Difference between Docker and Virtual Machine
Anyone who used virtual machines (VMs) and Docker containers knows that Docker images tend to be much smaller than VM images and to start orders of magnitude faster. But why […]
Hacker’s diary
Redis demystified
Disclaimer: this is a summary for my records after a deep dive into current state of Redis. I tried to be as precise as possible (after all, I am writing […]
Redis: hset with ‘items’ parameter
In Python, Redis.hset function has ‘items’ that, per documentation “accepts a list of key/value pairs that will be added to hash “name“.”. You would think that it’s something like [(“key1”, […]
Writing unit tests with Cursor IDE
I created a “view model” like hook in React, and asked Cursor to write unit tests for it. The hook does not have any HTML code, but it uses a […]
Lenovo windows “recovery” media and other animals
TL;DR: Lenovo recovery media is NOT like regular Windows recovery drive. It can only factory-reset your system. No command line, no recovery from image, nothing else. Hulk smash. Don’t count […]
Apache mod_wsgi: demystifying WSGIApplicationGroup
Summary WSGIApplicationGroup is a name of the Python sub-interpreter. You don’t need sub-interpreters if you run mod_wsgi in daemon mode (i.e. with dedicated processes). Always set WSGIApplicationGroup to %{GLOBAL}. If […]
Chrome: thisisunsafe!
TL;DR Under certain circumstances you won’t be able to access an HTTPS site with invalid certificate from Chrome, unless you type a magic cheat code “thisisunsafe“. I was debugging a […]
C++ random number generation: mt19937 to ranlux24
It’s pretty old stuff, but still… Here’s how you typically generate a random number in C++: Let’s dissect it a little. On the one hand, “random_device” is a rather nebulous […]
Python: the land of abstract static methods
Summary Unlike many other languages, Python allows abstract static methods (see the reference). A class directly or indirectly deriving from abc.ABC cannot be instantiated, unless all its abstract methods are […]
Are Python strings UTF-8? What is the complexity of s[n]?
![Are Python strings UTF-8? What is the complexity of s[n]?](https://ikriv.com/blog/wp-content/uploads/2025/03/string_encoding_comparison.png)
TL;DR Internally CPython stores strings with fixed character size of 1, 2, or 4 bytes, depending on the string [PEP-393]. The indexing operator s[n] takes constant time. UTF-8 representation can […]