back to article Bill Gates: Yes, Ctrl-Alt-Del salute was a MISTAKE

Microsoft supremo Bill Gates has claimed that the ctrl-alt-del keystroke - once a way of admitting defeat in the face of crashing software - was a mistake all along. Anyone with a passing knowledge of PCs will remember hammering those three keys to forcefully reboot the computer as code locked up. Some people even called the …


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  1. HCV


    "Microsoft. We're so confident that you'll need to reboot, we want a DEDICATED KEY for it."

    We Unix people laughed and laughed when one of the most vaunted features of Windows 2000 was that it would go *so long* without rebooting -- like *30 days* -- that they built in a special "reboot at a regular interval" feature.

    Which, of course, we would have called "cron". If we thought that it was a good idea in the first place.

    1. asdf

      Re: WAT

      Yes a nearly crash proof OS was 1970s technology (sure someone will point out even earlier probably) but Billy still can buy any yacht he wants.

      1. Hud Dunlap


        But can he win the America's cup?

    2. Anonymous Coward
      Anonymous Coward

      Re: WAT

      Yes, just not everybody could afford a Unix machine then, and its very expensive applications, and most Unix users worked on system they didn't pay for, but their universities and companies did. Thus most people were happy with cheaper machines although sometimes you needed a reboot....

      1. ThomH

        Re: WAT

        MS-DOS and early versions of Windows were designed for a processor without protection domains. You couldn't do anything to protect the OS against a crashing process. In Windows you not only couldn't protect the OS but you had to rely on third-party hardware providers writing good drivers.

        I guess to the extent that Microsoft deserve criticism, it's not transitioning their OS fast enough as the x86 architecture matured. With computer sales growing exponentially throughout the 80s and early 90s that made legacy software compatibility much more of a problem than it needed to be. But probably they genuinely believed OS/2 would happen.

        1. Anonymous Coward

          Re: to the extent that Microsoft deserve criticism?

          There is no "extent." There is no limit to the criticism that Microsoft deserves, especially for those dreadful "Early" versions (say up to W2K) each of which it expected us to pay to escape.

          1. Tinker Tailor Soldier

            Re: to the extent that Microsoft deserve criticism?

            Well, at least MS had the excuse that the processors it ran on 8086 and 8088 didn't have mem protection. Apple COULD have wired in protection for the 68000 (Mac onward) but elected not to due to cost. OS/2 used mem protection from the 286 onwards. NT, based on the 386 did too.

            The consumer OS's didn't. Because:

            1. RAM was expensive, and the memory protected OS's (OS/2 and NT) both needed more of it.

            2. Many apps didn't respect process boundaries and crashed anyway, e.g. directly accessed interrupt tables to hook stuff. So, to keep compatible you couldn't protect memory.

            But, rewrite history all you like?

            1. ThomH

              Re: to the extent that Microsoft deserve criticism? (@Tinker Tailor Soldier)

              I'm unclear who you think is rewriting history — essentially both the PC and the Mac came from companies that understood protected memory and MMUs perfectly but choose to omit the hardware for cost purposes. There was an MMU in the Lisa, there wasn't in the Mac. There was one in any number of IBM machines going back decades, there wasn't in the PC.

              The history of Apple's multiple subsequent internal OS development screw-ups is interesting but quite distinct from Microsoft's errors. The stories start similarly but Apple get to the point between 6 and 7 where the resources were such that they could have afforded just to run multiple instances of 6 simultaneously and preemptively to multitasking properly with memory protection on those devices with MMUs, but instead they double down on cooperative multitasking and spend the newly spare resources on rewriting a bunch of things in C. After the PowerPC move they have a full preemptive, protected memory handling nano-kernel which is used to run the existing OS. For quite a while large parts of the stack remained in 68000 code and just ran through an emulator — they spent engineering time getting the emulator down small enough to fit entirely within the processor cache because it was a more effective way to transition than dealing with the OS proper.

            2. Tom 13

              Re: But, rewrite history all you like?

              I wouldn't say rewriting. That's your interpretation.

              As far as your point #2 goes, Apps didn't respect the boundary because they didn't HAVE to. If they'd been forced to respect it, we'd probably all be better off now.

              And yes, I recall when memory was super-expensive. I also recall being sorely disappointed when having finally plopped down a huge wad so I could buy enough to have a proper RAM disk to speed up my system, it turned out the VESA local bus disk controller I had already installed made its addition barely noticeable.

          2. Hans 1

            Re: to the extent that Microsoft deserve criticism?


            Why just the dreadful early versions ? True, w2k was good - by MS standards, that is - but anything before that was crap and anything after it was bloatware, with the notable exceptions of Windows Me, Vista and 8, which are crap (latter two being both bloated crap).

          3. Anonymous Coward
            Anonymous Coward

            Re: to the extent that Microsoft deserve criticism?

            @Thad - I think you're re-writing history there - Windows was the software that allowed people to break the stranglehold of Big Iron Unix on the datacentre. At the time there was simply no need to use Unix for many tasks, it was over engineered, but it took Windows (and to a lesser extend OS/2 and Netware) to break into the datacentre and do those commodity tasks at commodity prices.

        2. tom dial Silver badge

          Re: WAT

          1. Early Unix machines also lacked protected memory, as did early versions of Minix. Both were more stable than MS-DOS before 6.2.

          2. OS/2 did happen, in a technical sense at least, and it ran Windows applications better and more reliably than Windows did.

          1. Neil 44

            Re: WAT

            The Interdata 7/32 was a very early Unix platform (the first non-AT&T according to K&R Ed 1!)

            It certainly had memory protection and used user and system level interrupts to process things. Processes were isolated from each other.

            (admission time: there weren't any 7/32s around when I joined the company, but there were the slightly newer 8/32's!)

