# Computer States **URL:** \ **Category:** Ruby\ **Created:** [December 18, 2009, 5:04am UTC](https://www.ruby-forum.com/t/computer-states/180349 "2009-12-18T05:04:11Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![xogue](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/x/ce73a5/32.png) [@xogue](https://www.ruby-forum.com/u/xogue)\ **Post date:** [December 18, 2009, 5:04am UTC](https://www.ruby-forum.com/t/computer-states/180349/1 "2009-12-18T05:04:11Z")
Hey all, I’m looking for a way to programmatically wake the computer up from sleep state, preferably at a certain time, rather than after certain amount of time, but ill make due with whatever solution there might be. any suggestions or help is much appreciated. i’ve been searching for a couple weeks on and off for a way to do this, and can only find the wake-on-lan, or wake-on wan (would work fine for some, but id rather this feature not fail should the user not have a router or an internet connection.) Thanks in Advance, ``` X ``` ---
**Author:** ![xogue](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/x/ce73a5/32.png) [@xogue](https://www.ruby-forum.com/u/xogue)\ **Post date:** [December 18, 2009, 5:21am UTC](https://www.ruby-forum.com/t/computer-states/180349/2 "2009-12-18T05:21:38Z")
On Thursday 17 December 2009 10:04:20 pm Brandon B. wrote: > I’m looking for a way to programmatically wake the computer up from > sleep state, preferably at a certain time, rather than after certain > amount of time, but ill make due with whatever solution there might be. I suspect most BIOSes have this feature, but I have no idea how to access it programmatically. I did find this: > **[NVRAM WakeUp](https://sourceforge.net/projects/nvram-wakeup/)** > > Download NVRAM WakeUp for free. This is a small program that reads and writes the WakeUp time in the BIOS. This is done via /dev/nvram on recent kernels (\>2.4.6, including 2.6.x) or, alternatively, via direct ISA access. I have no idea how well it works, though, and it’s probably going to be system-specific. ---
**Author:** ![xogue](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/x/ce73a5/32.png) [@xogue](https://www.ruby-forum.com/u/xogue)\ **Post date:** [December 18, 2009, 5:28am UTC](https://www.ruby-forum.com/t/computer-states/180349/3 "2009-12-18T05:28:29Z")
> I suspect most BIOSes have this feature, but I have no idea how to > access it i was thinking about bios features, but being able to access and change certain features of it will either give the user alot of hassle or myself in having to change things on the many different bios versions there are, if it is even possible to change it programmatically, not to mention the warning label that would have to be included by going that route. > programmatically. I did find this: > > [NVRAM WakeUp download | SourceForge.net](http://sourceforge.net/projects/nvram-wakeup/) will definetly have to check this out, might be able to salvage something from it, with a bit of research. > I have no idea how well it works, though, and it’s probably going to be > system-specific. i would like to have it be cross-platform, but i dont have a problem with testing for the OS is need be, thanks David. ---
**Author:** ![xogue](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/x/ce73a5/32.png) [@xogue](https://www.ruby-forum.com/u/xogue)\ **Post date:** [December 18, 2009, 9:00pm UTC](https://www.ruby-forum.com/t/computer-states/180349/4 "2009-12-18T21:00:15Z")
> You probably want to access [ACPI - Wikipedia](http://en.wikipedia.org/wiki/ACPI) > How you do that is OS specific, since it’s fairly lowlevel. A very > superficial search for “Ruby ACPI library” didn’t produce any real hits, > so it might be that you have to go low level to call the Windows, Linux, > and Mac OS X APIs for ACPI. yea, i expected as much, which if fine, i just dont know how to go about doing so… maybe there is a way to send a “wake-up” packet to the ram, or nvram, and have it execute it from there at a given time? dont know too much about what can and cant be performed like that so, if im way off base, please forgive me. > However, it is my understanding that ACPI can’t wake a computer from a > Hibernating/Suspend to Disk (ACPI S4) from within the sleep state. > Hope this helps at least a little. yea it has helped, thank you. i have found a linux wake up procedure that i might be able to tether to my needs, if it works ` #!/usr/bin/ruby require 'time' wake_time = Time.parse(ARGV[0]) wake_time += 24 * 60 * 60 if wake_time < Time.now File.open('/proc/acpi/alarm', 'w') {|f| f << wake_time.utc.strftime (%Y-%m-%d %H:%M:%S')} system('/etc/acpi/sleep.sh force') ` like i said, this is for linux, obviously, which if it works takes out one of my issues, but what i dont know is if there is anything like the above file locations for windows or mac? well, ill keep looking around, maybe i can dig up something else using this as a search tool, any additional help or advice is much appreciated. ---
**Author:** ![xogue](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/x/ce73a5/32.png) [@xogue](https://www.ruby-forum.com/u/xogue)\ **Post date:** [December 18, 2009, 9:17pm UTC](https://www.ruby-forum.com/t/computer-states/180349/5 "2009-12-18T21:17:18Z")
On 18.12.2009 21:00, Brandon B. wrote: > yea, i expected as much, which if fine, i just dont know how to go about > doing so… maybe there is a way to send a “wake-up” packet to the ram, > or nvram, and have it execute it from there at a given time? dont know > too much about what can and cant be performed like that so, if im way > off base, please forgive me. You’d’ve to read the ACPI spec, I’m afraid, what does what, if you want to go really, really low level, since I stay away from the Dark Arts. 😉 > like i said, this is for linux, obviously, which if it works takes out > one of my issues, but what i dont know is if there is anything like the > above file locations for windows or mac? With Windows, there’s the win32api gem (pre-installed in the Once Click Installer and/or the new RubyInstaller), providing access to the Windows API, so you can call the Windows system calls to send the computer to sleep. Or, maybe, you can shell out to “shutdown”, but I’m not well versed in Windows CLI tools, at least to send to computer to sleep. I’m pretty sure that WakeOn needs an API call, though. With Macs, and this is from my dim memory, there’s CocoaRuby (I think that’s what it is called, googling for “cocoa ruby” should unearth something), which accomplishes roughly the same as the win32api gem. Keep in mind, you can run into binary compatibility issues on Windows (depending on the Ruby variant installed, there’s mswin32, and mingw32, the latter being included in the new RubyInstaller), as well as on Mac (depending on the Mac Os X API changes). And that ain’t even touching on JRuby. So, “true” cross-platform compatibility will be difficult, to say the least. Mind, just pick the Ruby versions you are able to report, and you’ll be fine, don’t let me scare you. 🙂 ---
**Author:** ![xogue](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/x/ce73a5/32.png) [@xogue](https://www.ruby-forum.com/u/xogue)\ **Post date:** [December 18, 2009, 8:07am UTC](https://www.ruby-forum.com/t/computer-states/180349/6 "2009-12-18T08:07:14Z")
On 18.12.2009 05:28, Brandon B. wrote: > > I suspect most BIOSes have this feature, but I have no idea how to > > access it > > i was thinking about bios features, but being able to access and change > certain features of it will either give the user alot of hassle or > myself in having to change things on the many different bios versions > there are, if it is even possible to change it programmatically, not to > mention the warning label that would have to be included by going that > route. You probably want to access [ACPI - Wikipedia](http://en.wikipedia.org/wiki/ACPI) How you do that is OS specific, since it’s fairly lowlevel. A very superficial search for “Ruby ACPI library” didn’t produce any real hits, so it might be that you have to go low level to call the Windows, Linux, and Mac OS X APIs for ACPI. However, it is my understanding that ACPI can’t wake a computer from a Hibernating/Suspend to Disk (ACPI S4) from within the sleep state. Hope this helps at least a little.