CODEX

A mysterious algorithm from Atari 2600 to Commodore 64

Thanks to a random Twitter list I have found an interesting paper and I have become aware of the existence of a field of research called Archeogaming which uses the approaches and the methodology coming from archeology, historiography, and software engineering to dissect and analyze the design and the implementation of ancient video games.

The paper is Entombed: An archaeological examination of an Atari 2600 game and is a first, successful (in my opinion) attempt to formalize the Archeogaming field of research.

The paper is really interesting and it is fun to read and, as the title suggests, it provides…


Here we will shortly discuss how the msg.sender mechanism works. As usual we will experiment with small chunks of Solidity that you will be able to run in your browser

At the core of the blockchain is the mechanism of adding blocks of transactions to the chain of blocks: this is the job carried out by the miners that keep the state of the Ethereum Virtual Machine (EVM) consistent; miners are in a competition to append transactions to blocks.

The state of the EVM is the effect of the execution of all the transactions collected in blocks: in a way…


Reality is complex: please note that in the previous sentence complex has a very specific meaning; let’s just investigate a little more about it.

Photo by H Shaw on Unsplash

Complexity

Complexity theory has been inspired by some famous problems that come to the attention of the scientific community in the final decades of ‘800. One famous instance of such a family of problems is the Three-body problem: let pick three bodies in space (planets, satellites, etc…); we know that they are subject to the gravitational laws; to simplify things let consider them far away from each other object, so we can suppose that gravitational laws are…


A look at the SafeMath library from OpenZeppelin

Crystals
Crystals
Photo by Michael Dziedzic on Unsplash.

In Solidity, there are plenty of different alternatives to things you take for granted in other languages. Strings and math are two examples.

“Arithmetic operations in Solidity wrap on overflow. This can easily result in bugs, because programmers usually assume that an overflow raises an error, which is the standard behavior in high level programming languages. `SafeMath` restores this intuition by reverting the transaction when an operation overflows.

Using this library instead of the unchecked operations eliminates an entire class of bugs, so it’s recommended to use it always.” — OpenZeppelin docs

“Operations in Solidity wrap on overflow” refers to…


Getting started with Solidity

The word “WORLD” spelled in LED lights in a dark room.
The word “WORLD” spelled in LED lights in a dark room.
Photo by Martim Braz on Unsplash.

Strings of characters represent the very heart of every programming language because, you know, computers often interact with humans. For this reason, handling strings is one of the first functionalities developed in any language. Furthermore, the first test traditionally prints the string “Hello, world!”

Solidity is not an exception. It has native support for strings, but still, their use is not complete like in high-level languages such as JavaScript, Python, or Java. For instance, out of the box, Solidity does not offer a native way of comparing or concatenating strings. However, the documentation offers a valid solution for both functions…


How ‘selfdestruct’ works in Solidity and how it affects the life of the freshly self-destructed smart contract

Photo by Harrison Kugler on Unsplash

For the purpose of this article, I have read some good sources, starting with “Why Do Smart Contracts Self-Destruct? Investigating the Selfdestruct Function on Ethereum,” a recent publication that really digs into self-destruct mechanisms. The selfdestruct command stands out in the general immutability of the blockchain: selfdestruct renders inoperable a smart contract. A motivating example of why an immutable blockchain needs such a powerful command is reported in this paper:

“The DAO attack continued for several days and the organization even noticed that their contract had been attacked at that time. However, they could not stop the attack or transfer…


In this short tutorial I will try to summarize few simple steps to configure Logstash to emit data to Azure Event Hubs Before starting just few words to describe the two components we will work on:

“brown tree log lot” by Dimitri Tyan on Unsplash

Logstash — it’s a data processing pipeline that ingests, as rapidly as it can, data from a multitude of sources simultaneously, (slightly) transforms it, and then sends it to your favorite “stash”. It is designed to read logs, wherever they are hosted, and send them over, as fast it is possible, to the broker that will memorize, manipulate, display them. The general advice is…


My current job is in a large company with a lot of different business: it’s a bank, a national postal service, a large insurance company, it even has airplanes and a huge logistic network.

By Mike Beauregard from Nunavut, Canada (Stripes) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons

Giving in a single glimpse into the IT infrastructure of the company is like looking at sedimentary rocks: the result of tens of years of deposition of the remains of design decisions that have been cutting edge when they have been took and that nobody cared to actually remove when they were not anymore efficient or effective.

In this short post I will summarize what I’ve…

Rosario De Chiara

Data Masseur, Distributed Systems Sculptor, and Scalability Evangelist

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