Oktal
100
Leitfaden zum Oktalsystem
Octal Number System
The octal system uses 8 digits: 0-7. Each octal digit represents exactly 3 binary bits. That's why 64₁₀ = 100₈. Historically used in UNIX/Linux file permissions (chmod 755 = rwxr-xr-x) and memory addressing in older 8-bit systems.
Dateirechte unter Linux
Linux-Zugriffsrechte (chmod) verwenden drei Oktalziffern: Eigentümer, Gruppe, andere. Jede Ziffer ist die Summe der Rechte: lesen=4, schreiben=2, ausführen=1. Beispiel: chmod 755 = rwxr-xr-x (7=r+w+x, 5=r+x, 5=r+x). chmod 644 = rw-r--r--.
Praktische Anwendungen
File permissions: chmod 400 (read only), chmod 755 (full), chmod 600 (private). Used rarely in Python and Java. In older IBM System/360 used for disk addressing. Conversion: 64₁₀ = 100₈, 255₁₀ = 377₈.