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Thread: Opinions on running your computer 24/7 and sideways

  1. #1
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    Opinions on running your computer 24/7 and sideways

    If this is the wrong forum please forgive me and feel free to move this where you please.

    Some opinions on leaving your computer on 24 hours a day and mounting
    your machine sideways.
    This is the version that was included in the Frequently Asked Questions
    file until May 1990:

    There's a lot of stress placed on the system when it first comes up.
    Generally, you should leave your system running if you plan to return
    within the next few hours or so; if you don't expect to be using it for
    a day or so, whether or not you turn it off is a personal judgement call.

    Monitors aren't the same, though, since images can get "burned into"
    the phosphor. Use a screen blanker, or turn it off if you'll be away
    for more than five or ten minutes.

    As for mounting it sideways: The most common myth about this is that
    it will make the disk drive bearings wear unevenly. If you look at the
    manufacturer's information when you buy a disk drive, you will see
    that it is warrantied in any position *except*upside-down* (with the
    defect label down). However, the disk may hang slightly differently in
    the bearings after being placed on its side, so if you plan on
    mounting your system sideways, you should back up your hard disk while
    it's level, then mount your system sideways and do a low-level
    reformat of your hard disk and restore it from the backup you made. If
    you do this you shouldn't have problems.
    From: chuck@eng.umd.edu (Chuck Harris)
    Subject: Computer on 24hrs.day?
    Date: 30 Mar 90

    I can provide some info on the phenomonon. Semiconductors have failure
    curves that look like:

    | \ /...
    | \ /
    |_____\______________ ... ___/__
    0 100 1E6 = ~100 years
    Hours of use

    The failures in the first 100 hours are some times called Infant mortality.
    I'm not sure at all about the 1E6 hours (Lets say it's a lot of hours!)

    The first 100 hours failures are the reason the most reputable manufacturers
    will "Burn-in" new systems. Statistics shows that there is little gain in
    confidence by burn-ins much longer than 100 hours.

    NASA (I think) found that semiconductors that had been left on for a long,
    long time were very likely to fail if their power was cycled off then on again.

    However, statistics showed that the same semiconductor if just left on would
    continue to work almost indefinitly.

    As I recall the failures due to cycling power occured while the power was off.
    it had something to do with the transistor's junctions migrating too close
    together while power was off, then when power was turned on, the transistor
    failed because the junctions were shorted. (power being on continuously
    apparently prevents this) Anyone know more about this?

    These are the tests that everyone alludes to when they tell you to leave
    computers and other electronics on all the time for greater life. They
    only mean something if you have a statistically large number of transistors
    (the transistors need to be from different lots not just a large number on an
    IC) in your system, and you are using the system for a LARGE number of hours.

    Your individual PC does NOT have a statistically large number of semiconductors
    in it. The entire country's PC's do. 100 years is a long time.

    Conclusions that I think you should draw from this diatribe:

    1) Big computers that have millions of IC's in them perhaps should
    be left on.
    2) Small computers (PC's etc) It just won't matter.

    Note: Failures of mechanical parts are nothing like that of semiconductors!
    (You know, disk drives, switches, keyboards, fans, etc.)

    I wish I could provide references to all of what I have stated, but
    I can't easily. This is stuff that I have gleaned from years as an Engineer,
    and many many hours of college course work. So some settling may have
    occurred :-)

    Chuck Harris
    C.F. Harris - Consulting
    From: nicholso@hpcuha.HP.COM (Ron Nicholson)
    Subject: Re: Dusty Dorms. WAS: Re: Computer on 24hrs.day? (yes or no)
    Message-ID: <10350001@hpcuha.HP.COM>
    Date: 30 Mar 90 23:29:35 GMT

    gregk@ubvax.UB.Com (Greg Kendall) / 6:59 pm Mar 28, 1990 / writes:
    >I've heard a lot of claims about how it's "harder" on the PC to power
    >up than to leave it on. I have yet to hear of any real data on failure
    >rates. ...
    Long long ago, in a far away place, when I worked for a high volume
    computer manufacturer, I ran across some real statistics. Some
    experiments had been done on the difference in failure rates between
    continuous burn-in and power cycling. My dim recollection is that there
    was a significant increase in the infant mortality rate of the group
    that underwent power cycling.

