Slashdot Mirror
Ask Slashdot: Reliable Powering of ATX Systems?
David Muir Sharnoff
writes in with this question:
"ATX power supplies don't supply power unless the motherboard says to
turn on. Many motherboards do not have a setting of: 'supply
power all the time.' This means that ATX systems
cannot safely be used a servers. Anyone know of
an ATX power supply that ignores signal? "
More appropriately: does anyone know of an ATX
motherboard/power supply/case combination where powering
is similar to AT systems?
If you are worried about the system not coming back up automatically after a power outage, some motherboards have a BIOS option that controls systen behavior in such a condition. I beleive that an ABIT BH-6 has this.
How about turning them OFF? I have seen new machines that can't be turned off without unplugging. AND with no reset button!
The SuperMicro ATX mb I have has an option in the bios about what to do after the power goes out:
'Always off' will leave the power off after a power failure (whether the machine was on or off)
'Always on' will always have the power turn on after a power failure (even if it was off?)
'Last State' (as if you can't guess) will turn it back on if it was on, or leave it off if it was off.
Last State is what I usually use, but Always Off is a good idea if the power goes on and off a lot (like during a thunderstorm).
I've seen similar options in the BIOS of other mbs I've toyed with recently, too.
-Ross
Worse yet... I have an an ABIT AX6 MB which will
not get past POST unless the power is disconnected
and reconnected unless you go to the CMOS setup
screen first. Nobody has ever been able to tell
me why this might be.
I believe several (all?) of the Intel motherboards have an always-on jumper.
I have no problem using the powersupply without the motherboard attached, in fact for low amp work I have used a spare powersupply to great success. But more practicly, to try and ward off some seemingly power related problems I was having I installed a second power supply in my linux machine. This second power supply runs all of my cdroms and a couple of harddrives, but it does not have any motherboard attached.
some mobos don't have the connector at all (such my DEC board mentioned above).
hmmm... i have never seen a bios that couldnt get by a keyboard. are you sure your looking at the correct thing? some bios's do have a specific option for turning off the keyboard but every bios i have ever seen always has an option (usually on the first screen under the floppy settings) for ignoring errors on bootup. it will still give you the POST warning beeps that there isnt a keyboard but it wont halt the bootup process.
...boards like my FIC VA-503+ that has BOTH AT and ATX Power connectors? (anmd no giant heatsink)
Also the Tyan Tsunami has a bios setting
While we are talking about ATX cases and powersupplies, anyone know what the small 5V 2 pin connector attached to the power supply is used for? This is the connector type similar to that of the reset switch, keylock switch, speaker, etc. I've never seen an use for that.
Have you configured power management in the kernel and recompiled and installed?
If you're going to have it off anyway, it should be unplugged to prevent lightning damage.
But, if you are buying a new machine, it might as well be ATX.
If it is the electrical bill you worried about, don't. Torn off monitor, wich is the biggest power drawer and let you're box help find aliens while it is idleing. I have mine installed as a screensvaer and whenever I am not around I am looking for aliens.... To get the program (in many flavors unix nt 9x) goto http://setiathome.ssl.berkeley.edu
What BIOS revision are you running? Certainly v4.51 doesn't seem to exhibit this behaviour, at least not on my system. All this accomplishes is not being able to turn off your computer without holding the power button for 4 seconds.
I'd like to know, however, how to enable my BH6 to power up automatically.
Cheers.
We ran into ATX power supplies when building up a
"box of disks" for a server we were building. Stupid ATX wanted a m/b, or so we thought. Get the
ATX specs, look at the connector pinout. Hmmmm.
The "pat-pend, ATX motherboard emulator" saved
the day - a paper clip shoved into the power connector to ground the signal (can't recall what
pin). Then we did it properly and rewired the
connector. No problemo.
Essentially, it's a rip off of the old Macintosh "soft power" feature where you can start up the machine by pressing the power key on the keyboard and shut off the machine by choosing shutdown from the system menu and/or pressing the power key on the keyboard a second time. Only, as with all features ripped off from the Macintosh, the PC version is a little bit less elegant.
At any rate, the ATX power supply has a "trickle" or standby power output that continues to supply a small amount of electrical power to the motherboard even when the system is off. The portion of the motherboard supplied is just enough logic such that when you press the soft power button on the front of an ATX machine, the power management logic signals the power supply to enable the high current outputs which supply power to the rest of the motherboard in normal operation. Once the computer is powered up, it can power itself back off by writing to the necessary registers of the power management logic and/or you can press the soft power button on the front of the machine a second time. (BTW - this is a lot like the power management function built into current computer monitors - only instead of actually having a soft power button, the monitor watches the video sync signals, when they are present the monitor powers up the high voltage circuits of the power supply and when the sync signals go away, the monitor goes back into power save mode.)
