id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	field_blocks	field_dependson	field_seealso
414	Graceful system shutdown	Jakub Jermář		"Design and implement graceful shutdown of HelenOS.


 Details::
 The current support for shutdown in HelenOS is rather minimal. 
 It is possible to halt the CPUs or reboot the machine.
 What is missing is a ''graceful'' way to tell running tasks that the system is about to be shut down.
 For example, the reboot sequence now consists of forceful kill of all existing tasks.[[br]]
 The goal is to design and implement way to notify tasks of imminent shutdown (reboot) to allow them terminate in a clean and consistent way.
 The design decisions must reflect microkernel-specific issues, such as order of shutdown of vital services (e. g. VFS, naming service or drivers).


 What Gains and Benefits will this bring?::
 The benefits of this task come at rather low level but are nevertheless very important.
 Graceful shutdown means that drivers could terminate communication with hardware in a predictable manner or that filesystem servers would be able to unmount file systems cleanly.


 Difficulty::
 Medium to difficult. The solution will require work both in kernel and in userspace.


 Required skills::
 A successful applicant will have good skills of programming in the C languages and the ability to survive in a non-standard non-POSIX application environment.


 Possible mentors::
 HelenOS Core Team
"	enhancement	new	major		helenos/unspecified	mainline		gsoc12, needswork