        3. Tom 13

          @ThomH: You were doing ok

          until that very last statement. Their dealings with IBM on OS/2 even more than their dealings with Lotus 1-2-3 forever cemented the "Microshaft" nickname.

          1. ThomH

            Re: @ThomH: You were doing ok (@Tom 13)

            I buy the version where the surprise success of Windows gave Microsoft the idea to renege — they stabbed their partner in the back as soon as an opportunity arose but had not expected or been planning for the opportunity.

            I can't think of another reason why they'd create the multitasking, new executable DOS 4, barely license it and then push all its code off into OS/2, subsequently picking up DOS from the version 3 code base.

        4. Anonymous Coward
          Anonymous Coward

          Re: WAT

          Many computers were like that. They added MMUs and all sorts of things later.

          But adding protection and things to stop the machine crashing almost parallels safety protections on cars. It just resulted in worse coding just like a safer car results in worse driving.

          Of course now we're glad of mem protection because of malware and keeping that in check.

    3. Anonymous Coward
      Anonymous Coward

      Re: WAT

      Windows NT4 was quite capable of going 30 days without reboot, w2k could go far longer. I am not aware of any "reboot at a regular interval feature" unless someone created their own scheduler job. It's certainly not built in functionality.

      At around the time of NT4, I had a pretty good Sun Sparc UNIX workstation on my desk, it cost around £10k, at the company I worked for at the time we could get fully licensed NT4 Servers running on Compaq proliant hardware for half that price. They were good servers, too. Consequently UNIX servers started their inexorable departure from the datacentre. Proprietary RISC Unix doesn't deliver the bang for buck of either Windows or Linux on Intel. What's the point of being able to stay up for years on end, if no-one can afford it and the alternatives are good enough, particularly with modern clustering.

      1. Carl

        Re: WAT

        I've seen many UNIX/Linux machines over my career with uptimes of 1000+ days.

        I even ran a mailserver on an old 386/FreeBSD that had 200+ days of uptime until a power snafu happened.

        But my favourite "uptime" story is the (possibly apocryphal) one about the Novell Netware box that nobody could find. It worked, responded to pings etc, but nobody had any clue where exactly it was. It was finally discovered, amongst other "old" kit behind a wall that contractors had put in about 5 years earlier.

    4. BillG

      Re: WAT

      30 days? C'mon, where'd you get that? I had a Windows 2000 laptop that ran for 14 months before the battery died during a winter power outage.

      1. Anonymous Coward
        Anonymous Coward

        Re: WAT


        (a) you are full of sh1t

        (b) you never did any kind of update

        (c) you never ran any software or

        (d) you never plugged it into a network

        My money is on all 4

    5. 9Rune5

      Re: WAT

      "Microsoft. We're so confident that you'll need to reboot, we want a DEDICATED KEY for it."

      Uhm, no.

      BillG talked about a dedicated key to produce the _login_ screen. I.e. Windows NT, not 16-bit Windows or DOS.

    6. DrXym

      Re: WAT

      Even systems like Minix, AmigaOS (on the 68000) and MacOS (68000) implemented a 3 fingered salute for those when a rogue process stomped on the kernel and rendered the whole machine unresponsive.

      The issue is not the OS but the CPU's lack of memory protection.

    7. Anonymous Coward
      Anonymous Coward

      Reboot Jockeys

      Where I worked we called the windows "sys admins" reboot jockeys. A name that they fully deserved. It was not uncommon, at the end of the day, to see them drop a windows machine from the load balancer, reboot and then put it back in again and then work their way through all of them like this in the hope that they would last overnight. The idea of investigating why something went wrong never entered their head.

      A dozen years later and things have improved significantly. Most of them now look to perform a reboot as a last resort rather than a first and they will actually investigate the cause when something goes wrong.

  2. HCV

    "Oops. Did hitting that mess something up for you?"

    And I would like to add that asking for a single dedicated "BORK YOUR COMPUTER" key on a computer keyboard may be the single stupidest thing I have ever heard a multizillionaire brag about.

    1. Anonymous Coward
      Anonymous Coward

      Re: "Oops. Did hitting that mess something up for you?"

      There's already such a key and it is the PC power switch! (I know Ctrl+Alt+Del performs a soft reboot...)

      Anyway a single key to reboot a PC would have been really very, very dangerous - and silly. The IBM guy did a good work selecting a combination you can't use by mistake.

      1. Tom 7

        Re: "Oops. Did hitting that mess something up for you?"

        would have been really very, very dangerous ???? You mean like that key that you hit and it ignores everything else until it goes to sleep - ten seconds after you hit the power switch so when you power up again whatever was running needs a re-install.

        A Windows keyboard - smells less than pouring your beer into the fan but not as nice.

        1. M Gale

          Re: "Oops. Did hitting that mess something up for you?"

          A Windows keyboard - smells less than pouring your beer into the fan but not as nice.

          Power buttons on the keyboard is something Apple Macs had first. It's just as fucking annoying on them, too. Think different? Yeah, right.

          Amusingly, the keyboard I'm using thankfully has no such retardedness on it. Model? Microsoft Wireless Keyboard 800.

      2. Chad H.

        Re: "Oops. Did hitting that mess something up for you?"

        Reset button was usually right there on the chasis.

        1. Caesarius

          Re: "Oops. Did hitting that mess something up for you?"

          Reset button was usually right there on the chassis.

          I remember a MAC with the reset button at "mouse height". The number of people in my lab who accidentally ran their mouse into it. Disbelief, cold sweat, realisation, anger, and finally the search for something like a rubber (1) to sit in front of it.

          (1) No, John Doe: that's a pencil eraser

      3. Anonymous Coward
        Anonymous Coward

        Re: the PC power switch!

        I've seen a server downed by a foolish knee movement, but generally, one's finger wandering doesn't extend off the keyboard to the case itself. Not unless one is really kinky.