Unfortunately, PC keyboards don't have a power on key like the Mac - would be nice if they would have added that as opposed to Windoze keys. ASUS was able to hack a keyboard power on feature into some of their ATX boards (I think specifically those with the BX chipset) where in the BIOS you can enable the space bar as a power on key. Kinda funky.
bah. just use the network time daemon and update from an atomic clock somewhere..loads of em are free and available.
I used to work in a College lab that used IBM computers with ATX Power supplies. Every time there was a power failure and the power would come back on, all the computers in the lab would come on and we would have to go around shutting all of them off. Another lab with ATX Based Gateways would do the same thing. There would be some times when I would come into work, and know that the power must have went off because all of the computers were on. I always considered it a pain, but also a probable way of causing damage to the computers as well. Some power sags would cause them to come on as well. I could only imagine what would happen if the power blinked on and off a couple of times in only a short time.
ATX also has a 3.3V power source, which reduces the power dissipated by the onboard voltage regulators powering the CPU. That is a good thing, both for head and for power consumption (the switchiing regulators in power supplies are much more efficient than the linear regulators on motherboards)
: The GA686BXD (Dual PII) doesn't have this jumber
From page 15 in GA-6BXD manual:
J:12 System After Ac Back
Open: Soft Off
Short Full on/ Soft Off
-1, Flamebait? For this? Go suck an egg, censorship lovers!
Sweet, just how I predicted. These moderator assholes are running around making BEEEG mistakes... Eventually CmdrTaco will get PISSED OFF and change things back to the old days!
Eventually, those of us who want REAL opinions are just gonna make our own damn forums.
The idea is that the fan is blowing directly over the CPU. This means you've got a large volume of air blowing over the heatsink. The purpose was to save system makers the price of a CPU fan.
And yeah, it's a dumb idea.
Nope I have the same bios. You should double check that what you are suggesting actually works. Turn it on, unplug it and plug it back in, is it on?
I thought it was best to leave a system plugged in while tinkering. The reasoning behind that being that it'll be grounded, so you can discharge any static build-up by touching the case or power supply. Is this wrong?
Anonymous Coward
It's hard to be sure, but WTX seems to require two of Slot 1 (patented by Intel). Since I never reward companies that want to prevent competition, do I have to ignore WTX to keep Socket 7?
While that does sound logical, you would be safest to unplug the cord in any event. Afterall, accidentally electrocuting yourself is probably not a pleasant experience.
... but not the computer) to discharge any excess static electricty. Then, unless you plan on walking around the room shuffling your feet across the carpet, while you're tinkering, then you won't have anything to worry about, and grounding yourself will not be a priority.
Most reasons for making sure you're sufficiently grounded before tinkering, is because you do not want to accidentally short anything through an unintentional discharge of static electricity.
You can avoid this by touching some type of conductive material around you (e.g.: Something metal, your brother/sister, etc
My (several weeks new) system using an ATX power supply has mysteriously power ON itself a few times already. It is quite annoying. And I noticed that every time it happens the clock would also be off a few hours. The VCRs don't blink so I don't think it's power failure, and in any case I've set the BIOS to stay off after one.
What would be the most likely culpit?
1) Motherboard
2) Power supply
3) Power socket without ground wire
Intel 440lx and newer have power settings allowing power to be restored to last state. I think ECS may have this same feature.
Although I have heard of problems with win9x and UPS's. if they shutdown the os before power drops, technically the board won't boot, this can be fixed by using the always on setting.
Why would you need to get a PCI or AGP monochrome card to drive your seccondary displays, jsut go to your local used hardware store (many universitys have these) or go trashing and pick up whatever old PCI video cards you can find, it is really rather simple to do multiheaded consoles with multiple PCI video cards as you need only address a different memory space and dont have to worry about using up IRQs, it is however a bit more difficult to do multiheaded X.
The SuperMicro motherboards are nice from
... sorry, it's been a long day :-)
this point of view.
BUT, they have a stupid BIOS that will not
boot without requiring you have a keyboard
in place!!! PLEASE - all BIOS manufacturers -
HAVE AN OPTION IN THE BIOS FOR CHECKING
KEYBOARDS!
