Rico's Nerd Cluster

「离开世界之前 一切都是过程」

Linux - Programming And Toolchain

ldd

ELF and Dynamic Linking Executable and Linkable Format (ELF) is the standard binary file format on Linux, most BSDs, and many embedded systems. It replaces older a.out and COFF formats. | Aspect ...

Linux - Filesystem

inode, soft/symbolic link, FIFO

Inode On every Unix-style filesystem (ext4, XFS, APFS, etc.), each regular file, directory, FIFO, … is represented on disk by a tiny metadata record called an inode (“index node”). That’s like a f...

Linux - Udev Rules, Systemd Services, inotify

Udev Rules Systemd Services, Inotify

Udev Unix Kernel is a monolithic kernel and provides API to access these hardware. Udev is a device manager of Linux Kernel, and serves as a successor of the Unix Kernel. It handles device nodes i...

Linux - SSH and X Window System

X Window System, SSH, Static IP

SSH Generate an SSH Key: ssh-keygen -t rsa -b 4096. This will create ~/.ssh/id_rsa and optionally sets a passphrase Copy ssh onto a remote machine: ssh-copy-id username@rem...

Electronics - General Science Facts

Adiabatic Cooling, Centripedal & Centrifugal Forces

Adiabatic Cooling In an adiabatic process, the system does not gain or lose heat (Q=0Q=0), meaning that all changes in internal energy come from work done by or on the gas. For an ideal gas, the i...

Literature - The Wealthy Barber Notes

Financial Literacy

Roy’s Story “We all felt bad about Roy having to put off his dream of becoming a lawyer, but deep down we knew that he was doing the right thing. You got to be there when your family needs you,...

Electronics - General Electronics Notes

Encoders, Motors, Capacitors, IMU, Testing, Telecommunication

Electronics EEPROM EEPROM (Electrically Erasable Programmable Read-Only Memory) is a type of non-volatile memory used in microcontrollers to store small amounts of data that must be preserved whe...

Electronics - Embedded Systems Notes

HAL

HAL vs SAL Hardware Abstraction Layer (HAL) is software that abstracts hardware-specific details from the application or higher-level software. It provides a unified API for accessing hardware fun...

Electronics - Communication Protocols

Encoding / Decoding, Error Checking (CRC), Base64, EtherCAT

Error Checking CRC GF(2) Math GF(2) is pronounced as “Galois Field 2”. Often used in cryptography, it’s a binary field that contains only 0 and 1 for error correction. Some properties of GF(2):...

Electronics - EMF and Eddy Current

Electromotive Force (EMF,电动势) In short, EMF is: 1 changing magnetic field -> induced voltage It’s characterized by the Faraday’s law: \[\begin{gather*} \begin{aligned} & \epsilon = -N \...