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I couldn't find the answer specifically on this issue, if it is. Most are on how to turn it off/on.

What is the purpose behind having the num lock key off during startup?

Is it impossible to boot with it on?

It's a trivial questions I know.

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closed as not constructive by Ƭᴇcʜιᴇ007, Nifle, Dave M, Canadian Luke, kmarsh Feb 13 '13 at 22:28

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.If this question can be reworded to fit the rules in the help center, please edit the question.

Definitely trivia. And even got a technical answer. Yay! – vonbrand Feb 13 '13 at 2:45
I have heard that this is for security reasons, but never found specifics regarding this. Unfortunate that this was closed. – AaronLS Feb 10 '14 at 4:19

Is it impossible to boot with it on?

Normally, you can configure this in the BIOS. However, the operating system might change the NumLock state during startup.

In Windows, you can set the initial NumLock state by creating/modifying a registry key:

  1. Open the Registry Editor (Win + R, regedit, Enter).

  2. Go to the key HKEY_CURRENT_USER\Control Panel\Keyboard.

  3. Modify the value InitialKeyboardIndicators or create it if it doesn't exist (type REG_SZ).

  4. Set the value to 2 for NumLock on, 0 for off.

Source: InitialKeyboardIndicators

What is the purpose behind having the num lock key off during startup?

This may have historic reasons. When the NumLock key was invented, there were no other arrow keys on the keyboard, so defaulting it to off made sense.

Nowadays, it's a matter of personal preference. Some people (me included) could not live without the numeric keypad; other never use it. But since you can adjust the setting, it doesn't really matter to what it defaults.

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This is purely a preference thing - most modern systems should tolerate it either being on or off. Indeed, most systems have the default for this as a configuration option in the BIOS.

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No, this would be convention only. Some bioses (at least historically) even had the option to set this. As you can boot even without a keyboard (or a USB or PS2 keyboard if the PC supports it), it would be safe to assume that, technically its a trivial question.

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On desktops it is a matter of preference. Either you boot with num-lock on and use the numberpad, or you boot with num-lock off and use the cursors on it.

Since most 'modern' keyboards now come with a dedicated cursor and a 6 key PgUp/Down/Home/End/Del/Insert block the choice is no longer as important as it used to be.

On laptops it is a different story. Many laptops an internal keyboard with no numpad. Turning numpad on disables a lot of keys on those keyboards, and maps them to numbers.

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