Grrr
How about turning them OFF? I have seen new machines that can't be turned off without unplugging.
Sometimes it is useful to remotely restart a
crashed server by cycling its power. Like in
colocation situations.
home would not bootup after a powershutdown.
After some investigation I found that most
ATX mobo's have a setting in their bios to
powerup after a powercycle.
-aj-
I thought ATX was a PC case description (I see it in ads). Now it seems its a power supply and what does this have to do with being able to be a server? This proto nerd is confused.
I had a motherboard (DEC AlphaPC 164) that didn't produce the DC-OK (aka PC-ON)signal. This is pin 14 on the ATX motherboard connector. You can cut this wire (usually green colored) and the adjacent black (pin 15) wire above the connector and wire them together with a wire nut so that it is always on whenever the power cord is plugged in. Or connect these two wires to a new switch and replace the ATX style switch on your case with a standard AT-like switch (this is what I did). I bought the switch at radio Shack for under a dollar. Works great. The only thing the DC-OK wire does is tell the power supply to go from sleep state to full power state. It does this when the pin is grounded. The black wire #15 is one of those unneeded ground wires that can be redirected to this task. I was educated to this method by PC Power and Cooling (www.pcpowercool.com) which is probably the finest producer of power supplies out there. Good luck.
I hav a related question.
Is it possible to have the ATX power switch act
like an SGI power switch(I press the button, I
runs shutdown then turns off).
Likewise with reset. If I press reset, can I have it run 'reboot'? Can I even control what happens with the reset button?(I just unplugged the thing, since it does nothing good(safe))
WTX will replace ATX for server boxes. It appears to be a good spec to me.
WTX.ORG
The ATX specification can be found here:
.htm
http://www.teleport.com/~atx/spec/index
(Boy I hope this message get moderated up.
That would be keen.)
Not where I come from - where I come from it just means that those motherboards can't be safely used as servers.
If you get a decent motherboard which has the required power setting, why would you need to play silly buggers with the power supply unit?
check under the APM options, if you're doing a make menuconfig it will have an option of 'power off computer on shutdown' or something similar to that. As long as your M/B supports it, the machine does magically turn off on shutdown then.
On the Asus mainboard I use there's a setting in the BIOS that will cause the powerswitch to act as a suspend switch. A daemon could watch for suspend requests and run shutdown when it sees 'em.
The Asus mainboard (don't have the model number handy; the machine and docs are about a mile away) I use can be configured to switch on whenever
The Asus mainboard (don't have the model number handy; the machine and docs are about a mile away) I use can be configured in the BIOS to be 'always on', but it also has a setting so that the power switch must be held down for four seconds in order to switch the machine off. It's a nice feature for servers because it protects you from accidentally pressing the power switch, and if you really do want to turn off the power it's easier than untaping the metal plate that's covering the switch (we really do use little metal plates to protect switches at work).
What I want to know is, what does ATX get me that makes it worth having to toss out all of my venerable AT form factor hardware in order to upgrade my machines? And is it going to be possible to buy an AT K7 motherboard?
I know for a fact that the ASUS P2BF has a "AC Power Fail Auto-Restart" BIOS option and the Intel Nightshade has a "Restore Power State" BIOS option that will turn the power on automatically if it was on when AC power was lost (i.e. power was not turned off via the front panel switch).
Send mail here if you want to reach me.
Posted by jap33:
The Gigabyte GA686BX motherboard has a jumper on it allowing the computer to automatically start up when the power is restored. However, check before you buy because not all of the Gigabyte ATX motherboards have this option.
Posted by el_steevo:
From the power supply wires coming from the power supply in the case to the MOBO, short the green wire to ground. This will give you power all of the time.
OK, this leans slightly toward the "off topic" category but...
:)
I have an epox kp6bs board in a supermicro 750 case. Under Windows, the date / time is reflected fine, even when the machine puts itself to sleep. Under linux, however, it appears that date / time stops when the machine goes to sleep. Therefore, while the machie has been running continuously under linux since May 20th, it thinks that the (current) date is May 21st ('cause it only runs the clock when I'm actually using it).
I don't recall, but I believe that I have power management set to something like 1 hour but suspend completely disabled. If I reboot the machine it picks up the correct date just fine. Anybody got a clue what's doing this to me and how to fix it?
Who am I?
Why am here?
Where is the chocolate?
What is your Slash Rating?
You should short the jumper that receives the signal from the case's power button.
