Computing mirroring real-life. Espresso is not conducive to sleep and neither it seems is the Asus S-presso small-form-factor PC.
I have an Asus S-presso small-form-factor PC that runs Ubuntu and is on all the time, because it is the print server for our Canon i950 ink jet printer.
Now my wife and I have decided to be more green/eco-friendly and to save money on our electricity bill, so running a computer 24/7 is not really helpful in that regard.
I got out my Kill-A-Watt last night and measured power demand of a power strip that serves the computer, printer, monitor, external hard drives, USB hub, etc. With the computer running in its normal steady state, usage seemed to be around 160 to 180 watts. With the computer powered off, I believe it went down to around 18 or so. If I actually unplugged the computer, I think it went down to around 11 (the computer has a front-panel display with a clock when it’s off but plugged in). Even after unplugging the computer and monitor and printer and such, I don’t think I got the usage below 9 watts (Perhaps the power strip LEDs?).
Powering the computer off at night and when we’re not using the printer would save power but would be a bit inconvenient. Ideally, we could have it suspend to RAM or disk and then use Wake on LAN to wake it up when we need it.
Well, I checked the BIOS settings and made sure that all the ACPI and APM stuff looked in order and then I booted up Ubuntu and tried to suspend it via GNOME’s power management stuff. Well, the computer yawned a bit and the monitor lost signal and the computer went to sleep for all of a second or two before promptly waking up and presenting the password prompt to unlock the screen. I tried this a few times. I checked the BIOS to see if anything was set to wakable and I couldn’t find anything.
Then I tried hibernating. First there was the obstacle that I apparently had no swap partition. Apparently during one of my upgrades, partition names changed and my
fstab was no longer up to date so I had been unknowingly running without a swap partition. Oops. Well, that was easy to fix with a quick edit to
fstab and an invocation of
swapon. Now I tried to do a hibernate. The system jumped to text mode and dutifully wrote out the contents of RAM to swap, as I observed with the nice percentage done progress indicator. Then the system powered down and power usage was down to a nice 18 watts. Only problem was that pressing keys didn’t wake it up and when I pressed the power button on the machine, it did a complete cold boot and never made any attempt to restore the hibernated state.
After that I looked through the repository at a confusing bunch of power management stuff, including
uswsusp and I tried to install some of them (some of them conflict with others) and had no luck. I also had no luck throttling the speed of my processor (Pentium 4 3.0 GHz)- it appears that my processor doesn’t support SpeedStep or the like.
Eventually, it was late and I gave up and powered the computer down for the night. I guess I will power the computer down every night and power it on in the morning, at least for now. I may give some thought to getting a little $50 Ethernet USB 2.0 print server box (e.g.: IOgear GPSU21, RJ45/USB 2.0, $53.99 ; though I recall these things often require special client software and don’t typically support bidirectional communication) or maybe just getting rid of the ink jet (which costs a lot of money in ink cartridges anyway) and replacing it with a networked laser printer (e.g.: Samsung ML-2571N, $109.99 after $50.00 Mail-In Rebate).