Open AccessUbiFOS: A Small Real‐Time Operating System for Embedded Systems
Author(s) -
Ahn HeeJoong,
Cho MoonHaeng,
Jung MyoungJo,
Kim YongHee,
Kim JooMan,
Lee CheolHoon
Publication year - 2007
Publication title -
etri journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 46
eISSN - 2233-7326
pISSN - 1225-6463
DOI - 10.4218/etrij.07.0506.0025
Subject(s) - computer science , embedded system , scheduling (production processes) , bitmap , context switch , arm9 , embedded operating system , fixed priority pre emptive scheduling , operating system , real time computing , dynamic priority scheduling , computer network , rate monotonic scheduling , engineering , operations management , schedule , software , computer vision
The ubiquitous flexible operating system (UbiFOS) is a real‐time operating system designed for cost‐conscious, low‐power, small to medium‐sized embedded systems such as cellular phones, MP3 players, and wearable computers. It offers efficient real‐time operating system services like multi‐task scheduling, memory management, inter‐task communication and synchronization, and timers while keeping the kernel size to just a few to tens of kilobytes. For flexibility, UbiFOS uses various task scheduling policies such as cyclic time‐slice (round‐robin), priority‐based preemption with round‐robin, priority‐based preemptive, and bitmap. When there are less than 64 tasks, bitmap scheduling is the best policy. The scheduling overhead is under 9 µs on the ARM926EJ processor. UbiFOS also provides the flexibility for user to select from several inter‐task communication techniques according to their applications. We ported UbiFOS on the ARM9‐based DVD player (20 kB), the Calm16‐based MP3 player (under 7 kB), and the ATmega128‐based ubiquitous sensor node (under 6 kB). Also, we adopted the dynamic power management (DPM) scheme. Comparative experimental results show that UbiFOS could save energy up to 30% using DPM.