computer on or off?

[omeyehead]

Having recently worked at various corporate/institutional sites the past few months I've noticed that they leave their computers on all the time. Working with induction motors I know there is a 2X to 3X current surge upon motor startup. This is typically when they fail. Do DC motors exhibit this same phenomenon? With hard drive platter speeds at 7K plus, is it better to leave it running or shut it down?
What do the techies here at sysopt think?

[SPEEDO]

I think that you will find many different answers to this question, Some prefer to leave them on all the time others like to shut them off, Let's see what the ratio will be.
Personally I shut mine off.

SPEEDO

[OC Guy]

When I get some better cooling, mine is staying on 24/7.(Wonder if Boeing has any extra fans laying around? http://www.sysopt.com/forum/wink.gif)

[RayH]

I live in California, Land of the Electricity Shortage. I turn my computer off when not in use.

The only electrical appliances that are running 24/7 in my house are clocks and the refrigerator! Short do happen!

Computers only have a useful span of so many years anyway. Surely, you'll replace it before you wear it out turning it off and on a couple of times a day!

[eagle1]

I shut mine off too! It's safer and the electric bills doesn't get that high!! http://www.sysopt.com/forum/wink.gif

[NDC]

I may be wrong on this, but I believe omeyehead is talking about the hard disk shutting down after X amount of minutes. If that's the question, I've heard different things from different people. I would also like to know the answer to this question...

Is it better to have the hard disk spinning continously or letting power management shut it down when there is no hard disk activity after X amount of time?

[eagle1]

I was reffering to shutting down the system but to answer the HD question, yes... I let Windows automatically shut off the HD after 1 hour idle.!

I think if you have the HD spinning continously it creates more heat thus shorting the life span of the drive.! So it'd be wise (at least that's my opinion) to control your hd usage and power consumption!

[Richard_Cranium72]

The MTBF of most HD's is some 30,000 hrs if I remember correctly.

The biggest problem AFAIK leaving them running is already mentioned, HEAT

The Gyroscope effect continually presses on the bearings regardless of whether the drive is being used or not.

Perhaps Quantum's new Hydro bearings will curtail some of these issues, however my AS series Quantums still generate significant heat.

I belong to the shut-em-down crowd
HD
and for the total system, I shut totally down for a 30 minute absence.

DrVette

[Bsdboy]

All mine are on 24/7 crunching Geonome (100% load).

Bsdboy

[Bovon]

Having lost one system to lightning, I shut mine down if I am away from the house. I also shut down at night. If a lightning storm happens up during online time, I pull the modem plug first, then shut down. No amount of surge protection can save a modem from a high spike shot. The sensitive electronics in a modem will not allow too much filtering or protection, the signals used to perform the data transfer is too small to allow a high degree of lightning arresting.

[darrelld]

All of mine run 24/7 except the laptop. I do let PM shut off the monitors. The oldest one is 3 years and still going strong. BTW...all are OC'd. Mine line of thinking is kinda strange though, I know I will upgrade and replace hardware, I would feel better about it if there was actually something wrong with what I was replacing. The problem is in reality nothing,except one PSU fan, has ever gone bad, as a result I have 4 pc's.
Although, now with the power situation being what it is in the Northwest I will probably start to shut them off.

[otheos]

actually it's not that simple.

as far as power consumption goes, starting up does not require more power than a typical seek does (max consumption).

As for chances to fail? Heat I hear you say:

When the drive is spinning it performs thermal calibrations every now and then in a read/write operation or a dedicated calibration operation if idle (you can hear this with some drives when they're idle doing a high pitch whine every 5-10minutes in idle mode). Thermal calibrations allow the heads to be positions exactly and compensate for the platter contraction/expansion with heat.

When the drive is not rotating and it wakes up the first thing it does is a thermal calibration so again heat effects are imediately overcome.

So as far as temperature is within operation limits the drive will operate fine.

I know this is not a direct answer to your question, but covers the heat issue. The only reason I can think of that a spin down/up can cause the drive to fail is the stress in the mechanical parts as they overcome their inertia.

[Cody]

Depends. About half of the time, I will leave it on. It is normally on continously (Unless I completely wreck my Windows 2000 Networking Grid and have to search through spindles and spindles and piles and piles of CD's to find Windows 2000 so I can get online!!!!), but 2 or 3 days a week I leave it on to run DNETC.

It is also normally on continously from 4:00PM to 8:00PM... that's about it though.

[darrelld]

LOL http://www.sysopt.com/forum/smile.gif

[Goldwingnut]

Socorro NM is one of the most lightning-happy spots in America. My house has taken 2 lightning strikes through the power lines while I was home. I can't say how many times this has happened while I was gone. There is no doubt when it happens - all the electric lights get VERY bright, then VERY dim.