        1. Nigel 11

          Re: the PC power switch!

          In the early days of PCs, the power switch sometimes protruded proud of the case. Back then it was a hard mains switch, not a soft switch. I've seen major damage caused by pushing the keyboard back against the idiot-designed case. Later, the power switch (and reset button) were always recessed. Ease-of-use is not always a good thing. Big red switches ought to come with Mollyguards. Needing three fingers for C/A/D was definitely good design not bad. It's pretty much impossible to C/A/D by any kind of mistake.

          1. Daniel B.

            The PC KEYBOARD power switch

            Soooo.... Nobody here remembers the retarded keyboards from the mid-00's with the awful "shutdown" key? Especially the ones that had a row of "shutdown, suspend, sleep" keys right below the "insert, delete, hone/end" keys. So you could be trying to press End, but press the cursed shutdown key, which would send an unstoppable shutdown command to Windows! Weeeeee!!

            I usually had an unsaved Notepad session somewhere, so that I could click Cancel on the save dialog to stop the process. Though if you took too long, all the other apps would have been killed by the OS anyway... :(

            1. Rattus Rattus

              Re: The PC KEYBOARD power switch

              Oh gods, yes. I had one of those fucking things. Most ridiculous idea for a keyboard. I ended up removing those three keys physically after one unintended power-cycle too many.

    2. Mat Child

      Re: "Oops. Did hitting that mess something up for you?"

      The BBC micro's BREAK key basically was what Gates was asking for.

      Although you could intercept the call and stop it from performing the reset.

      1. h3

        Re: "Oops. Did hitting that mess something up for you?"

        It didn't work on its own though only as a key combination. (With either shift or control).

      2. Charles Manning

        Re: "Oops. Did hitting that mess something up for you?"

        IIRC, BREAK was more like CtrlC than the CtlAltDel

        1. Yet Another Commentard

          Re: "Oops. Did hitting that mess something up for you?"

          Esc stopped the programme (error 17, easy to stop) Break did a "soft" reset, ctrl+break did a "hard" reset IIRC.

          The Amiga had a similar one I think - was it ctrl+amiga+amiga?

      3. HippyFreetard

        *KEY 10 "OLD|MRUN|M"

        Can't believe I remember that - was one of the ways to annoy BASIC programmers. Ctrl+Break did the trick :)

        1. Anonymous Coward
          Anonymous Coward

          Re: *KEY 10 "OLD|MRUN|M"

          Of course the BBC Master had a "Break Lock" which could physically prevent you from pressing the Break key.

    3. NullReference Exception

      Re: "Oops. Did hitting that mess something up for you?"

      The original Apple ][ and ][+ had a "RESET" key on the top right of the keyboard, right above the Return (i.e. Enter) key. It was very easy to hit it by mistake and lose all your work. Many users would make it harder to hit RESET by putting rubber washers under the keycap or using various other tricks. Eventually, someone at Apple realized that single-key RESET was NOT a good idea, and from the Apple //e onwards the design was changed so you had to press Ctrl+RESET to do a reset.

      Bill & Co used to write stuff for the Apple... guess he forgot about this!

    4. deshepherd

      Re: "Oops. Did hitting that mess something up for you?"

      And I would like to add that asking for a single dedicated "BORK YOUR COMPUTER" key on a computer keyboard may be the single stupidest thing I have ever heard a multizillionaire brag about.

      Around the time MS-DOS was appearing there were computers with single key "resets" - e.g. the BBC Micro had the "Break" button which was "conveniently" sitting at the top right of the keyboard right next to keys that you would use in normal usage. This meant it was quite possible to press it by mistake .... think as a result a market developed for plastic covers which sat over the break key preventing it being pressed.

      I always though that having to press 3 keys (and 3 keys that needed both hands on most keyboards) was an eminently sensible idea to make it clear you were really meaning to reset the PC. Later when C-A-D became the way to bring up the login menu in later versions of windows was probaly more problematic as (a) you wanted to login in - what else where you going to do at that point and (b) using a key combination that was (at least subconciously) associated with "help, my PC has gone wrong" with an action that said "I've just turned my PC on, lets get started" seemed counter intuitive.

  3. Joe User

    Ignore the obvious choice

    "Guy who did IBM keyboard design didn't want to give us our single button."

    Was there something wrong with using the SysRq (System Request) key? It was the obvious choice, and that key has been around since the PC/AT days.

    1. Don Jefe

      Re: Ignore the obvious choice

      I think Gates wanted a single, dedicated, button because it would make the keyboards different. Great branding strategy, kind of dumb from systems design standpoint though. Computers, by default, are the great reuse kings of everything. Building single use, most anything, into a computer is kind of dumb. It goes against everything a computer represents.

    2. jaywin

      Re: Ignore the obvious choice

      That's used under Windows though.

      Pause/Break on the other hand... "Hello, IT" "My computer has broken / paused. Fix it" "Just push the Pause / Break button" "Many thanks good sir"

      1. Tannin

        Re: Ignore the obvious choice

        Joe User : Was there something wrong with using the SysRq (System Request) key? It was the obvious choice, and that key has been around since the PC/AT days.

        jaywin: That's used under Windows though.

        This was 1981. Windows did not exist. DOS ruled. The dreadful first release of the Windows operating environment (i.e., a type of DOS application) came along just before 1986, and it did not become truly usable and widely popular until v 3.1 in 1992 - 11 years after the standard IBM keyboard was first manufactured.

        1. John Smith 19 Gold badge

          Re: Ignore the obvious choice

          "The dreadful first release of the Windows operating environment (i.e., a type of DOS application) came along just before 1986, and it did not become truly usable and widely popular until v 3.1 in 1992 - 11 years after the standard IBM keyboard was first manufactured."

