Re: harddisk suspend/sleep management
Re: harddisk suspend/sleep management
- Subject: Re: harddisk suspend/sleep management
- From: Ethan Bold <email@hidden>
- Date: Tue, 3 Dec 2002 14:13:22 -0800
Hi Matthias -
Nothing like noflushd is implemented in darwin/os x. It's certainly an
"interesting" idea. I know far too little about linux power management,
so I'm not sure how easily this concept would convert. Note than, in OS
X, disk spindown requests originate and execute within the kernel.
There's not as much user-space interaction as I perceive linux has.
If you want to get started, checkout these opensource projects from cvs
and start grepping. These are pointers to driver-level power management
code. If you want to add hooks into the filesystem to prevent spin-up,
check xnu/bsd/vfs(?).
Disk specific power management:
IOATABlockStorage
IOSCSIArchitectureModelFamily
General kernel power management code (which all device drivers inherit):
xnu
Files:
xnu/iokit/Kernel/IOServicePM.cpp
see IO
Service::setIdleTimerPeriod() and IO
Service::start_PM_idle_timer()
I started this email with the intention of going into moderate detail
about how this works, but I'm too tired. If you're seriously interested
in implementing noflushd, get looking at the code and write back with
specific questions. I'm happy to help. So GET HACKING :)
-ethan
On Sunday, December 1, 2002, at 09:29 am, Matthias Kretschmer wrote:
Hello!
I was thinking about the noflushd project
(http://noflushd.sourceforge.net/) and thought, this should be
possible for darwin, too. The logic for suppressing write access to
the hdd should be easy if proper asynchron write is implemented. I
wouldn't say to port noflushd, but implement some other simple tool
which handles this (of course if it is less work to port :) ). So but
this needs fundamental support from the kernel. I don't really know
where to begin to look at. Or is something like this already
implemented?
--
Greetings
Matthias Kretschmer
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