I shut down the circuit breakers when I'm gone.

[NDC]

The only reason I can think of that a spin down/up can cause the drive to fail is the stress in the mechanical parts as they overcome their inertia.

So would you say it would be a better idea to have the hard disk not spin down?

[This message has been edited by NDC (edited 09-02-2001).]

[omeyehead]

NDC on your last post:
This was kind of what I was driving at. On induction motors at startup there is an increased amount of stress. If you monitor current at startup typically it takes two to three times the amperage to make the stator start turning. Generally, this is when windings cook or capacitors blow. I was wondering (not being real knowledgable with DC motors) if this holds true for a DC motor as well.

[Psycho Logical]

Click here (http://www.pcguide.com/care/care/gen/power.htm) for some factors to consider and some ideas.

Check out "Thermal Stress vs. Wearout" and "Pros and Cons".

[[Neo770]]

I leave my computer on all day and off all night. My HDD's are not set to spin down but my monitor is after 1 hour.

My compter is also runing the ECCp-109 client.

[Sizume]

i work at CSFBDirect.com once known as DLJDirect.com

we always leave the systems on because we are running much older systems.. containing a large number of files and eats up hard drive space and memory which would cause the pc's to start up slower or sometimes not connect to local intranet so we all figure leaving it on would save us hassle and 20 minutes?

[PassnThru]

I used to leave one computer up 24/7 - the monitor did blank out after an hour or so. I really think the part that continuous operations hurts the most is the monitor - but that's not a problem if you let it blank out after awhile. As for the hard drive, who knows. I have a sneaking suspicion that yes - it probably does matter. But the difference is so small that no one would ever notice it outside the lab. I'll probably be replacing that hard drive in a few years anyway because they'll finally come up with one that can actually keep up with an ATA/100 transfer rate. Don't think of it as a parts failure = it's an upgrade opportunity!!
BTW - the only reason one doesn't run 24/7 now is I rebuilt it and used a case with plenty of fans. It's too loud to run continuously.

[omeyehead]

Thanks for the input from all, question was kinda twofold computer and hard drive. I shut down if I plan to be away for awhile, but got to wondering after working at places where I noticed they leave them on 24/7. Got to thinking about AC motors and that got me wondering about the motor on my hard drives.

[SPEEDO]

I have always looked at it like this, A company can afford to replace parts a lot more frequently than I can.
Besides don't most of them do there backups during off hours??

SPEEDO

[Ed_S]

I used to leave most of mine on continuously to avoid start-up wear & tear. It's a full tower, stands on hardwood floor, and runs with case open.

Luckily I was right here when a p/s failed a couple years ago. Shorted somehow, and I wasn't tinkering with it that day either!
Sparks flew, circuit blew. Scared the h3ll out of me, even moreso thinking "what if I hadn't been here?" or "what if the breaker hadn't tripped??"

Got away with minimal damage, just a p/s actually. Pure luck. But it taught me, made me reconsider & prioritize.
No matter WHAT, nothing in this box is worth losing the house over!!
It's now on a UPS, plugged to a dedicated circuit with a GFI breaker. And it's off if not in use. None of the others are even plugged in unless in use.

[otheos]

NDC

yes I believe it is not a good idea to have the hard disks spin down. Even with thermal calibration taking place immediately (and hence the chances of a head crush are minimal durin spin up -but still more that if it wasn't spun down at all) there are three other factors:

1. Mechanical stress on the moving parts.

2. Thermal stress on all parts (the cycle of heating cooling etc)

3. Sudden power consumption.

The first is not too much of an issue but still all parts that are asked to overcome their inertia are stressed.

The second is the most important. Heat stress builds up and with a drive spinning down after 1 hour the cycle is quite intense for both mechanical and electronic parts. This is true for all electronic parts. Wear of constant power on state will kill a device slower than a heat stress cycle. There is no universal equation but it is mostly true.

While DC motors do not require 3x the amperage to start (like AC motors do), the sudden demand for power from a very low power state can be impredictible. While chances are low, increasing the number of times obviously increases the chances.

[This message has been edited by otheos (edited 09-03-2001).]

[Sweeper]

If mine were a bit quieter I would leave it on. But as stated above in another post, it's just to noisy to leave on. I usually will leave it on during the day (weekends) when I am home and off at night, but during the week it stays off when I am not using it.
My Dad is just the opposite. He has a newer Dell, and it's much quieter. He leaves it on 24/7. Just turns off the monitor when he's done using it.

Sweeper