Python Internals: How Python Works Under the Hood
Understanding Python's internals transforms you from a user of the language into someone who truly understands why things work (or don't). The reference counting garbage collector, the Global Interpreter Lock, object memory layout, and the distinction between CPython and the language specification all affect the code you write daily.
This collection covers what happens beneath the surface: CPython implementation details, memory management, the GIL and free threading, Cython for performance, and low-level data handling with byte streams and compression.
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CPython: The Default Python Implementation
What CPython is, how it differs from the Python language specification, and why it matters.
Cython: Write Python, Run C
Using Cython to compile Python to C for performance-critical code paths.
Python Memory Management
Reference counting, garbage collection, memory pools, and understanding Python's memory model.
Why Python Is Not Pass-by-Reference
Pass-by-object-reference explained, with examples showing how Python's calling convention works.
Python Immutability
How immutability is implemented, which types are immutable, and the effects on memory and hashing.
Why Does Python Have a GIL?
The design reasons behind the GIL, how it affects multithreading, and workarounds.
PEP 703: Free Threading and the End of the GIL
The free-threading proposal, what it changes, and the path to a GIL-free Python.
Python Runtime Services
The sys module, runtime configuration, and introspection tools for understanding program execution.
Python sys Module: System-Specific Parameters
Deep look at sys module functions for memory, recursion limits, and interpreter state.
sys.monitoring: Execution Event Monitoring
Python 3.12's sys.monitoring API for low-overhead execution tracing and profiling.
Understanding Big Endian in Python
Byte order, endianness, struct module, and handling binary data across platforms.
Understanding Byte Streams in Python
Working with bytes, bytearray, memoryview, and binary I/O in Python.
Python Compression Algorithms
zlib, gzip, bz2, lzma, and implementing custom compression with Python.