Why 1/1/1970 Bricks Your iPhone 

This video has a correction! Years after this was published, Civilisation creator Sid Meier made it clear that "Nuclear Gandhi" was just a myth: kotaku.com/civilization-creator-shoots-down-our-memories-of-a-nuke-1845006305 - for all corrections on this channel, see www.tomscott.com/corrections

"Ghandi was a dick" - Tom Scott

Don't you just hate when Gandhi gets a negative underflow and starts declaring war on everyone

When Gandhi gets a negative underflow: “Peace was never an option”

me: hey phone its currently 1970 phone: ok me: when did i call john again? phone: about 17 trillion years after the heat death of the universe me: oh

Plot twist: the universe was created in 1/1/1970

“War is good” -Gandhi Probably

The important thing to remember when doing time calculations in your code: don't do time calculations in your code, ever. Not even if forced at gunpoint. Use the provided libraries instead.

3:06 It was worse. Much, much worse. The normal maximum aggressiveness in the game was 10. The underflow bug put Gandhi's aggressiveness at 255 on a scale of 1 to 10. Way, way off the scale.

We're gonna party like it's 1969.

Clickbait, nothing about bricks

Fun fact: Discord references this on mobile when you join on ongoing call. The length of the call says 1/1/1970

I've known about the Gandhi bug for years and even checked it out, but it still gets me everytime that this peace-loving guy would start yeeting boom balls at people.

They caught the Nuclear Gandhi bug in playtesting but it was so funny they left it in. It literally changed the course of Civilization.

I did this and my phone turned into a brick, now i'm building iPhone houses.

Everybody going to ignore the attention to detail in this clip? He's sat telling us this in front of some ghastly 70's inspired wallpaper.

That 64-bit time visualization at the end really shows how catastrophic this kind of stuff actually is. Awesome stuff.

my moms old iphone 4 swears it is january 1968 every time you turn it off

to be honest, I hadn't ever considered interger underflow in my code. I never write anything particularly complex, but this is a nice reminder that things are not always simple. I have had to consider interger overflow before, but mostly because I accidentally wrote some code that had an overflow that would crash the software at random points in its run. spent weeks trying to figure it out before my dad of all people said "that calculation is going to return a number higher than 32 bit"

Interesting - I’m an Apple Technician, and we just switched to a new repair system, but we’re Kinda in a limbo in between both old and new because the new one is a big change. In the new one when we go to check somethings coverage sometimes it says “31/12/1969”. I don’t think there is any correlation but it’s interesting :) (We can still find coverage it’s just an extra step)

If I were a writer for Doctor Who, I could write an episode around this

Don’t you just hate it when you are in December 1969 and your iPhone is in 21 trillion

Apple really doesn’t want us to have our phones on 19 funny number

No one: RU-vid for some reason: I think you are going to enjoy this after 5 ****ing years since this video is published

Nobody: Ghandi: "Peace is the question and the atomic bomb is the answer"

*Why is this video from 1970 getting recommended to me in 2019* Edit: after clicking on this video 71 times to read my notifications I think I might watch the video

Instructions Unclear, thew a brick at my Iphone

Going back to this video ~5 years later, I get to smile to myself that I understood the words at the beginning of the video. It isn’t much, but it’s definitely a reminder that I’ve made progress in understanding something I’m as passionate as I am about. Thanks for that. :)

I did it and someone threw a brick at my phone.

Man, this is like a horror story.

"Gandhi started declaring war on everyone" -Tom Scott 2016.

Imagine going into a time machine excited to meet every famous person from history just to find out that it's computer unit has this exact same bug and you end up at the location of time during the heat death of the universe.

I still don’t understand the awkward and uncomfortable camera scene change

*Who was also here just to learn how to birck everyones iPhone but instead learned about how to get Ghandi to delcare war on everyone*

"And if you understand those terms, you don't need this video" Well Imma still buckle up

happened to me in discord when I'm glitched in a call it says 1/1/1970

Am I only one who "doesn't need this video" yet still watches?

"well this would be called an 'integer underflow'" Me: he's gonna talk about the Ghandi thing

I would definitely have you as my teacher you explain everything so clearly

1/1/1980 is also another common start date; When on Windows 3.1 in the year 2000, it went back to 1980 creating havoc with when I last saved my files!

Plot Twist: We're in the matrix and it was created in 1/1/1970

to the apple store to brick the display model!

I know what an 'integer underflow caused by the Unix epoch' means but I love watching Tom talk about tech

"Timezones and irritating human things like that" Timezones are truly irritating -from a person in a long distance relationship

Now i know why Gandhi was such a war monger lol Fascinating bug, great video!

Is it just me who is really tempted to set the date to 1/1/1970 now

The fact youtube didn't set the date this video was uploaded to 1/1/1970 makes me sad

The thing that always gets me about coding is how the most minute detail perpetuates towards something catastrophic. Fascinating video. Thank you!

One slight correction; The Civ 1 bug. The AI was coded using several traits each on a scale of 1 to 10, in the case their aggression, as an 8bit integer. Ghandi starts the game with a value of 1, represented as simply 00000001 in 8bit. However later when the tech diplomacy becomes availible, this tech is interesting as it drops all the AI's aggresion by 2, resulting in Ghandi having an aggresion of 11111111, or 255 out of the maximum of 10. Ghandi doesn't go from the lowest to the max value. He goes from the lowest value to over 25 times the max value.

That's an epoch fail!

There was an underflow glitch in the original _Sonic the Hedgehog_ on the Mega Drive. In the Final Zone, the boss took eight hits to kill, but it was possible to hit him twice on the last cycle - doing so would underflow the counter to -1... aka 255. Good luck getting another 255 hits before the time ran out!

