This article explains the Linux kernel bitmap data structure, its definition, macro-based declarations, related assembly instructions, core bitmap APIs such as set_bit and test_bit, various bit‑operation functions, and practical applications ranging from PID allocation to device management and file‑system indexing.
This article explains how to use Redis Bitmap to efficiently store and query massive binary‑state data such as user login status and daily sign‑in records, covering underlying memory structures, command usage, and practical examples for counting, checking, and aggregating large‑scale user activity.
This article explains how to use Redis Bitmap for binary state statistics such as user login status and daily sign‑in tracking, demonstrating memory‑efficient storage, relevant commands, and techniques for counting continuous sign‑ins across massive user bases.
This article introduces Redis's advanced bitmap capabilities, detailing the SETBIT, GETBIT, BITCOUNT, and BITOP commands, their syntax, underlying SDS data structure, performance characteristics, storage calculations, and practical use cases such as user sign‑in tracking and online status monitoring.
This tutorial explains Java's signed two's complement representation, demonstrates how to output binary strings, covers all bitwise operators (AND, OR, XOR, NOT, shifts), clarifies original/one's/complement forms, shows overflow handling, unsigned tricks with masking, and teaches packing multiple boolean flags into a single byte for efficient storage.
This article explains how to use Redis bit operations and bitmap keys to record daily user logins and efficiently compute statistics such as today’s active users, users active over the past three days, and users active within a week.
