Daniel Lemire's blog

We sometimes need to convert binary data to text.

Redis is an in-memory database.

Python used to have limited parallelism, due to its global interpreter lock (GIL).

WebSocket is a standard protocol to hook up a client and a server in a persistent manner.

When a Python program starts, it needs to load all its dependencies (import).

I write a lot about data parallelism.

When you build a program, the compiler turns each source file into an object file.

We have many ways to ensure software quality.

Much of my research is on arXiv.

Google’s first orbital data center is in orbit (October 1st).

A common way to store JSON data is to write one document per line.

Our software represents strings using the UTF-16 or the UTF-8 formats.

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The simdjson library is a C++ library to parse and generate JSON.

C# strings are UTF-16.

To get a PhD, you typically have to enroll in a graduate program.

We create new strings all the time.

Mainstream economists have been advocating for the marvellous effects of global trade for decades.

I maintain and comaintain several open-source libraries.

Our processors can execute many instructions per cycle; they are superscalar.

If AI is causing mass unemployment among software developers, it is not showing up in the data yet.

I see the mathematicians panicking at what we can do with agentic AI.

Recently, I looked at how AMD made its chips 50% faster within a span of two years, in How did AMD Ryzen get 50% faster in two years?

ARM processors, like those in your phone, have instructions capable of processing several elements at once (SIMD).

People still tell me that CPUs are boring.

C++23 added a new type to the standard library: std::flat_map.

We represent floating-point numbers using the IEEE standard.

Mathematicians are unhappy about OpenAI.

We are told that AI entities much like ChatGPT might soon kill us all.

If you write in C, by default, you use a single thread.

In the late 1960s and 1970s, people like David Parnas faced a problem.

In Python, the dict data structure is the conventional key-value structure.

JSON is a standard format for data interchange.

In Java, you find the location of a substring using indexOf.

We are all familiar with IP addresses such as 192.168.0.1.

Like most programming languages, Go has both stack allocations, whose lifetime is limited to the current function, and dynamic (or heap) allocations.

AI-assisted programming is fast evolving and there is a tension between ‘we no longer need to understand the code’ and ‘what is my purpose as a programmer’.

When a compiler optimizes your program, it has to guess.

C++26 adds a new container to the standard library: std::hive.

When your program asks for memory that is not in cache, the processor has to go to RAM.

Every week, I discuss with people who want to get a PhD.

In 1945, Vannevar Bush published a report entitled Science: The Endless Frontier.

A few years ago, a friend of mine was stuck.

I have been on X for a long time.

When I was a kid, most people did not know how to type.

Suppose that you have a configuration file in JSON.

The keyword in politics these days is ‘sovereign’.

Our 64-bit Intel and AMD processors have evolved over decades.

Where is your intelligence located?

Every machine connected to the Internet has an address called an IP address.