          And still being co-operativemulti-tasking, like the Archimedes IIRC, but without MS being very honest about it one rogue application could still hang your computer.

          Thanks Microsoft.

    3. Don Jefe

      Re: Ignore the obvious choice

      Or used the PrntScrn button instead. They could have made some big time partnerships with ink manufacturers at the same time.

    4. HCV

      Re: Ignore the obvious choice

      Er, yes, but the PC/AT wasn't around in the PC days. The PC-101 keyboard came out several years after the original PC.

      1. Steve the Cynic

        Re: Ignore the obvious choice

        "Er, yes, but the PC/AT wasn't around in the PC days. The PC-101 keyboard came out several years after the original PC."

        Read. History. Carefully.

        The original PC (the 5150) came out in late '81, with an 83-key keyboard. It was superseded in 1983 by the PC/XT (the 5160) which used the same keyboard.

        The PC/AT (the 5170) came out in 1984, using an 84-key keyboard, the 84th key being SysRq. The keyboard connection was not compatible in either direction with the PC / PC/XT keyboard connection, except that many third-party keyboards had converter switches.

        The 101/102-key layouts reached us in 1987 with the arrival of the PS/2s.

        1. Nick Ryan Silver badge

          Re: Ignore the obvious choice

          It was worse when MS decided that Windows keys should be added to PC keyboards. But no ****ing help key, instead an arbitrary function key was "commonly" used instead. On the other hand, prior to this time the VT100 style system keyboard had specific Help keys... probably from the earlier as well, but I daren't try to remember pre VT-100 layouts.

          So along with the left and right windows keys and the menu key, they really missed the boat on specifying something useful, the Help key. And the "Any" key as well, that would have saved a lot of time hunting around for it... :)

        2. Peter Gathercole Silver badge

          Re: Ignore the obvious choice @Steve the Cynic

          I believe that the IBM Enhanced Keyboard was available for the PC/AT as an option from launch in 1984, before the PS/2. Wikipedia states that the manufacture of the Model M keyboard started in 1984.

          I'm fairly certain that the first PC/ATs (early 6MHz models) bought by the Polytechnic I worked at in the 80's all came with UK model 102 key keyboards.

    5. rurwin

      Re: Ignore the obvious choice

      IIRC, SysRq was used by OS/2, and it is still used by Linux.

      Of course modern OSs are more complex than DOS, and you don't want to shut them down without stopping all the processes and syching all the disks. So hold down Ctrl-Alt-SyqRq and type (slowly)

      r - Put the keyboard into a sensible mode

      s - Sync the disks

      e - Terminate all processes

      i - In case some processes are hung ignoring signals, kill them all with a big axe.

      s - Sync the disks again, to be sure, to be sure.

      u - Unmount all disks

      b - Reboot (or o to switch off).

      Raising Skinny Elephants Is Sometimes Utterly Boring

      1. Anonymous Coward
        Anonymous Coward

        Re: Raising Skinny Elephants

        Absolutely no chance of hitting those key combinations by accident --- or of remembering even the mnemonic for something so very rarely used. I keep it written down on the back of my pad.

        1. lurker

          Re: Raising Skinny Elephants

          "Reboot Even If System Utterly Broken" is the one I recall.

  4. stephajn

    The one key idea...

    ...Glad it never took off.

    The keyboards that have the half moon button on them to suspend or sleep the computer were bad enough. On my HP keyboard I am using, that key is DIRECTLY next to the tilde key and is quite long. One false move with the left pinky near the ~ key...OH DAMN!!!!!

    1. Anonymous Coward
      Anonymous Coward

      Re: The one key idea...

      Crtl + F4 - close a window

      Fn + F4 - hibernate

      Thanks Lenovo for switching those two keys around, makes me laugh every time I do it. Luckily I use a full sized keyboard most of the time, rather the laptop one.

    2. P. Lee

      Re: The one key idea...

      Billy got his share of bad ideas anyway... "Delete" next to "rename" (not separated from everything) in file manager? Doh!

      1. Thomas Gray

        Re: Poor menu arrangement

        And "Format" next to "Eject" for USB devices....

    3. Sureo

      Re: The one key idea...

      I used to pop the caps off those keys to avoid hitting them by mistake.

      1. Nick Ryan Silver badge

        Re: The one key idea...

        I used to do that as well. It was one hell of a fucktard idea, putting sleep and power keys onto keyboards. After all, it's not as if keys on the keyboard get leant on, mishit, papers put onto or anything else is it?

        Almost as good an idea as installing games and 3D screensavers onto server systems by default...

  5. Anonymous Coward
    Anonymous Coward

    That's just so Acorn...

    Bill Gates can't have spent much time playing computer games loaded from tape drives...

    We got so frustated with accidentally knocking the "Break" key on our acorn electron that we cut the track on the circuit board and soldered on a couple of wires attached at the other end to a sliding switch, which we bolted to the side of the case. From then on, reboots only happened when required.

    Many happy hours of playing "$wag" and "Bandits at 3 o'clock"....

  6. Anonymous Coward
    Anonymous Coward


    Why was it so important that you press a key [sequence] to log into NT in the first place?

    Was this some sort of power saving thing so you could wait for an interrupt instead of poll the keyboard, or something?

    1. BlueGreen

      Re: Confused - it's a security thang

      My understanding is that it generated a non-maskable interrupt that was guaranteed to be responded to only by the windows OS. Any prog running as a spoof, ready to take your login details and Do Evil with them would be guaranteed bypassed, and this is one of the reasons windows earned a particular security rating (ref, which I need to read myself <>):


      When NT earned its C2 security rating, NCSC also recognized NT as meeting two requirements of B-level security: Trusted Path functionality and Trusted Facility Management functionality. Trusted Path functionality prevents Trojan horse programs from intercepting a user's name and password as the user logs on. NT's Trusted Path functionality exists in the form of its Ctrl+Alt+Del logon-attention sequence. This sequence of keystrokes, the Secure Attention Sequence (SAS), causes an NT logon dialog box to pop up, which initializes a process that helps NT recognize would-be Trojan horses. NT bypasses any Trojan horse that presents a fake logon dialog when a user enters the attention sequence.