    The sample size was large enough to be statistically convincing. The
    primary cause of the failures was due to thermal shock on solder joints,
    IC bonds, sockets and connectors.

    Alas I no longer have access to the details of that experiment. What I
    now do is to frequently power cycle new equipment (while it's still under
    warranty of course) to shake out the lemons, and to minimize power cycles
    thereafter. I still have seen no good data on electromechanical
    equipment, like disk drives.
    Ronald H. Nicholson, Jr. Hewlett Packard
    uucp: nicholso@hpda.HP.COM Cupertino, CA
    From: dan@tinton.tinton.ccur.com
    Subject: Computer on 24hrs a day?
    Date: 5 Apr 90

    Power conditioning must play a part in the equation. If one's AC supply is
    relatively dirty and one has limited power conditioning equipment, then leaving
    one's system on constantly leaves it open to large power glitches wreaking
    From: uunet!tiamat!quintro!bpdsun1!rmf (Rob Finley)
    Subject: Re: Computer on 24hrs.day? (yes or no)
    Date: 15 Apr 90 06:38:02 GMT

    My floppy drive fails to read some disks when cold. So, I leave it
    on. After three years, the only thing that died is the cheap 12V fan
    in my UL listed power supply. $15 and a trip to Radio Shmuck did the
    trick. It's still ticking.

    Just be sure to use a good screen blanker program. Most of our machines
    at work are never turned off.

    But. My 386 at work ate two hard drives and three motherboards before
    they replaced the power supply. The +5v line ran at 5.2v while the
    other voltages were acceptable with low electrical noise. New supply
    and it works great.

    Before deciding whether to leave it on or not. Consider these points:

    Does your system draw air into the box through a vent on the back?
    If you feel air being blown out the vent on the power supply, then
    it is most likely sucking it in through the biggest hole: your
    floppy drive. When air comes in through the drive door, it drops the
    dust it was carrying all over your machine, mostly on your disk drive.
    Remedy: replace the power supply with one that has the fan going
    in the right direction. Swapping the Red and Black wires on it won't
    do. You will cause irrepairable damage to the solid-state controller
    (they don't have brushes like conventional DC motors to control noise).
    I had to open the power supply box (after removing it from my machine)
    unscrew the fan mounting hardware and turn it over so that it draws air
    in from the vent that sticks out the back of the cabinet when installed.

    With your fan now drawing air from one place, you can tape a piece of
    foam or air filter material over that vent to catch a large percentage
    of the dust before it gets inside. But, you must check the filter
    regularly. The entire system may be at risk with a blocked air filter.
    Or, if anything, your expansion boards will attract the dust before it
    reaches your floppy drives. Unfortunately, too much dust on the
    motherboard or expansion boards will insulate the chips and prevent
    them from keeping cool.

    If you have large expansion boards or full height hard drives,
    look into adding additional fans. Some cabinets allow you to have a
    second one on the front end of the expansion card cage. If you don't
    want to open your machine and it overheats or attracts dust in all
    the wrong places, turn it off if possible. Machines today are durable.

    Safety warning. If you don't feel comfortable opening your machine,
    find someone who is. If your dealer doesn't feel comfortable, find
    another dealer. The one you have now probably can't fix it if it dies.
    The power supply circuit can still hold a charge when it is unplugged.
    You shouldn't have to touch any of the circuits on the power supply
    board. You aren't rewiring it, you're flipping the fan over and putting
    the screws back in.

    That wasn't hard. Was it?
    quintro!bpdsun1!rmf@lll-winken.llnl.gov uunet!tiamat!quintro!bpdsun1!rmf
    From: kabra437@pallas.athenanet.com (Ken Abrams)
    Subject: leaving PC on
    Date: 8 Aug 90

    In article <hart.650028982@blackjack> hart@blackjack.dt.navy.mil (Michael Hart) writes:
    >I refer you to the "light bulb law". That law being: When do light bulbs
    >burn out?? _when you turn them on_ There is a large surge of current through

    Even though most of the components in a PC are NOT light bulbs ( and don't
    behave like one either), I would agree with you that leaving it on is best
    if the ONLY consideration was hardware reliability (and it is connected to
    a stable power source). As I see it, however, hardware reliability is not
    the only issue and a case can be made for the theory that a properly designed
    disk drive will wear out from heat and friction and dirt before it will
    suffer any electrical damage from being started and stopped once a day.
    I think that all the energy wasted by millions of PCs left on 128 hours a
    week when they are not being used is a bigger and more important issue than
    whether or not it will extend your repair cycle from 3 years to 5 years.
    There is also a small extra potential for a fire in a running device.