Wade
Oh yeah: sometimes the power-off-after-five-seconds happens when you release the button. With my home PC (ASUS P2B-L), the 4-second power off happens as documented. But with my Compaq, it powers down only after I release the button.
Wade.
No, using NTP (network time protocol) alone won't work because (1) between the time that the system resumes from sleep and the NTP daemon realizes that something is wrong, the clock will be off; (2) the NTP daemon will try to calculate the clock's drift and calculate a correction factor, and that factor will keep changing as the system sleeps for various lengths of time, "skipping" different-sized chunks each time.
apmd, on the other hand, is wired into the APM system and restores the time from the RTC immediately upon resume. apmd+NTP could work very well together.
This might be related to the Linux "use" at Lucas Digital that caused some discussion last week. Then again it might not and it just made me think of it.
;)
If I had a rack of Linux servers with ATX supplies (which, coincidentally, I do), and wanted to make sure they came back on when power was lost (doh, didn't think of that, what are you running a server without a UPS for anyway???), then I might use a spare 386 or 486 I've got kicking around to do it.
Its a piece of cake to wire a relay to a parallel port, there's schematics all over the place on the net to do it. Trim the power supply's "on" pins, wire them to the relay, and you could easy control the power of 8 systems from the parallel port with maybe $40 worth of hardware. Its not exactly what the question was asking, but it might be useful. Maybe Slashdot needs something like this for when the machine misbehaves.
Also useful in case of an errant init 0 instead of init 6...
Alternately, I think those Matrix Orbital displays with the keypad interface also have eight digital outputs on them, you could wire one of those to a serial port, and trigger the relays with those outputs. Running some monitoring software to put the status of the machines on the LCD, you've got a nifty monitoring/control system.
Here's what it will cost to run a computer all month for your electric bill at home if you pay $0.08 per kilowatt hour:
40 watts * 0.08 cents/1000watthour *24hours * 30 days
=$2.30
If you get the industrial rate at $0.02 per kilowatt hour, that will be about $0.58 per box.
UPS supplies seem to draw much more. They seem to have a type of saturation transformer where the iron core is intentionally saturated with excessive current to give a well regulated and safe voltage to your computer including isolating it from the mains.
Perhaps your AB-BH6 is an older revision.
This works with an Award BIOS. Press RESET and press Delete key to enter setup. Open the "Power Managmement Settings" menu. Set the "Power Button Override" to "Enable" Save and Exit.
Should be. I'm running an AT motherboard. In Windows 95 (I'm at work, but I'm demonstrating that it can be done) on a standard AT clone PC, when you go to Control Panel, then go to Power. "Allow Windows to Manage This System's Power". "Add Suspend to Start Menu". Etc. Under Display, Go to the Screen Saver command, "Energy saving features of Display", etc. All doable under Linux using the APM drivers in the kernel and apmd. Look in the documentation in your motherboard's or bios's documentation under Power Management. This road's been traveled. Just do a search for Power Management.
Two key things:
1. Your BIOS. Assuming post 1994 (probably before, just a guess) , you should have power management options in there.
2. APM and APMD. Might require a kernel recompile to enable APM in Linux, but that's extensively documented. See first post about link to Battery-Power-HOWTO (similar techniques, section 3.x)
--I hate people when they're not polite -"Psycho Killer", Talking Heads
Look for APM (advanced Power Management) support in the BIOS and Linux. Should be doable. I've never looked into it, but it's the basic principle. Most modern bioses support sleep mode, which is functionally idle-type mode. Of course, you'll want an EnergyStar-certified monitor. Most modern monitors are. This sort of information was really big around six years ago, with major manufactuers shipping low-power systems, such as the IBM EV1(?) which had an LCD monitor (a rarity at the time, and expensive). If you look through PC Magazine there should be some information about Green PC's around 92 or 93. Additionally, I believe there's some info on power managament at: ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO/mini/Ba ttery-Powered
Particularly Sections 3.1-3.4 (which describes APM)
Also HDPARM, which can be used to reduce the spin rate on the Hard Drive to reduce the power used.
But the question is why? Aside from the good for the environment angle, there isn't a pressing need for it. A computer only draws about as much power as an light bulb (last spec I heard about PC power consumption). If you REALLY want to save power, shut off the system. Sleep mode draws ~2-4 watts afaik.
Hope this helps,
--I hate people when they're not polite -"Psycho Killer", Talking Heads
Doesn't the power supply have to be on for the motherboard to do anything?
In an "Ask Slashdot" that wasn't posted I asked about making my computers power efficient. Is ATX relevant here? Since I'm out of the house for 12 or more hours at a time it would be great to have my computer turn its power supply down to idle when I'm gone.
