Arthur arthursstuffforsale@redacted.invalid wrote:
Hi, Can anyone recommend a brand of Uninterruptible power supply that works well with OSX 10.4? I'm thinking of the ones that have a usb port and software to shut down the mac cleanly if the UPS kicks in.
Do you really mean an uninterruptible power supply? Why should the mac need to be shut down if its power supply cannot be interrupted?
On Thu, 15 Mar 2007 06:47:49 -0400, Arthur wrote (in article 55smilF25dmb1U1@redacted.invalid):
Hi, Can anyone recommend a brand of Uninterruptible power supply that works well with OSX 10.4? I'm thinking of the ones that have a usb port and software to shut down the mac cleanly if the UPS kicks in. Arthur
APC. Belkin. Presumably others.
Alec McKenzie find@redacted.invalid wrote:
Arthur arthursstuffforsale@redacted.invalid wrote:
Hi, Can anyone recommend a brand of Uninterruptible power supply that works well with OSX 10.4? I'm thinking of the ones that have a usb port and software to shut down the mac cleanly if the UPS kicks in.
Do you really mean an uninterruptible power supply? Why should the mac need to be shut down if its power supply cannot be interrupted?
Yes, he does. The 'Uninterruptable' bit in UPS refers to the non-interruption of the transfer from Mains to Battery power, and the hope that mains is restored before the battery runs down, so it can transfer the supply back to mains, and recharge the battery.
However, the battery life is not infinite: so if the mains is not restored before the battery dies, the computer should shut down cleanly by monitoring the battery level in the UPS. Exactly how long you get on a battery depends upon the capacity of the battery, and the load put upon it. It can be anything from hours to less than ten minutes.
APC UPS's are great for this, I have one connected to my PMG5 via USB. It works.
Completely uninterruptable power is a pipe dream - your generator will run out of fuel, be it diesel, solar, or nuclear. Or your transmission lines will be broken either by the cleaner pulling out the plug, or someone dropping a JCB bucket through the cable. We had both last year, and sometimes the power came back within the battery life of the UPS, sometimes it didn't, and the servers shut themselves down cleanly.
Cheers,
On Thu, 15 Mar 2007 06:56:40 -0400, Alec McKenzie wrote (in article find-2755D3.10564015032007@redacted.invalid):
Arthur arthursstuffforsale@redacted.invalid wrote:
Hi, Can anyone recommend a brand of Uninterruptible power supply that works well with OSX 10.4? I'm thinking of the ones that have a usb port and software to shut down the mac cleanly if the UPS kicks in.
Do you really mean an uninterruptible power supply? Why should the mac need to be shut down if its power supply cannot be interrupted?
Because the UPS's battery only lasts for a short time, typically 5 to 30 minutes depending on the UPS and the load on it. My Belkin will keep my eMac and iMac running for 25 minutes after power goes out, before the low power indicator signals the Macs that it's time to shut down. My APCs do similar duty for my other main computers.
There are two types of battery-backed power systems: SPSes, Standby Power Systems, and UPSes, Uninterruptible Power Systems. SPSes have batteries which are trickle-charged by AC and a very fast switch, which cuts the battery and a DC-to-AC converter circuit in within a fraction of a second of mains power going off. There is also a surge protector built into the SPS; power from mains power runs through the surge protector, some is sent off to trickle-charge the battery, and the rest is sent to power equipment attached to the SPS, making a SPS under normal conditions a very large, very expensive, surge protector. When there is a major power event on mains power and the surge protector cuts out the mains, the SPS battery switch will usually cut in so fast that the computers that it is supporting won't have time to have a power-system crash. Even the best switches, though, take time to cut in, and there will be power events involving your equipment, which is a Bad Thing(tm). UPSes take mains power, convert it to DC, feed the battery, take battery power, convert it to AC, and feed your equipment. They don't need a switch because the battery and the DC-to-AC system are always in the circuit. When mains power cuts out, the battery stops being charged but otherwise the UPS continues to work as it normally does... until the battery runs completely flat, of course. There is no chance of a power event on your equipment, so long as it obeys the shut-down-now signal from the UPS. It should be noted that UPS batteries need to be replaced considerably more often than SPS batteries, as UPS batteries are constantly being charged and discharged. UPSes are more expensive in the first place than SPSes, and cost more to run. Many people prefer UPSes just the same because nothing gets through to your equipment from the mains power when you are connected to a UPS, as mains power is converted to DC and then back to AC, ironing out frequency problems, surges, sags, whatever. Some people have problem with the square-wave output of many UPSes. I have not noticed any significant problems due to square-wave AC, and I've been using equipment attached to UPSes for a very long time. Certainly there are far fewer problems with equipment attached to UPSes than with equipment connected to mains power either directly or via SPSes or surge protectors.
On 2007-03-15 10:47:49 +0000, Arthur arthursstuffforsale@redacted.invalid said:
Hi, Can anyone recommend a brand of Uninterruptible power supply that works well with OSX 10.4? I'm thinking of the ones that have a usb port and software to shut down the mac cleanly if the UPS kicks in. Arthur
I have an APC cs 350 and it works well - connects to my Intel iMac via USB and I seem to recall it was fairly cheapt (?£40 ish). Mind you, I haven't had a power cut yet, but did turn the UPS off at the mains and my iMac stayed on happily. You can set it up to shut down under certain conditions, such as when there is only 5 minutes of battery life left on the UPS. I am running 10.4.9 with it and no probs.
tricky wrote:
I have an APC cs 350 and it works well - connects to my Intel iMac via =
USB and I seem to recall it was fairly cheapt (?=A340 ish). =20
Thanks for the replies everyone. Arthur