How Minecraft's Most Over-Powered Dupe Glitch Got Patched

This is how the infamous Minecraft duplication glitch ended up getting patched. It was more complicated than you thought.

[JackMasterOfNone]

i feel these kinds of videos are important to the history of gaming, just having logs like these of obscure happenings.

[DeaDnox]

*Read the title*
" Patched "
*Cry*

[nk]

“The WiFi password is on the back of the router”
Back of the router: 1:11

[hitchman]

This dupe glitch is mostly my fault. When I wrote the new save format (McRegion) in January 2011, chunks were much smaller, and I didn't imagine one being larger than 1MB after compression, so I stored chunk size as an 8-bit quantity representing the number of 4KB chunks. Anything larger would be *silently* discarded. This wasn't very easy to hit until custom books were introduced in 2012. Mojang's bugfix stores huge chunks in their own files.

The offending code:
protected synchronized void write(int x, int z, byte[] data, int length) {
int sectorsNeeded = (length + CHUNK_HEADER_SIZE) / 4096 + 1;
if (sectorsNeeded >= 256) return; // maximum chunk size is 1MB

[RunicCs_]

Book duping was a blessing and a curse.

[Mauricio]

Imagine if a dupe like this would exist in the nether update. Everyone would be full netherite in one hour.

[ysbsjdr]

Imagine a dupe being so powerful, mojang themselves needs to patch it.

[thebruheternal]

3:02 "Purchase an unban"
Lmfao

[lfricmunuc]

3:57
So there is Nazi gold buried in the antarctic!
I knew it.

[Scrotes]

Duplicating in Minecraft is like Rust. There's always more... You get rid of one...two more pop up to take its place.
Duping is not just an exploit. It is a religion.
Y O U - C A N N O T - H I D E - F R O M - U S .

[comedyman]

You can't just say you crashed an economy and leave it at that! What happened afterwards to the server you Mansa Musa'd?

Funfact: The "you can't write books" "fix" actually just prevented you from right clicking while holding a book and quill, or rather ignored the event.

Calling the right click action from code worked though, so that's why you still were able to write them using your bot.

[Weisz]

Sick video dude - perfect to watch while I’m overnight auto-fish farming on my buddy’s minecraft server

[BirdDoesThings]

uh- 10 minutes ago? i thought it said 10 months ago- oops.

[joshhorrocks]

Java: Fixes biggest duping glitch
Bedrock: *Allow me to introduce myself*

[shrekpaidaisuki]

2:28 I recognize that blur you used, see you soon

[MrBlockoh]

I really love the mine craft music in the back

[trippinonza]

Salc1: uploads video
20 secs later
everyone: wow great vid

[ysbsjdr]

You should've just hid the dupe items on random locations, that way you can have op stuff on all of the popular servers haha.

[rhythmcompany]

I like how this man could easily topple entire economies and become the leader of trading and what-not, yet he chooses to distribute the wealth and create a better world. Amazing.