Research On Linux Operating System's Embedded Mechanism And Fast Start

This thesis Researches on Linux Operating System's Embedded mechanism and fast start. I mainly research into the following: After analyzing the linux core original codes, I will compile a new linux core which is to satisfy the Embedded System. An integrated linux operating system includes not only a core, but also embedded C library and embedded shell. A picture needs displaying when the system is booting. By compiling new scripts, I am to realize the system's fast start and fast exit.Firstly, the thesis discusses how to modify the linux core original codes. Because some aspects of linux operating system are not expected by embedded system, linux core original codes must be modified. The thesis analyzes and then modifies linux core original codes in four aspects: Memory Management; Process Management; File System; Network Management. This thesis aims at expatiating on how to cover page-swapping mechanism in linux core. Semaphore mechanism is a an effective means of synchronizing tasks which compete against each other to enter the same critical section.Most of the semaphores used by linux core are mutex semaphores.But linux core doesn't detach the operations on mutex semaphores from those on counting semaphores.The list of tasks which wait to enter the critical section is not optimalized by linux core either.Another question is that the linux core doesn't resolve the priority inversion problems caused by using mutex semaphore.This paper brings out a new method in order to improve the application of mutex semaphore to linux core.In order to apply linux to embedded system, I must cut the whole linux operating system including its core original codes. A typical linux operating system contains three main software layers: linux core> C library and application programs. This thesis expounds how to make a linux operating system miniature by modifying linux kernel, disposing linux kernel, using embedded C library and embedded shell.As default, lines of texts will be displayed on the console when linux system starting. This is redundant to embedded system's users. To substitute for that, this thesis brings out a new method which can retain a picture when linux is booting.Many a minute will be exhausted when the linux system starts or exits. This is too long to await for embedded system's users. This thesis is to shorten the whole procedure of start or exit after analyzing it carefully.