    I have been in the computer industry for close to 25 years, mostly as a
    technician. I have weighed all the arguments and I have decided to turn
    MY machines off when they will not be needed for 6 hours or more. I even
    turn the Xenix box off over the weekends.

    Like a lot of other things in modern life, this is not strictly a technical
    call but it has some moral undertones too. Make your own call but don't
    overlook part of the factors in the process.
    From: linderd@merrimack.edu (Doug Linder)
    Newsgroups: comp.sys.ibm.pc
    Subject: Re: Horizontal cards (was Re: Standing your box upright)
    Message-ID: <18991.262c5b5c@merrimack.edu>
    Date: 18 Apr 90 12:19:40 GMT

    In article <1990Apr16.181035.3017@seri.gov>, marshall@wind55.seri.gov (Marshall L. Buhl) writes:
    > Another thing to consider when standing a PC on end. One of my secretaries
    > stood hers on end for a year or so. When she left, I tore the machine
    > apart and found that the AST 6 Pack was really warped. If you laid it on
    > a table, one end would be 1" in the air. It still works, but...

    Maybe the solution is to flip the thing from end to end every 6 months to
    even out warpage? ;-)

    But seriously, folks, when I was a PC tech I did see some problems with this.
    Essentially, it seems that the larger the number of cards you have, how big the
    cards themselves are (height/thickness) and how good your fan is are the big
    factors. Remember, these cards are designed to stand on edge and let the heat
    float to the top of the box where it can be sucked away by the fan. A PC on
    its side screws up this system and the heat, trying to rise, gets caught by the
    cards and what you end up with are little heat sandwiches between the cards -
    the hot air has nowhere to go. I have seen machines with lots of big cards in
    them that you could fry an egg on. The biggest danger with cards "melting" is
    not only that the card itself may malfunction, but that it wil come in contact
    with something it shouldn't (usually another card, the one below it) and short
    out the whole works. I have seen motherboards die this way.

    This can be alleviated by some things such as:
    1) a fan (a standard room fan pointing at the machine),
    2) room A/C,
    3) simply leaving the cover off the machine and covering it with a cloth
    supported by a wire frame (to hold the cloth away from the machine a
    few inches)
    4) If the cards are long enough, mounting brackets at the front of the machine
    for the ends of long cards to rest in will prevent "drooping" at the ends
    but alas, cards still droop in the middle.

    My best advice: Unless you have only a monochrome card and a serial/parallel
    card, or some other very low heat/high circulation setup inside the machine,
    place it the way it was designed to be placed - "power users" take note. The
    equipment is too expensive and your time too valuable to waste with breakdowns.
    Would you want your PC to die in the middle of a presentation because the
    Video card just warped enough to touch the drive controller and short out the
    whole works? BTW, though, I have found that smart terminals like Novell
    network PCs work OK on end - as long as the novell card is about the only thing
    in the machine.

    Hope this helps.
    Douglas D. Linder linderd@merrimack.edu
    Merrimack College, N. Andover, MA {uunet,wang,ulowell}!samsung!hubdub!linderd
    From: alz@tc.fluke.COM (Al Weiss)
    Subject: Is it [orientation] harmful to disk drives?
    Date: 4 May 90

    Dunno about floppies. For hard drives it depends upon the manufacturer. All of
    the Seagate manuals I've seen, for instance, are VERY specific in their manuals
    about not elevating the front or back more than 5 degrees from horizontal.
    They can however be turned on their sides up to 90 degrees, but no further (ie
    not upside down). They should also be formatted in their permanent
    orientation. My understanding is that the head positioning mechanism gets worn
    out on an angle, and the motor bearings can't hack being upside down. On the
    phone, Seagate told me that they would not honor any warrantee if they know
    that it has exceeded those limits. I've heard some newer Seagates don't have
    limits, but don't know for sure, nor do I know about the CDC's. Conner,
    Quantum, Miniscribe, Maxtor(?), on the other hand, (of the ones I've seen)
    specifically say "any orientation".
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  2. #2
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    i think this is the wrong forum, because it is intended for original works.

    nice read all the same.
    Hmm...theres something a little peculiar here. Oh i see what it is! the sentence is talking about itself! do you see that? what do you mean? sentences can\'t talk! No, but they REFER to things, and this one refers directly-unambigeously-unmistakably-to the very sentence which it is!

