Every time we have a story like this, every time I ask - how does this work on a blockchain? Many people will talk about blockchain trustless-ness and how this doesn't requires trust etc. And I ask give me an end to end example of what are the trust issues here and how does blockchain solve it? I have yet to get a concrete answer.

So, again what trust issues does blockchain solve?

To ensure we are not talking about completely abstract things let's take a real life example. Here's an issue:

https://www.reuters.com/article/us-welspun-india-walmart-idU...

Wal-Mart Stores Inc on Friday said it will stop selling Egyptian cotton sheets made by Welspun India after the Indian manufacturer was unable to assure them the products were authentic.

How does blockchain help?

Everyone is claiming this could be done with a database but no one knows all the details because the article is literally three sentences long.

The article states this initiative "helps reduce waste, better manage contamination cases and improve transparency"

This is how I envision this system working. I think the fact this is produce and not normal inventory is key.

Produce is produced by farmers, transported by shipping companies, stored in warehouses, and eventually ends up on a shelf after a long chain of custody.

Reducing waste and contamination sounds like a tracking system. So every food item gets an ID and as it moves through the system it gets logged with time, location, and so on. Pretty standard, and yes, totally doable with a database.

But this project also helps to improve transparency. Transparency to who?

The previous actors in our example. The farmer, the shipper, storage, maybe inspectors.

They have no inherit reason to trust each other. The last shipping company will blame the warehouse for the moldy food. The warehouse will blame the farmer. The inspectors said they approved of it but obviously its gone bad.

Maybe the 6 days to track this produce before wasn't really in tracking it, but dealing with the human element of the chain of custody. Two minutes to pull up a verified log of events.

I am a regular and boistrous cheerleader for the prospects of blockchain technologies to empower changes in the world... but I do not understand what is going on here.

This seems entirely centralized, and thus a very poor use case for a blockchain.

There's no such thing as "the" Blockchain. Walmart is using "a" Blockchain, in which I'm guessing they themselves own and operate all nodes.

> Yiannas said blockchain was able to cut the time it took to track produce to two seconds from six days.

With no more detail I can't even start to think how a Blockchain DB makes any difference?

I guess they didn't try with a "signed append-only log", they might be able to shave off even these two remaining seconds.

Either I have greatly misunderstood the purpose of a blockchain, or they have... I'd love to see them add some details around how the blockchain actually saved them time and why a standard database of some kind wouldn't suffice.

I can see where this might be good for some sort of accreditation, although there are other ways of achieving this. But this allows walmart to say "our product comes from XYZ" and independent parties can verify that.

This blockchain uses IBM's blockchain technology, which is in turn created with Hyperledger. In both cases, the technology is called enterprise grade. That seems to be true - though, I'm not sure a blockchain is needed here. Maybe a ledger with distributed access, but not necessarily a blockchain.

https://www.ibm.com/blockchain/platform/

https://www.hyperledger.org/about

The Hyperledger Fabric, which IBM is using, is explained here: https://www.hyperledger.org/projects/fabric

There is a video that offers a high level view of farm to fork (agriculture products to consumers) using the block chain ideas in Hyperledger Fabric.

From Nigel Gopie, an IBM Food Trust speaker, says "The permissioned blockchains we rely upon (hyperledger fabric) don’t use don't use proof-of-work or "mining" — unlike some other Blockchains like bitcoin — which is what consumes huge amounts of energy. " (from a tweet conversation after a presentation he gave in Denver April 2018: https://twitter.com/analyticsbytes/status/984140954834632704)

Replace "Blockchain" with "Database" and it would all be true.

Walmart Inc. is getting suppliers to put food on the [database] to help reduce waste, better manage contamination cases and improve transparency.

Yiannas said [database] was able to cut the time it took to track produce to two seconds from six days.

Blockchain is the new NoSQL. In 10 years some poor engineer tasked with maintaining this thing is going to ask why they didn't use a more reasonable technology.

Is a blockchain even required for this? Does it provide any technical advantage here in this case?

> Walmart Inc. is getting suppliers to put food on the blockchain

Phew! Blockchain is NOT a database, you don't put something ON blockchain. Blockchain is meant to track changes of data, not store the data. The size of the entire Bitcoin Blockchain over the last 9+ years is 194.86GB [0] i.e. it can be stored on your local hard drive. Therefore, you can't put "food on blockchain".

[0] https://bitinfocharts.com

This just in!

Amazon to stop delivering goods by walking to people's front doors, now delivering through the radio waves!

I eagerly expect the converse product: Blockchain enabled sanitation systems, that would allow one to relieve themselves on the Blockchain.

That's a billion dollar ICO right there.

Is the article partially behind a pay wall?