General > General Technical Chat
Why aren't computers designed to handle power failure?
Berni:
--- Quote from: SilverSolder on June 22, 2020, 01:27:27 am ---All mine can do is basically flap one of the pins in that serial port on the back (non standard, so requires a special cable) when the power fails, which signals the computer to shut down gracefully (if it has the right software running that can react to the flapping pin).
Today, it would probably be designed to send some kind of cryptic messages that are difficult or impossible to work with...
--- End quote ---
These days they use USB with a HID driver. Still not quite all standard but there is open source software that works with most of the popular brands and models.
I run a NAS server with Unraid and a UPS connected via USB. Does a pretty good job of it too as it shows up with a ton of information about the UPS such as battery state, current load, estimated backup time remaining, last self test status...etc and can be given a command to turn off the UPS once the OS has finished its shutdown process. Not sure what these periodic self tests do, but it sounds like it switches over to battery power for a few seconds (Maybe its using the load to measure the battery internal resistance to determine if its going to die) and i have no idea how is it supposed to notify me of a failed self test. Will it send a error over the USB or will it beep? No idea, but its only like 2 years old so the battery shouldn't fail yet.
madires:
--- Quote from: SilverSolder on June 21, 2020, 11:17:55 pm ---What software do you use, if any?
--- End quote ---
Another open source project is NUT (Network UPS tools) which supports most UPS vendors and is quite versatile. It also comes with some features intended for professional use. One drawback is that it doesn't support APC's MODBUS protocol yet (you would have to use an AP9605).
SilverSolder:
--- Quote from: Berni on June 22, 2020, 06:20:22 am ---
--- Quote from: SilverSolder on June 22, 2020, 01:27:27 am ---All mine can do is basically flap one of the pins in that serial port on the back (non standard, so requires a special cable) when the power fails, which signals the computer to shut down gracefully (if it has the right software running that can react to the flapping pin).
Today, it would probably be designed to send some kind of cryptic messages that are difficult or impossible to work with...
--- End quote ---
These days they use USB with a HID driver. Still not quite all standard but there is open source software that works with most of the popular brands and models.
I run a NAS server with Unraid and a UPS connected via USB. Does a pretty good job of it too as it shows up with a ton of information about the UPS such as battery state, current load, estimated backup time remaining, last self test status...etc and can be given a command to turn off the UPS once the OS has finished its shutdown process. Not sure what these periodic self tests do, but it sounds like it switches over to battery power for a few seconds (Maybe its using the load to measure the battery internal resistance to determine if its going to die) and i have no idea how is it supposed to notify me of a failed self test. Will it send a error over the USB or will it beep? No idea, but its only like 2 years old so the battery shouldn't fail yet.
--- End quote ---
Interesting, it might not be so hard to get an Arduino to act as the HID, converting between the "flapping serial pin" and HID, so modern software can be used... but then, it takes away from the authentic experience of using ancient equipment! :D
Raj:
--- Quote from: SilverSolder on June 22, 2020, 01:05:57 pm ---
--- Quote from: Berni on June 22, 2020, 06:20:22 am ---
--- Quote from: SilverSolder on June 22, 2020, 01:27:27 am ---All mine can do is basically flap one of the pins in that serial port on the back (non standard, so requires a special cable) when the power fails, which signals the computer to shut down gracefully (if it has the right software running that can react to the flapping pin).
Today, it would probably be designed to send some kind of cryptic messages that are difficult or impossible to work with...
--- End quote ---
These days they use USB with a HID driver. Still not quite all standard but there is open source software that works with most of the popular brands and models.
I run a NAS server with Unraid and a UPS connected via USB. Does a pretty good job of it too as it shows up with a ton of information about the UPS such as battery state, current load, estimated backup time remaining, last self test status...etc and can be given a command to turn off the UPS once the OS has finished its shutdown process. Not sure what these periodic self tests do, but it sounds like it switches over to battery power for a few seconds (Maybe its using the load to measure the battery internal resistance to determine if its going to die) and i have no idea how is it supposed to notify me of a failed self test. Will it send a error over the USB or will it beep? No idea, but its only like 2 years old so the battery shouldn't fail yet.
--- End quote ---
Interesting, it might not be so hard to get an Arduino to act as the HID, converting between the "flapping serial pin" and HID, so modern software can be used... but then, it takes away from the authentic experience of using ancient equipment! :D
--- End quote ---
Indeed...I remember that keyboards used to have shutdown button. It should be just an hour of work to make a device that does the intended function.
bluey:
A. Use a laptop
B. Modern pcs with journalling filesystems are pretty robust without power protection except for the work you lose that hasn’t been autosaved. Hence A.
C. Server class machines with dual redundant power supplies, battery backed caches, and external ups cost more. For home, see A.
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