  3. #3
    The Doctor Und3ertak3r's Avatar
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    Apr 2002

    Why not read the guidelines on posting in this section.. Before even posting here.. Certainly would save the hassell for the Moderators of moving your misplaced Threads..

    You seem to find some handy information, that a few or even many would like.. so be cool and you will be here for a long while..

    "Consumer technology now exceeds the average persons ability to comprehend how to use it..give up hope of them being able to understand how it works." - Me http://www.cybercrypt.co.nr

  4. #4
    Trumpet-Eared Gentoo Freak
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    I do agree this isn't the forum to put this, but it's some handy info. Nice collection.
    Come and check out our wargame-site @ http://www.rootcontest.org
    We chat @ irc.smdc-network.org #lobby

  5. #5
    Senior Member
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    Jan 2002
    I think a lot of this is irrelevant these days.

    Hard drives can be mounted any way up. Look at different cases - some have them upside down, others on the side.

    Totally agree with the guy who wrote about "Infant Mortality". When I was a sysadmin, nearly all the failures I saw were on brand new equipment, within 2 weeks.

    In my experience also, fan bearings wear out, which causes the fan to stop eventually and causes overheating. On most machines at least 4 years of continuous operation is required for this to happen.

    Dust also causes major problems for many machines left on for many years (assuming they don't run in a clean room).

  6. #6
    Just a Virtualized Geek MrLinus's Avatar
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    Moved from Tutorials to General Chit Chat.

    I also have to agree that it's a wee bit dated. Generally, anything from prior to 1998 will be dated at this point. The biggest issue I see with it being on all the time is the excessive heat. I had 3 in my bedroom for a while and the room went up an extra 5-7 degrees! (Heck, it was so warm, we never had to turn on the heat during some winters).
    Goodbye, Mittens (1992-2008). My pillow will be cold without your purring beside my head
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  7. #7
    Senior Member
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    Mar 2003
    heh, just stumbled on this thread and thought I would share a recent experience with a hard drive of mine.

    After I moved, about a year ago, I was setting up a "new" system using some left over parts that I had. I didn't have room for a second drive inside the case, so being a typical geek I just decided to leave the drive in the case, but unmounted and almost upright but leaning a bit because the cable was too short. Well it stayed like that until about 2 weeks ago when I FINALLY bought a new case to correct this problem, yes I'm lazy

    Well I mounted the drive like it should have been mounted (flat) and it just would NOT spin up. It had been working perfectly fine with no signs of failure. I took it out, I checked connections, I did all sort of troubleshooting on it. BTW, it was a secondary drive (d: primary partition) on a Win2k server I was messing with. Well I mounted it back in, flat once again, and decided to try again. The BIOS recognized the drive and I could hear it spin. I decided to let win2k attempt to boot up... and it just sat there. It hung for a LONG time, and because I could hear the drive spinning and could see the progress bar on win2k still moving I decided to let it sit for a while and see if it would "fix" itself. I think I let it sit for about 2 hours before finally giving up on it. I reached in to remove the drive and it was SCALDING hot! Well that was strange, considering I have never been literally burned by a hard drive before, so I let it cool down before trying to remove it again. Then inspiration struck me. After the drive had cooled down I removed it from the mounting and replicated the way the drive used to be in the old case, almost standing straight up on it's end and slightly leaning. Funny thing is once I did that the drive worked fine, and still does. Heh, mount it flat and it won't work and gets EXTREMELY hot, mount it the lazy half-assed way I had it before and it works fine. Go figure.

    I have no idea if it has anything to do with that last portion of the original post or not. Just thought it was relative in some way

    FWIW I didn't care if I lost that drive or not... it's an old drive that was just sitting around that I thought I would use.

    Give a man a match and he will be warm for a while, light him on fire and he will be warm for the rest of his life.

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