      From what very little I understand, I don't see why it was not adopted by linux.

      1. Anonymous Coward
        Anonymous Coward

        Re: Confused - it's a security thang

        They lied... under DOS and Win16 Ctrl-Alt-Del is handled by BIOS, on NT it is handled by the NT kernel... it does however travel thru the keyboard driver and can be intercepted there.

        Ctrl-Alt-Del functionality is in software as all key combinations EXCEPT one: SysRq.

        NMI on PC hardware is ONLY generated by a memory parity error, all other interrupts are maskable.

        It is not secure... that is just an illusion on Windows NT.

        1. Ken Hagan Gold badge

          Re: Confused - it's a security thang

          "it does however travel thru the keyboard driver and can be intercepted there."

          If you have malware running in your kernel then you've already lost.

          The security offered by Ctrl+Alt+Del on NT is not illusory, and if you ignored all Microsoft's pressure to run your browser and email client as Administrator then the security offered by the rest of NT wasn't illusory either.

      2. Euripides Pants

        Re: Confused - it's a security thang

        "From what very little I understand, I don't see why it was not adopted by linux."

        Probably because it would be "F#CK!NG POINTLESS" according to Linus T.

        1. Anonymous Coward

          Re: F#CK!NG POINTLESS"

          Hmmm ... puts it a lot better than I just did!

      3. Anonymous Coward
        Anonymous Coward

        Re: Confused - it's a security thang

        > When NT earned its C2 security rating, NCSC also recognized NT as meeting two requirements of B-level security

        Right, but when they "earned" the rating one of the requirements was to disable networking.

        Not that useful of a box, but, look, it's C2!

        1. Anonymous Coward
          Anonymous Coward

          Re: Confused - it's a security thang

          @AC 21:14 - You say that like anyone could achieve C2 rating if they didn't have a network connection. This is simply not the case, many systems wouldn't even begin to start ticking the required boxes network or no. I'm still pretty certain I could achieve a fair amount of work on a non-networked computer, especially as they all had disk drives in those days.

      4. Flocke Kroes Silver badge

        @BlueGreen: SAK (and much more) is in Linux

        <ctrl><alt><backspace> Terminates the X server. This will cause the death of the window manager and any program it started. Most installations have a display manager that will restart the X server with a login program. Read the xorg man page for how to change the key combination or disable. The most common display managers are gdm and kdm. Both are very configurable.

        <ctrl><alt><delete> can be intercepted by software that puts the keyboard into raw mode. Read the /proc/sys/kernel/ctrl-alt-del section of the proc man page to set the tty layer's behaviour if the keyboard is not in raw mode. The default behaviour is to send SIGINT to process 1. This is normally init, which will execute the command specified for ctrlaltdel in /etc/inittab.

        <alt><sysreq>H Outputs the help for sysreq keys to the current virtual console. The one you are looking for is the secure acces key: <alt><sysreq>k - unless you changed the keyboard translation tables with loadkeys. The documentation is here. SAK cannot be intercepted by putting the keyboard into raw mode. It kills all processes on the current virtual terminal. Unless configured otherwise, init will spot this and run login on the terminal.

        There are other handy things you can do with the sysreq key like remount all file systems read only and sync all the disks - unless the functionality was disabled from /proc/sys/kernel/sysrq.

      5. Mother Hubbard

        Re: Confused - it's a security thang

        > From what very little I understand, I don't see why it was not adopted by linux.

        By default - in a Desktop mode it does - brings up a log-out screen while you're in a session. But it can be anything you want it to be (

        For DOS-like brilliance you can either create /etc/event.d/control-alt-delete with this content (exec /sbin/shutdown -r now "Control-Alt-Delete pressed") or add the following content to /etc/inittab (ca:12345:ctrlaltdel:/sbin/shutdown -r now "Control-Alt-Delete pressed").

        For Windows-like brilliance you can assign the key binding using Metacity or Compiz to bring up the system monitor (gnome-system-monitor) like in this example ( or take the desktop session back to the login screen (logout-gnome="gnome-session-save --force-logout") via this example (

        Linux's true equivalent is Alt-SysReq-Func;

      6. Anonymous Coward

        Re: why it was not adopted by linux.

        Linux is a multi-user operating system, even if PC installations may not often be used as such. Imagine what life would be like if one user among many could reboot a system just because their program had locked up!

    2. Robert Forsyth

      Re: Confused

      IIRC it was pseudo security

      If someone was running a fake login screen with password snaffling, then pressing Ctl-Alt-Del would end the fake program, in theory .

    3. diodesign (Written by Reg staff) Silver badge

      Re: Confused

      AIUI hitting the keys triggers a normal interrupt as usual (there's nothing special about it) but (at least today) the winlogin process is hooked low into the system (user32.dll) to pounce on the c-a-d sequence and do its thing before any other software can get a look in.

      This last point is important: you want to know that stuff you're seeing on-screen (eg, username and password prompt) is from official, trusted software and not a bogus application pretending to be the winlogin process.

      I've added some links if that helps.


    4. Sandtitz Silver badge

      Re: Confused

      >Why was it so important that you press a key [sequence] to log into NT in the first place?

      I'm more curious why all(?) the Linux distros do a graceful reboot when CAD is pressed in console mode. I know it can be disabled but why is this "power button" feature enabled in the first place?

  7. Stephen Channell

    there were bigger mistakes

    like using the "\" key instead of "/" for file delimiters with PCDOS 2 to avoid maybe hundreds of people having to change their batch files..