Is that what ATX does? I've never come across any comparison of AT vs ATX so I've just stuck with AT upgrading piecewise from my first AT case. If ATX allows variable control of the power supply its worth the switch.
I get power from my old AT even when nothing's connected?!?!?...
FRA: STFU GTFO
off topic? Is it possible to tell win{9[5,8],NT}
not to shut the power on shutdown?
Can you set this in other Unices(!Linux)?
FRA: STFU GTFO
Of course you never do lose power to your server because you are using a UPS, right?!?!? :)
:)
The way things run around here, I have the system page me when the power fails, and then shuts down normally. I like to be there before it boots up again, because I almost certainly have not got the bootup scripts correct to bring it online perfectly. Having it not power on would be a "feature" for me.
While we're on the (admittedly off-topic)subject, I've got a Giga-Byte Socket 5 board with a "Dallas" type RTC chip that keeps time beautifully--until I power up the board. I can set the time in the CMOS setup screen, save the changes, boot to some or no operating system, turn off the system, disconnect the power supply, come back a month later with a different power supply or the same one, different or same keyboard, video card, CPU, etc., and the time shown on the Cmos setup screen will reflect the passage of that month, but any time the board is under power the clock "freezes" (stops counting seconds) for as long as power is applied. I've downloaded and flashed the BIOS to no avail. Anybody got a clue?
I see even classic Slashdot is now pretty much unusable on dial up anymore.
This is the correct answer-for the "speed" LED's. If it was for fans it would be 12 volt and not 5. ,by the way, aren't exactly precision frequency counter readouts since you can set them to read any number between 00 and 199--I've got one set to switch between "HI" and "LO".
Those LED displays
A better use for those LED displays would be to use it as a readout of the temperature inside the case. Anyone got a (cheap, low parts count) circuit handy?
I see even classic Slashdot is now pretty much unusable on dial up anymore.
The only linear computer supplies I ever saw in surplus catalogs came from discontinued mainframes, not bankrupt PC manufacturers.
Linear power supplies take the current from the wall socket and run it through the primary winding of a transformer. The secondary winding (in vacuum tube days a voltage step up, current step down--for solid-state circuits a voltage step down, current step up) passes the same wattage (voltage times current, sort of--it's a little more complicated with alternating current than with direct current)--minus what gets lost, due to less than 100% efficiency, and turns into heat--to rectifiers which "re-route" the alternating cycles so that the current flows in the same direction instead of reversing 60 times per second. This makes it direct current, but now the voltage goes from zero up to whatever the peak is and then back down to zero 120 times per second, so various passive (and sometimes active) components are used to filter and regulate the voltage. If the incoming frequency is higher than 60 Hz then smaller, lighter (less expensive) transformers and passive filtering components can be used. This is the reason for 400 Hz generators on aircraft, to save weight and space, although, in the case of aircraft, not money. The higher frequency = smaller, lighter, cheaper components relationship is also taken advantage of in switching supplies where the alternating current from the wall socket goes straight to the rectifiers, is changed into pulsating direct current, filtered to "average out" the pulsations, and sent to transistors which turn on and off somewhere in the neighborhood of 20,000 to 40,000 times per second. This results in a "pulsed" direct current which can be stepped up or down in voltage with a transformer just as with alternating current, but at the much higher frequency a smaller, lighter, cheaper transformer can be used. In both cases (linear and switching)the transformer electrically isolates the power supply's output from the wall socket supplied input.
I see even classic Slashdot is now pretty much unusable on dial up anymore.
So, you should be able to hack it together to have that pin permanently grounded, so that the PS is always on. I haven't tried this; I think it should work fine, but don't blame me if your motherboard burns!
There's also more info on ATX at http://www.teleport.com/~atx/
I have once or twice disconnected my motherboard and run my power supply with no problems (accaching my drive to another machine). AT does not have a "smart" power supply, so it should not know whether it has a motherboard hooked up or not.
I run a voicemail server on an ATX system and yes, I do have a UPS attached. But if the power outage is a long one, I still want the system to power back up on restoration (and I can't afford a huge UPS farm!)
All I'm saying is this information is useful, and I'll be acting on it!
One major problem that I have experienced wth ATX power supplies is that since the fan is mounted on a horizontal plane it seems to be more prone to wear and "chuffing."
