to lock your computer if you stepped away from it. So if someone was away from their pc and it was unlocked then pressing the scroll lock button was one of the possible consequences. We used excel extensively, and coming back to find your computer behaving totally weirdly when trying to cursor around caught all of us out the first time it happened to us.

I'm old enough to have: learned to type on a mechanical typewriter, then "re-learned" on an electric, then eventually discovered the marvels of PC word-processing. I think I did at one point actively use the scroll-lock functionality as part of crunching through massive spreadsheet work. But as began to watch this video, I had forgotten that and had a blank as to what Scroll-Lock actually did. Now reminded, I have come full circle twice: a figure eight!

Yes, you are 100% correct at 2:58 as to the purpose of the Scroll Lock key. Actually, Scroll Lock was on IBM mainframe terminals (3277) long before microcomputers were a thing (even before the Imsai 8080 and the Altair 8080). I suspect they ended up standard on modern PCs because IBM put the Scroll Lock key on their original IBM PC keyboard to be compatible with mainframes for some applications and it just became a legacy feature.

As a blind computer user, I enjoy learning everything related to keyboard shortcuts. After all, even though screen reading programs can speak what is under the mouse cursor, we tend to use the keyboard much more. So I surely enjoyed these informations on scroll lock!

Thank you Dave for risking your life to bring this information to us.

In the IBM PC world, during the early PC/XT era, all the lock keys worked solely from the keyboard. The keyboard interface did not support two way communications. All information flowed from the keyboard to the computer. The state of the locks was entirely in the domain of the keyboard itself. Most of them did this through on board logic controllers, however there are the odd keyboards that used actual locking keys that stayed in a depressed state upon tapping. This all changed in 1984 with the introduction of the IBM PC/AT. A new protocol was introduced via the addition of a Intel 8042 controller. This provided two way communications allow the PC to change not only the lock state of the keyboard but also allowed independent control of the indicator LEDs. The i8042 is long gone in modern PCs, but is still emulated in current PS/2 and USB interfaces. All this being said the history of all the lock keys goes far beyond the IBM's original PC over 40 years ago.

I did know about the standard/approved function of ScrollLock, but I'm surprised you didn't mention its (slightly) more modern use: it was the default switch key for nearly all hardware KVM switches from the 90s through the 10s or so, and - though I haven't needed a KVM switch in quite a while - I bet it's still used that way on current models. Drove me nuts when keyboards started popping up without a Scroll Lock key! (For those unfamiliar: a KVM switch allows you to operate multiple computers with a single Keyboard, Video monitor, and Mouse; you either press a button on the KVM, or more commonly press Scroll Lock on the keyboard, to switch between them. Very useful in server rooms/data centers or on the workbench of a PC builder/repair shop.)

I use Scroll Lock and Pause / Break as mute buttons in voice chat apps. I'm glad they exist because they're perfectly suited to this purpose; otherwise unused and located away from keys you might actually want to press. And Scroll Lock provides a nice light to tell me when I'm muted. The reason they don't set caps lock on or off with password fields is because the caps lock is a low level system function and doing so would allow applications dangerous levels of access. You can normally turn caps lock on and off unless the system is completely frozen.

Before there was Windows, the scroll lock was used to keep the text on the screen from scrolling. It allowed the user to freeze the output before it scrolled off the top of the screen. Yes, you can pipe it into MORE, but that is not always an option.

At work, when someone accidentally hits Scroll Lock, it basically locks our software from typing or doing anything. Hitting it by accident became such a common annoyance that I eventually took my pocket knife and popped off each Scroll Lock key off of every keyboard in the building.

Looking forward to the deep dive into the "Sys Rq" key next :)

These type of “secret history of… “ are my favourite episodes. 10 minutes is perfect length for a quick fyi type video. 20 minutes also works for more in-depth topics, just more difficult to put it on as soon as you uploaded it. Thank you Dave. Keep the interesting stories coming ✊

Thanks for sharing your truck. Took me back to the '74 GMC Sierra 1500 that was once in the family. The shot of your bed and the wooden lined floor took me back... I had forgotten that they were made like that. Thanks for stirring the memories. Now I have to like the video. Haha.

As someone who relies heavily on the Pause|Break key, I am very glad to know what Scroll Lock does. However, I vaguely recall that Scroll Lock would prevent the document from scrolling in WordPerfect 5.1 for DOS. Unfortunately, I can no longer verify this.

The Pause key is even more mysterious to me. A little story about it: I had a mentor that tought me many tricks about computers and windows. At one time, we wanted to install Windows Server (some incarnation of it) for a customer. However, we run into some sort of problem with the combination of the hardware, CD key and installation CD that the customer had. We couldn't use it (dunno remember the exact reason). What we did, IIRC, was to boot up with a working (for the hardware in question) CD. Just enough for the server to boot up the installation CD. THEN hitting the pause key to pause it all, swap CD's so that we had the CD with the right contents and then resume the whole thing with another press att pause. I guess it worked due to several things: both installation CDs had similar content (but only wan that we could use for the boot/keycheck) - and the timing when hitting pause - so that the bootloader and whatever was needed was actually loaded. But it worked, it really did. That way, instead of having no usable installation media until a costly and time consuming new CD arrived, we used what we had at hand and continued.

I can't stop laughing about the conspiracy style intro. Marvelous! And a good piece of history too. Your accent sounds very "if Canadians were from The South", which I find very amusing.

Beautiful truck Dave. You are a talented fella for sure. In my retirement I started making scratch built stationary steam engines. Tons of fun and it helps pass those long winters in Upstate NY. Keep up the great work!

I haven't used the Scroll Lock key since I gave up programming in DOS. I used it only to keep my screen echo from scrolling off the screen too fast, anyway. My current keyboard doesn't even have a scroll lock key, replacing that position on my keyboard with an LED key that changes the color of my keyboard backlight. Beautiful truck. I'm not much of an auto guy, but I appreciate the craftsmanship.

Thanks Dave! Fantastic restoration work on the truck! It's definitely heart-warming to see a 52-year old truck running in a sublime state and looking as if it just rolled off the factory-line!