    What made Ctrl-Alt-Del special was that it sent a different interrupt to the PC that could implement a soft restart... Windows adopted it to mask the reset.

    not wishing to detract from the Bill bashing, but... I think Bill wanted a button like the one on the AT&T 7300 Unix PC that had a soft restart button

  8. Matt Piechota


    I'm guessing Bill Gates has never owned a cat.

    1. Ian 55

      Re: Meow.

      It's him stroking the pussy in the better Bond films, isn't it?

    2. RyokuMas

      Re: Meow.

      Nah, Bill hates cats...




      ... that's why he ran over Eadon's.

  9. mraak


    I have OSX and couple of Linux VM's, never once did I need an alternative to CTRL ALT DEL, and I don't even know what the alternative is, if there is one. I'm talking 4+ years now.

    1. ThomH

      Re: Interesting

      I've been on OS X for almost a decade now — I feel like I've probably seen that grey screen that tells you that you need to restart the computer three or four times. I guess that's the same as NT's blue screen, which I saw with about the same frequency before I switched to the Mac.

    2. Frankee Llonnygog

      Re: Interesting

      Llonygog's law: the only time you ever need anything is right after you say you've never needed it.

      On OSX, ctrl + eject brings up a logout/sleep/restart dialog

  10. Antony Riley

    Sun Server Keyboard...

    ...had a dedicated button for power down.

    It was the bane of my life.

    So much so we resorted to physical removal from the keyboard (yes I know there were 'soft' solutions, but the physical removal made us feel better).

    1. Antony Riley

      Re: Sun Server Keyboard...

      Some 8 bit computers had their own three finger salutes, I remember the Amstrad CPC used ctrl + shift + escape.

      1. graeme leggett Silver badge

        Re: Sun Server Keyboard...

        And the Amiga had one too - <Ctrl>-<Left-Amiga>-<Right-Amiga>; which since it could just about be done with one hand (rather than two as with Ctrl+Alt+Del) had a nickname of "Vulcan death grip" (or similar - it's been a long while since I put my Miggy away in the loft)

        Perhaps if Gate's single button had been under one of those covers you get for switches on military kit, it would have been more popular - harder to knock by accident and with a certain "hard-bitten" look.

        1. rurwin

          Re: Sun Server Keyboard...

          I always use one hand for Ctrl-Alt-Del.

          Thumb on Right-Alt, first finger on Right-Ctrl, second finger on Delete.

          1. Rattus Rattus

            Re: Sun Server Keyboard...


            I do much the same, except I find it more comfortable to turn my hand around the other way. This puts my pointer finger on right Alt, thumb on right Ctrl, and pinky on Del.

        2. Danny 4

          Re: Amiga reboot keys

          @graeme leggett

          "nickname of Vulcan death grip (or similar..."

          The Ctrl-Amiga-Amiga combination is also known as the Vulcan Nerve Pinch.

      2. Charles 9

        Re: Sun Server Keyboard...

        For the Apple IIe onward, Ctrl+Reset performed a break to the system prompt. Adding the OpenApple (the hollow Apple logo left of the Spacebar) performed a reset.

        The Commodore 64 and 128 had a Stop key. In BASIC, hitting this aborted execution; it mapped to ASCII 3 (Ctrl-C) so could be caught by any program (It was labeled Run/Stop because shifitng it ran the LOAD macro command for tape drives). On a harder note, holding it with the Restore key triggered a Panic sequence. It usually broke you out of whatever program you had, restored default colors and sent you back to BASIC. The 128 went the extra distance and added a hard reset button. To be on the safe side, though, it was located on the SIDE of the machine, next to the power switch.

        I believe the Atari 400/800 computer line had a dedicated reset button, too, located among a cluster of four normally above the numbers on the keyboard.

    2. Paul Crawford Silver badge

      Re: Sun Server Keyboard...

      But the Sun keyboards had support for a mouse coming out of them, which was long before USB hubs, etc, and such a neater arrangement. Also we had optical mice on our Sub machines of ~1992 which were cool, though they needed a gridded mouse pad.

      Shame that Sun screwed up so badly, and Oracle has done even worse :(

  11. Anonymous Coward

    Great Sense of humour, Bill!

    As has always been obvious in your company's software.

  12. Terry 6 Silver badge

    Single reset key!!!!!?????

    Blimey, most people I know struggle with just having the stupid cAPS LOCK NEXT TO THE A KEY.

    1. Dan 55 Silver badge

      Re: Single reset key!!!!!?????

      Tell me I'm not the only commentard who's read the article and understood that Gates wanted IBM to put a special logon key on their keyboards to be used by NT and couldn't get one so he went for a key combination instead? The fact it was the same key combination as the BIOS/DOS reset key combination does not mean that he originally wanted a special reset key for NT.

      1. Anonymous Coward
        Anonymous Coward

        Re: Single reset key!!!!!?????

        No, you're not the only one, although I was starting to wonder if I'd misunderstood...

        1. Allan George Dyer

          Re: Single reset key!!!!!?????

          There is some uncertainty, but I'd say you're wrong. In the video, Bill specifically references the guy that did the IBM keyboard, and also continues to say that they were doing interesting things, but in the software, like the extended character set with the suit characters. To me, this places the "one button" request when the original IBM PC was being designed. The alternative would be when OS/2 and PS/2 were designed, but the PS/2 keyboard is the old keyboard with a smaller connector, and the extended character set was part of the PC design too. Bill confused the issue by talking about the security reason for OS/2|NT login and then sliding into the hardware decision without making it clear the hardware was PC legacy.

          Either way, I don't understand why he thinks it was a mistake to make it difficult for you cat or s slip of the finger to loose all your work.

          1. Allan George Dyer

            Re: Single reset key!!!!!?????