ATX motherboards are great since they reduce ribbon cable clutter. However, if you must use ATX you should ALWAYS get a motherboard that has AT power supply connectors (most aftermarket boards do). You'll save at least $30 and be able to get higher-rated power supplies for less money. You also won't have the annoying power button problems.
Kris
Kriston J. Rehberg
http://kriston.net/
Kriston
UPSs are just supposed to keep you up and running until your 'tested weekly' backup generator is online. :-)
Awesome furniture, accessories and cabinetry in Santa Rosa, CA: http://humanity-home.com/
Yes, but for the time being, I think this is a Win98 Second Edition feature only. It's called ACPI and it's an all encompassing *thing*. Aside from using an unshareable IRQ (#9), it also gives you a soft power switch and another means to provide resource enumeration.
It is actually a rather nice idea, as it tries to sidestep some of the hackish nature of APM.
Keep in mind even the shipping version of Win98SE has horribly buggy ACPI support, even though it tries to be very conservative about when to enable this. My guess is W2K will also have some form of ACPI support.
You can find some more information somewhere on telebit (I think).
The revolution will be mocked
Every power supply I have ever worked with, other than an actual AT has had tabs on the power connector that prevent you from puting the connectors on backward with out forcing them.
One day people will learn the folly of Winbloze, Linux Rules!
Yeah, I have the same problem. I have a P166MMX ATX gateway system that runs Debian and winNT (I only ever go into NT for Quicken and some Photoshop (GIMP's antialiasing of text SUCKS)). I never turn off at school - but try to not leave on at home (no network, no computing). The problem is, after a few hours off - the damn thing just turns itself on! The first few times it really confused me, because i'd wake up and the computer be'd on. Then I caught it in the act, and have been wondering ever since.
Haven't been able to figure it out, but I put it on one of those control base things that let you CUT the power to your box - and that obviously fixed it.
1) Turn it on.
2) Unplug the power switch cable from the motherboard.
100% safe. That's all it is when dealing with an ATX. The only problem then is if someone phsyically unplugs the power cord.
I got the impression that the author wasn't worried about outages, but about the motherboard failing to 'ask' for power... It's just one more thing that can go wrong, and isn't worth the convenience (the ability to automatically power-off like a Mac) on a server system.
/* The beatings will continue until morale improves. */
The NEC Versa LX notebook I just got performs a Windows shutdown when the power switch is cycled. If the power switch is held down for three seconds it does a normal power off without the shutdown. Kind neat.
Eagles may soar, but weasels don't get sucked into jet engines.
The Intel AL440LX has an auto-power on option in the same place as the restore option. So I wouldn't be surpised if the N440BX has the same option.
Of course with the restore option (and the P2B-F's in that matter) it only works if you never use the ATX front-panel power switch... but if you never wire that it's not an issue :)
As to the original question... I'd just advise using Intel/Abit/Asus etc... mobos or something like that which DO have the always power on feature.
Its not worth it. Most if not all cases come with power supplies. Also, replacement power supplies are relatively inexpensive.
Finally, the old power supplies were/are very inefficient; they work by using transformers to step down the voltage. The newer power supplies, including the ATX supply, are switching power supplies. This means that more of the power actually gets to the motherboard and less is wasted in the conversion.
-- Error: Cannot find file REALITY.SYS - Universe halted, please reboot!
Most ATX motherboards should have a BIOS setting for "restore power after power failure" or some such. Usually there are three settings; "on", "off", and "previous state".
--
Twoflower
At hardware and auto parts stores you can get solderless connectors which tap a wire into an existing wire. You can use two of them to add a wire which connects the wires for pin 14 and a neighboring wire. They're usually blue plastic with a metal tab which you push into the two wires. Faster than soldering and can be removed for maintenance.
I'm using an alton 747 bx board that has AT and ATX power connectors and also has a hardware jumper to disable ATX power functions. I ended up with this setup just by coincidence after I had done some upgrades and had enough spare parts for another server (except cpu). I have and old 386 tower sitting around so I got an AT-slim ps from pc power and cooling and then got a p2-450 to put on the board. Since the board accepts an AT powersupply, there is no danger of it powering down through some ATX function.
Hmm.. that sounds vaguely familiar. A friend of mine's computer mysteriously powers on during lightning storms and come to think of it, it's an ATX mobo. Of course, he *should* unplug his computer from the outlet during these situations, and it could be the cause of his current computer woes (or maybe it's just Windows 95). Anyone else have this "problem" (strange powerups)?
