BTW, this is from 2013, and mentioned in the Wikipedia article on "Control-Alt-Delete".

> Later in an interview, Bradley said he didn't understand why Gates and Microsoft decided to make it a login feature, adding that "I guess it made sense for them."

I thought it was because it's a secure attention sequence to prevent login spoofing, since that cannot be emulated software in userland. Certainly the WP page suggests that.

That was my understanding and I see no problem with it.

Indeed, it was an important security feature. I think Bill is just saying that they should've got PC manfacturers to add a "Log On" key to the keyboard which they could've caught in the OS in the same way as Ctrl+Alt+Del.

I think the only other key that has this low-level trap feature is SysRq (usually Alt+PrintScreen), which, of course, Linux uses for [Magic SysRq](https://en.wikipedia.org/wiki/Magic_SysRq_key).

Now that I think of it, "Press 'System Request' to log on" has a nice ring to it. A shame it was it in the shifted position on IBM PC keyboards.

There's no special "low level feature" when your keyboard hangs off a serial bus (as did pm keyboards from the start. XT, AT, PS/2, USB...) As far as I know also C-A-Del was just the default in the original bios keyboard handler to trigger a quick reboot.

Windows, for example, has a (by default disabled) feature to trigger a kernel panic on Ctrl+Scroll lock. Also purely software based and just as arbitrary in its choice of keys. And also very useful to recover from an otherwise stuck system.

(As an aside, why do you say "Bill" instead of "Gates", or "BillG" as I believe Microsoft employees refer to him?)

Yes, he said that. If he really believed it then why didn't the Microsoft Natural keyboard, which added the Windows logo keys and the menu key, also add a special "login" button?

>this is from 2013

And repeated ad nauseum.

I don't see a problem with using it for the reasons they used it.

In a related video, if you've never seen it, this one is great, with the original Ctrl-Alt-Delete programmer (David Bradley) on stage with Bill Gates...

https://www.youtube.com/watch?v=K_lg7w8gAXQ

Gates provides an odd answer, and somewhat shifting blame.

He's essentially saying he would have preferred a single "Reboot" key on the keyboard, then would have used that to begin the login sequence?

XP and similar OSes could be configured so you had to enter Ctrl+Alt+Del before you could log on. It's called a 'secure attention sequence' [1] and the idea is it makes sure the user only enters their password into the login box - not a fake login box on a full screen website or something like that. Fairly easy for a joker in a school computer lab to do that.

At least one computer has been released with a dedicated secure attention button - the NEC Versa LitePad was a ~2003 tablet running Windows XP. It had no physical keyboard, relying instead on handwriting recognition or an on screen keyboard, but it had a dedicated button with a picture of a key on to begin the login sequence. It's the middle button at the top in [2].

(if you're wondering, the other buttons were rotate screen, escape, Fn, up/down, power on/off and wireless on/off)

[1] https://en.wikipedia.org/wiki/Secure_attention_key [2] http://digichar.com/imgs/a/b/i/w/q/nec_versa_litepad_vl___pa...

Yes, a single hardware SAK would have been much preferable. Given Microsoft's predilection for adding buttons for all other sorts of things in the 90's, I don't understand why this never happened.

What is a 'SAK'? (EDIT: Oh, michaelt (https://news.ycombinator.com/item?id=9987050 )'s link points out that it is a 'secure attention key'.)

> Given Microsoft's predilection for adding buttons for all other sorts of things in the 90's, I don't understand why this never happened.

Probably because those other buttons were 'just' meant to add functionality, so that users without them would just get a less-assisted-but-still-functional environment; whereas requiring a special key on a keyboard just to log in would have left legacy users unable to do so, a situation which (they and therefore) Microsoft would surely find untenable.