            I meant to type "your cat or a slip of the finger to lose", but perhaps my subconscious was attempting irony.

    2. Anonymous Coward

      Re: cAPS lOCK kEY

      My first upgrade to any new Windows machine of my own was to disable that. It used to be a couple of lines in the registry: have they made it accessible yet?

      By the way, does anybody else get depressed when they see someone use the caps-lock key? Followed, probably by slow, single-fingered typing on a keyboard whose layout remains a mystery to them even after years of using it?

      I don't think I used the "Shift Lock" much even on a manual typewriter. At least it had to be pressed hard.

      1. Anonymous Coward
        Anonymous Coward

        Re: cAPS lOCK kEY

        4pEOPLE (aND cOUNTING) Like tHE cAPSLOCK kEY?

      2. Danny 4

        Re: cAPS lOCK kEY

        Don't know about Windows, but on Linux you can revert that useless and annoying Capslock key back into a Ctrl key (where the Ctrl key should normally be) by adding XKBOPTIONS="ctrl:nocaps" to /etc/default/keyboard.

        Or get a better keyboard like the HHKB that, along with the Windows keys, does away with it all together.

  13. Karlis 1

    Bill looks to be wrong here

    As far as I recall the C-A-D salute was actually feature of the original IBM AT design, special case being that it generated an actual _hardware_ interrupt from AT keyboard controller (the large, round 5 pin one) that would be handled regardless of the state of the rest of the system.

    When it was integrated into Windows (NT 3.5 first IIRC) it was actually for sound security reasons - that is, that the corresponding HW interrupt couldn't be faked by malicious software, therefore C-A-D would always be a safe way for operating system to get to a good known state (whether it was login screen (credential snooping) or task manager (fake one masking the malicious process) irrespective of any software trying to intercept it above kernel level.

    As far as I'm concerned that was an inspired hack on reusing something you wouldn't want to happen (random reboots from keyboard inputs) into something you would very much want to happen (fairly secure way to ensure that your login prompt is actually the login prompt, not a patched up worm).

  14. PassiveSmoking

    Didn't see the funny side

    Of course he didn't, it's an immutable fact that the man has no sense of humour. If you don't believe me, just watch those stupid Seinfeld ads.

    Or any clip where he's the butt of somebody's joke.

  15. Admiral Grace Hopper

    Three-Fingered Salute

    Or "The Windows Salute".

    1. Anonymous Coward

      Re: The Windows Salute

      Inherited from DOS.

      And deeply engrained in our psyche. On my LInux system, it does not, of course, reboot the system, but it does "reboot" the session.

      1. Admiral Grace Hopper
        Thumb Up

        Re: The Windows Salute

        Always pleased to be educated. I missed out on DOS except as the support player for Win 3.11 which is where I first encountered the IBM PC compatible, swiftly moving onto NT 3.51 which is where I first raised three fingers in anger. Prior to that, resetting the machines I worked on was done by an acolyte of the mainframe in the computer hall who would have to key the box physically. Simpler times that sometimes I sigh for. Wrangling Linux boxes gives me some of the same pleasures, but it's not quite the same some how.

  16. Jolyon Smith

    Kingston Reset

    I was once told that it was known within IBM as a "Kingston Reset". Anyone able to confirm or explain ?

  17. Anonymous Coward
    Anonymous Coward

    Bill Gates Knows Nothing About Computers (and lots about business)

    Gates: "So we could have had a single button, but the guy who did the IBM keyboard design didn't want to give us our single button,"

    "IBM engineer David Bradley designed the ctrl-alt-del shortcut, although the third key was originally intended to be esc rather than del. He used the three-key combination so the command could not be executed by accident."

    There you have the design skills of Bill Gates in a nutshell. Can you imagine the havok caused if resetting the computer had been a single button press? What an idiot.

    1. Anonymous Coward
      Anonymous Coward

      Re: Bill Gates Knows Nothing About Computers (and lots about business)

      @Robert: If you're going to throw around insults like "Bill Gates knowns nothing about computers" which is obviously complete rubbish, you'd probably want to educate yourself first:

      Bill wanted a single logon button on the new AT keyboard. Not a reset button.

      The IBM guy didn't really want to do that as he had lots of other stuff to be dealing with, so existing keys were used to generate to the same effect, by necessity this was CAD.

  18. Tony Green

    I don't think it was a mistake at all

    Had it been a single key it would have been all too easy to hit it by mistake and reboot your computer. The great thing about Ctrl-Alt-Del is that you have to REALLY mean to do it.

    Very much in the same way that 999 was chosen as the emergency number - in the days of loop/disconnect dialling the chances of any random line conditions, even on a seriously faulty pair, accidentally generating three nines in succession was extremely low. Had it been 111 there would have been lots of false calls by accident.

  19. Anonymous Coward
    Anonymous Coward

    "He used the three-key combination so the reboot could not be trigger by accident."

    Microsoft had that covered though; there would have been at least one, two or three warning messages seeking confirmation. I can just see Clippy now; it looks like you want to reboot. The most ironic part would be that the warning message would never appear as the OS is hosed.

    In reality though, there has always been a button that would "reboot" the computer; the power button.

  20. JustWondering

    "Made it famous"

    More like made it necessary.

  21. Bladeforce

    Makes me laugh people saying there was always a reset button anyway! Remember the days when pressing reset while windows was running would make you shiver because you just knew your chances of it not booting again jumped 80% lol

    1. david 12 Silver badge

      reset while windows was running ...

      Not at all like a reset of Novell (which could get you fired) or a reset of SunOS (which I've seen reduce a grown man to tears).

      1. Paul Crawford Silver badge

        Re: reset while windows was running ...

        Oh the joys of non-journalling file systems!

        1. Nick Ryan Silver badge

          Re: reset while windows was running ...

          I'm still waiting for a fully journalled version of NTFS...