If you were me, you'd be good lookin'. - six string samurai
All of the Asus P2B series boards that I've used do power on when the cord is first plugged in; in other words, when power is first applied to the PS, the board turns on. So that takes care of power failures, etc. I haven't checked for relevant BIOS settings, but if there are any, they apparently default to this behavior.
Because the power switch goes through the MB instead of to the power supply it makes it more difficult to narrow down problems with a computer. Is it the Power Supply? Is it the Motherboard? You can't tell without popping out the power supply and trying a known good one.
Additionally, is it just me or are the ATX power supplies more fragile than AT's? I've had to replace two of them myself in the period of one year, and my brother had to replace his a few months after he got his. I don't know about him, but I have a UPS (APC) so I know my power is clean. And I've been buying good quality power supplies. Argghh, I like the ATX case design thing-ma-bobs, but I REALLY don't like the power supplies. Is it just me? Am I cursed? Or have other's experienced my travails?
BTW, this is very recent so it's not because I'm using pre 2.01 compliant power supplies.
There're a couple of options
Some ABIT motherboards can be strapped with a
jumper between the reset and power switch connectors to make them act in an 'always on'
fashion like AT motherboards do.
If you feel like experimenting a bit, you can
look in electronics parts catalogs for POST
transistors... these basically act like delayed
momentary-on relays. One lead goes to +5V,
the others go to the power-switch jumper.
--Z
I have never, ever, going all the way back to 4.77 MHz 8088 systems, seen a PC system that used anything but a switching power supply. I believe my old Z-80 'bigboard' system (early 80's vintage) used a linear supply. Is that what you mean by 'old power supply'?
In the old days (in the "PC" time scale) power supplies were sold separate from cases (and all for big bucks) but it's correct that it's almost always a package deal these days. And cases are getting to be really, really chintzy lately. (not quite aluminum foil yet, but the beancounters are working on it...)
It isn't possible to power an ATX motherboard with an AT power supply. The ATX power supplies produce an additional 3.2 volt output not present on a standard AT power supply. That is why modern motherboards that work with AT power supplies always have a big heatsinked part on them, to regulate and produce the lower voltage not availabe from an AT power supply (which only supplies +-5 and +-12 volts). A cord adaptor to allow you to use an AT supply on an ATX motherboard would have to incorporate a pretty fancy inline DC-DC converter to give the MB the voltages/current it needs.
Reset is a pretty cruel and unforgiving beast.
I suspect that a power-switch event could be linked to trigger a shutdown somehow, maybe in the inittable (?) like control-alt-delete is. It seems like pretty low-level hardware stuff, though. Does anybody know if power-switch handling is part of the ATX specification (which I believe is available at Intel somewhere) to make it worth the effort of something like this? (it would be a nightmare to have it be architecture dependent with tons of variations)
What kind of software do you use to make your server page you when it is about to go down?
:o)
Try
Big Brother... it works wonderfully for this.. (assuming your UPSd logs things like that
Funny, the first thing we do at my workplace when the power goes out is start turning machines off. It (the UPS) can supply approximately 30-40 minutes for about 300 computers. So, yes, we don't worry about brief power outages, but then, what are we supposed to do, wait until there are 5 minutes left and THEN start powering them all down? [Especially since some of them take more than 10 minutes to shut down. Well, only one.]
--- Where's my X.400 protocol decoder?
Does anybody know if it is possible to "keep the power up" with Asus P5A? I couldn't find the way how to do it. Asus P2B has simle option in bios setup which says "turn the power on after power failure" but I couldn't find it anywhere on P5A. :-(
My tekram motherboard will boot up after power
failure if I change a jumper. i assume this is
why u are concerned about this..power failure
Some of the comments I've seen hit it on the head: The Brand + Model + Revision of Motherboard you buy is key for ANY system (esp. a server).
/. you can usually tell which are which)
:) ) You'll want to make sure the PS is compliant with ATX 2.01 to be on the safe side too.
:(
Myself I don't like buying anything I haven't researched to death; I also really want to hear what other people's experience has been with the stuff. (note: people I trust... not some script kiddie; though on
Checking Tom's Site and Ars Techina to see what they think doesn't hurt either.
As far the Power-Always-On feature you want well, 3 things:
1) I would not recommend any soldering at all as your warranty will most likely go out the window. This can be a very bad thing in a corporate environment.
2) Most high quality Motherboards come with either a CMOS or Jumper setting (or combo) which tells the PS what to do when power is applied.
3) A good case goes a long way... both in ensuring you have a quality PS, and that you won't slice your fingers when you need to work on it. (Can we have a poll on how many times we've done that?