I came back here a few years later and i finally understand the "interger underflow in the unix epoch" :D

Why would someone change their date to 1970? They think they're going to time travel or what?

So now we're in the year 46 U.E. (Unix Era)?

"Ghandi started declaring war on everyone" is a sentence that came out of a man's mouth

Although I already knew what UNIX Epoch was, I kept watching the video anyway because you do such a good job explaining it.

Google tells me that one of my devices has been registered on 31. dec 1969... Does it mean I got a phone from the past or the future?

The Doctor: Sets the Tardis to January 1, 1970 Tardis, running on Linux: End of the universe? You got it, boss

Don't usually watch this type of video but this lad is well easy to watch, short and sweet, with quick clear info 👍

This guy could probably explain rocket science to me in an understanding way

When forced to give my date of birth on websites I always use 01-01-1970 :)

"If you understand those terms, then you don't need this video." My ability to speak doesn't make me intelligent.

4 years on and I still keep trying to scrape that little black dot on the wall behind you off my screen...

And here I am now, 7 years later and about to finish my Computer Science Major, with Tom Scott being the one who originally taught me what an Integer underflow is when I was still in school.

"using 4 binary digits, you cant count higher than 15" okay, im following you... "with 64 binary digits, you get a number 20 times the length of the universe." ...

this person: setting your date to this will render your phone inoperable. it will break your phone and make it stop working. me, a person who uses my phone a lot and wouldn’t be able to afford a replacement/repair, before even clicking on the video: i wanna try it

It’s been 4 years. This still ticks me off as of today

Liked specifically for that intro about the Linux time. *Chef's kiss* loved the delivery

I wonder how many people here who knew the terms listed in the reason _actually_ left instead of watching the video.

Instructions unclear.. Now my iPhone is backed with nuclear weapons..

I have a generation 2 iPod. Every time I check the date/time on it, it shows 1/1/1970. Even if I change it to today, it always ends up reverting, making the time on the display inaccurate. This video explains a lot, a guess that the internal clock is bugged so that it keeps resetting.

Some of the pictures in my phone have the date set to 1/1/70 for some reason. I think the metadata was corrupted in some way.

That number check is probably the indicator "Last time backed up xxx hours/days ago" under iCloud.

I feel like I accidentally walked into the extended mathematics degree class mid-lecture and somehow got mentally lost and now I cant remember what I was gonna do

This was happening in the mini iPad we got in 2011. I haven’t used it regularly in a long time, but when I turn it on, most times the date says December 31, 1969. Then it sometimes switched to the actual date. I haven’t checked it in a while, and I know it would also display the 1/1/1970 date too

Your videos never cease to entertain me.

I did understand those words, but watched the video anyway.

Stop apearing in my recomended. I watched one video and now i keep getting your videos in my recomended. Im getting smarter. This is bad

I understood the terms but kept watching because your style is so engaging

I remember in school, setting the time and date about half an hour before the maximum date time, then wait for the computer to crash when one of your mates was using it 😂 only when it wasn't super important stuff that needed saving though, just a bit of fun 😀

they fixed it cause you can only go back to december 31st, 2000 now

Why do they even let us set the date back?

That wallpaper has bricked my eyes

So like did everybody just get this recommended

if apple ever confirmed the bug they would explain it in vague hipster terms and call it something catchy like iFuckedup

You could make a video on why doors open and I'd still watch it

This is interesting! I had this bug today on discord. It said that the call was running since 1970. Know I know why

Could it be that time till last full charge is stored as an epoch of the time difference. When the OS checks the epoch time till last charge and tries to take it away from the current epoch to display it in the settings it goes before 1/1/70 and you get your error

Steam: (some game) last played 01.01.1970 me: oh ok

Comments under this video: 1% Stuff that actually makes sense. 9% Stuff loosely relating somehow to 01/01/1970 90% Ghandi declaring war

0:13 me *understands* also me : " i still very much need"

I knew the words, but i still needed the video... What i learned was: Fail-safe your system from accidentally causing underflows, by simply making sure to always have a querry and an exception throw catch handler which will do a stack trace and log it in a dump. Very usefull.

just checked: an iphone 7 running iOS version 10.0.1 won't even go as far back as 2003. Update: it actually skipped back to 2001 Jan, 1st. then my internet cut off a few minutes later. my google chrome browser claimed the certificate for the server was not authentic and was 5735 days in the future. after i switch the time back everything resumed to normal.

Very late but, for those wondering: Why 1970? Because the people who designed UNIX chose it. There's no special reason. Why "bricked"? Because if you set the clock to 1970-1-1 and restart the phone, it won't start up anymore, making it about as useful as a brick. (I'm sure it's been fixed by now though.) Why no negative numbers? Because in a computer you only have '0' and '1'. You don't have '-'. You can tell your program to interpret one of those digits as meaning positive or negative instead of being part of the actual number, but they didn't bother to do that here. Why does this prevent the phone from starting up? No idea. Some code doesn't handle this situation correctly and does something wrong.

There's a similar example in Lufia II, except the other way around. In this game, there's a superboss (The Egg Dragon) that have very high HP (and stats). So high in fact that if you heal his HP (with a potion for example), they will roll back to zero and become approximately equal to the damage healed, which makes it super easy to beat in one hit

This explains why, if you're a broadband tech support agent in the UK, and there's a major service outage... A lot of the time Openreach will say the service outage has been going since the 1/1/1970. It must struggle to find the real start date and just give the earliest possible date it can.

"Gandhi was a dick" - British person

why the heck do they even let you set the date to 1970 , is it in case you travel back in time or something?

1:18 I too still use a Dell Precision M4800 laptop to this day

"And ghandi started to declare war on everyone" had me laughing so hard