          1. Anonymous Coward
            Anonymous Coward

            Re: reset while windows was running ...

            You're still running NT4?

  22. codeusirae

    <ctrl><alt><del> was a mistake?

    "So we could have had a single button, but the guy who did the IBM keyboard design didn't want to give us our single button,"

    "So what we had, we programmed at a low level. It was a mistake."

    I don't recall ever hearing this, does anyone else apart from Gates recall a dialog over the 'single button' issue?

  23. John Tserkezis

    I pretty much grew up with DOS, and have alt-ctrl-del so far engrained in my head I use it more out of instinct.

    Even on linux boxes when I'm not really paying attention - it shut down gracefully.

    I wonder if Microsoft managed to patent a sequence of keys?

    1. Anonymous Coward
      Anonymous Coward

      Ahh the days of PC cases with a reset button. I miss those days. Remember the late 80s/early 90s boxes with "TURBO" buttons on the cases? You always had large power button, small reset button and a "turbo" butting that made an orange LED come on.

      1. Anonymous Coward
        Anonymous Coward

        Once found (in a bargain bucket at a Game or similar store) a pre-owned games console controller with a "TUBRO" button.

        1. Lamont Cranston

          TURBO on a joypad?

          Most likely that's an autofire. Often found alongside the Slo-Mo switch, which would repeatedly pause the game (I never did work out how that would be useful).

          1. Charles 9

            Re: TURBO on a joypad?

            They called it a Turbo-fire to distinguish the fact the Rapid fire only happened as long as you held down the button, in contrast to a true auto-fire which simply kept that button rapid-firing with no user input.

            As for slo-mo, I believe this was intended as a way to help slow down fast-paced games making them easier to negotiate (more time to dodge bullets and so on). It was a bodge at best since Slow was basically Auto-fire rigged to the Start button (which since the Nintendo days was traditionally used to pause the game).

      2. Anonymous Coward
        Anonymous Coward

        Talking about the turbo button:

      3. Anonymous Coward
        Anonymous Coward

        Re: the days of PC cases with a reset button.

        They are still alive and well. I have never had a PC without a reset button.

        in Linux it initiates a shutdown. In (I think?) any OS, when held for 5 seconds it does a powerdown. Even my tower does this (why wouldn't I just hit the off switch? Not sure) but on laptops, where even the power "switch" is just another key, it saves pulling the plug and taking the battery out.

  24. Anonymous Coward
    Anonymous Coward

    Plus ca change...

    "Anyone with a passing knowledge of PCs will remember hammering those three keys to forcefully reboot the computer as code locked up".

    Yes - last week.

  25. Marvin O'Gravel Balloon Face

    As I remember things went something like this.

    1. Program Locks Up.

    2. You hit CTRL+ALT+DEL - NOT to reboot, but to display the "End Program" dialogue box.

    3. Nothing happens.

    4. In frustration you hit the same three keys again, just in time to see the words "WARNING: Pressing CTRL + ALT + DEL again will reboot your computer" flash before your eyes.

    5. Computer reboots, you lose all your work.

    1. Anonymous Coward
      Anonymous Coward

      Not under the NT series of Windows OSes, that was the 95 onwards, IIRC.

  26. Mostor Astrakan

    The cynic in me suggests that they co-opted the reboot key sequence so that people would get used to it and press it on more enlightened operating systems.

    1. Anonymous Coward
      Anonymous Coward

      That's so far beyond cynical and into paranoid conspiracy theory that you should probably seek help.

  27. Armando 123
    Big Brother

    Missing a key point

    " Harvard Campaign, a fundraising drive designed to raise $6.5bn for the Ivy League university"

    Harvard is the best funded academic institution in the world, sitting on hundreds of billions, enough cash to fund a third world nation for decades or to buy a US Senator for two weeks. The last thing this world needs is more money to go to the one institution who sends people to Wall Street, the US government, and Hollywood.

    1. Don Jefe

      Re: Missing a key point

      Colleges in the US are a business first and institution of higher education second. Even in the Ivy. It sucks.

  28. stu 4


    Bill Gates always reminds me of Kermit the Frog.

    is it just me ?

    1. Blane Bramble
      Thumb Up

      Re: Kermit

      Not just you, I've been saying it for years.

  29. Anonymous Coward
    Anonymous Coward

    And The Worst Keystroke Choice of All Time

    Goes to Informix --- for the ESC key executing the form you just filled in. What possible logic could there be behind Escape to actually do something?

  30. Anonymous Coward

    Bill Gates Admits WINDOWS Was A Mistake

    ...I can dream, can't I?

  31. Anonymous Coward
    Anonymous Coward

    The Ratner Effect

    Bill Gates admitting to wanting a reboot key on the keyboard is like Gerald Ratner bragging about why his jewellery empire was so successful. Correct in both instances. I only help Gates' blurt has the same effect to MS that Ratner's had to... Ratners.

  32. Tufty Squirrel

    *Some* people?

    >> Some people even called the shortcut a three-fingered salute.

    Not "some people", it was /everyone/. Everyone called it that. Everyone. Even people like me, who didn't use DOS or Windows, called it that. Because everyone knew what it meant.

  33. Dave Bell

    The reasoning behind the choice of Ctrl-Alt-Del to reboot the system is pretty good.

    All it does now is call up a special menu screen, and for that it may be excessive. So why did Microsoft adopt Ctrl-Alt-Del for that particular purpose? Calling up Task Manager isn't a bad option in modern Windows, not so wildly different from a reboot, but it's a longer, more complicated, process. The need for the original protections has faded. It's no longer a single step that you don't want to accidentally trigger.

    But either Bill Gates was being silly, all those years ago, or somehow it's been misunderstood just which part of the history he was referring to. The original Ctrl-Alt-Del is different from today's. Which is the mistake?

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