As far as personal choices, I'm a big fan of both Supermicro Motherboards and Cases - my personal fav is the SC-701a style case - it's a beauty! but unfortunately its soon to be discontinued...
Anyway, just my $0.02 (which is worth even less as its Canadian...)
I used to have a cool sig.
Once my ATX case gave me a nightmare. To put this short, I tried powering up, but the damn thing wouldn't start. Now whenever this happens I usually pull out the connector strip between the mobo and power supply. Most of the problems seem to happen when '95 crashes while shutting down, somehow failing to reset the mobo to 'off'. So if you're ATX won't power up, try reinserting the PS>mobo power cable.
* Intelligence is like 4-wheel drive. It only allows you get stuck in more remote places. -- Garr
ASUS was able to hack a keyboard power on feature into some of their ATX boards (I think specifically those with the BX chipset) where in the BIOS you can enable the space bar as a power on key.
My Asus P2B and P2B-S boards have a quirk in the KBPWR feature: it causes the system to reset instead of power down after the OS tells it to turn off.
Also, the KBPWR feature draws so much current (it's powering the keyboard controller) that the 850mA on the +5VSB lead isn't enough to use KBPWR and WOL simultaneously.
An AT power supply has a "power ok" lead from the motherboard that tells it to switch on or not. If you turn on an AT supply without this lead connected, the power supply won't turn on. XT power supplies, on the other hand, are completely dumb (I use them for testing drives, in fact)
My Asus has a setting in the BIOS called "Wake on Power fail". Works great.
Most ATX motherboards will have a jumper on the board that will disable automatic power managment or at least tell the power supply to aways stay on and ignore the front panel power switch. I seem to remember Mylex boards having a jumper J13 that did this.
This was an issue for me at I wanted to power cycle machines with X10 cubes remotely (ie. from home) if the machine seriously wedged.
On my motherboard there is a jumper that ignores the ATX power/motherboard problem and always stays on. very nifty. it is a gigabyte board..
http://www.1053.org -=We use big words=-
I have a Supermicro P6GDE (Dual PII 400, GX chipset) that has a jumper on the MB to choose, "Bios Power Stater, or Always on..."
As soon as I through the switch on the back of the powersupply its on, and if that switch is left in the on position then it comes on when the power returns after a black out, etc.
Note the case is a supermicro ATX750 or something(which is really an Antec Case and Powersupply) and it seems to be designed just for this...
VANBO
[ This is an expanded version of an earlier posting. It also has an useful subject. ]
A while back, I did some current measurements on my ATX PC. Here're the results:
PC off, monitor off: 0.11A
PC off, monitor in "power save/standby": 0.13A
[ This is an expanded version of an earlier posting. It also has an useful subject. ]
A while back, I did some current measurements on my ATX PC. Here are the results:
PC off, monitor off: 0.11A
PC off, monitor in "power save/standby": 0.13A
A while back, I did some current measurements on my ATX PC. Here are the results:
The eye-opener is the fact that, even with everything "off", the system is still eating 12 or so watts. I was expecting maybe 8W, but not 12W. ATX systems can eat significant power, even when off.
Note that the "full on" current was measured just after Win98 had finished booting. A CPU-intensive program like Quake or Unreal wasn't running. It would be interesting to see how much of a difference, if any, there would be.
It's also interesting to note that, if I disconnect all cables from the power strip and then measure the current, the power strip is drawing 0.01A (1.2W). This is probably leakage current from the surge suppression in the power strip (or measurement error in the ammeter).
These numbers are probably on the high side, as my system has a Voodoo 2 and two hard disks. Detailed specs:
Side note: from measuring my girlfriend's PC, which is virtually identical to mine except she has only one IBM hard disk and no Voodoo2 card, the Voodoo2 card and extra hard disk use up 0.27A or 32.4W. Most of this is probably from the Voodoo2 card.
OK, this is slightly off-topic, but close. :-)
I have a good AT supply, but many MoBo's nowadays only have ATX power connectors. Is there a way to convert an AT connector to fit an ATX connection on the board?
TIA!
> The newer power supplies, including the ATX supply, are switching power supplies. This means that more of the power actually gets to the motherboard and less is wasted in the conversion.
True, I know that most cases come with power supplies. But I have 2 new AT switching power supplies now. That's why I want a converter.
My motherboard, a Tyan S1836DLUAN-GX has a BIOS setting to switch the function of the power supply like discussed in other messages. Just thought I'd like to use my freedom of speech.