Announcement

Collapse
No announcement yet.

Hard drive shock / vibration thoughts

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Hard drive shock / vibration thoughts

    The whole issue of hard drive failure must be broken down into the facts. Working with cars and airplanes with a few years has allowed me to gain some kind of knowledge in this field. There are two components we should be talking about when trying to protect a hard drive in a car. These are shock (half sine wave) and vibration (full sine wave). Shock occurs when a hard drive encounters acceleration and a sudden stop. Vibration is a continuous acceleration and deceleration oscillating from one direction to the other. To prevent damage from shock, increasing the mass of the hard drive by mounting it directly to the chassis of the car is a great idea. However, this does not help the vibration problem and will probably worsen it. So, what is really needed is a firm mount that accelerates with the chassis of the car when it encounters shock, but not so firm that it transmits the vibration inherent in any car to the hard drive. Some believe that going over pot holes only causes shock to occur. This is not true. Shock is the most significant force resulting from this. However, a noticeable amount of vibration can result. Listen to your car the next time it goes over a pothole. The clunk clunk sound you hear is shock. The rattle rattle sound you hear is vibration.

    As far as the orientation of the hard drive is concerned. There are pros and cons to each. Mounting vertically keeps the heads from smashing into the platters, but may allow the heads to smash into the walls of the hard drive enclosure and read incorrect data. Gravity isnt a factor at all in this because most hard drives are designed to be mounted either horizontally or vertically. Mounting the hard drive horizontally makes the head prone to smashing into the platter upon any kind of shock. However, this does keep the head from being moved by shock.

    Vibration affects hard drives the same regardless of orientation. The direction of vibration varies significantly from car to car and situation to situation. This is caused by different speeds, cars, and road conditions. Because of this, only shock can be considered in the orientation argument, because it is the only constant factor with regard to direction.


    So, excessive shock may cause read errors when mounted vertically causing a system crash. You restart the computer and everything is ok

    But mounting horizontally will crash the hard drive. You try to restart the computer and it freezes / gives you errors and you have to buy a new hard drive.


    Now that we know exactly what we are trying to dampen, maybe someone can come up with a design that does this best. IMHO a silicon or rubber dampener seems to be the best solution. Like the one found in the link below I use visco elastic foam (memory foam) on mine. It works well, but I do have a heat problem. This sort of deisgn would allow for better heat dissipation.

    http://www.mp3car.com/vbulletin/show...rive+vibration

    A rigid design that allows the hard drive to take on the mass of the car when experiencing shock, but not so rigid that it transfers too much vibration.

    Hopefully I inspired someone somehow by writing this. . .
    ________________________________________________
    Worklog
    K7VTA3
    1500+ Athlon 4 Mobile
    510mb PC3200 DDR
    ATI Radeon 7000 64mb
    [||||||||||] 95% Complete

    RentATechnow.com

  • #2
    I've had a maxtor 80gig hard drive sitting in a case tied down to the floor of the back of my wagon for more than a year and i haven't had a skip yet.. not one.. am i lucky? it's a normal 3.5 hard drive..

    i also have sports suspension lowered over 1" all around so this will make the ride even bumpier.. In addtion I have 18" rims..
    CAR INFO HERE
    "He who dies with the most toys, wins".

    Comment


    • #3
      130,000+ miles in a 4x4 and no problems
      2001 S10 ZR2

      Chucks Skin - to old

      Comment


      • #4
        5 months in a Shuttle SFF box Sitting right in front of the Subwoofer enclosure. Not a hiccup.

        I still think this whole platters crashing vibrations messing rotation with car direction is a bunch of myth hoopla.

        Comment


        • #5
          Originally posted by koolaidkitten
          I still think this whole platters crashing vibrations messing rotation with car direction is a bunch of myth hoopla.
          Agreed.

          There seems to be no pattern between orientation and damage to harddrives. I think all of the self-professed harddrive experts should shut the f**k up.

          The only people that actually know the answers to these questions are the engineers that design and build the harddrives.

          Comment


          • #6
            Chuck: How are your drives mounted - vertically or horizontally? (not immediately clear from the pic)

            Comment


            • #7
              Shock ratings are 200-400 Gs for normal hard drives and 800-1200 Gs for 2.5" hard drives.

              Is there any evidence that this isn't sufficient for normal (and even abnormal) operation in a vehicle?

              Comment


              • #8
                Originally posted by ktritz
                Shock ratings are 200-400 Gs for normal hard drives and 800-1200 Gs for 2.5" hard drives.

                Is there any evidence that this isn't sufficient for normal (and even abnormal) operation in a vehicle?
                Aren't those ratings for a powered down drive though?

                I thought a powered up drives ratings were usually below 200.

                Comment


                • #9
                  My 3.5" is mounted vertically in a piece for hard-foam, in which I have cut a hole just a bit smaller than the disk (so that it will sit very tight), but I have only lowered it approx half into the foam, so that it will not overheat.
                  /SOS/
                  XP Pro, CF 2.0-newest| Pioneer HU with 7" flip-out (EQ, Surround)
                  Epia V10000 + nVidia FX5200, Opus 150w, 7" Lilliput, DVD* SlotIn, Wavelan, Bluetooth, GPS, WebCams, DVB-T

                  Comment


                  • #10
                    Originally posted by rubicon
                    Chuck: How are your drives mounted - vertically or horizontally? (not immediately clear from the pic)
                    It is on a 45-degree angle and the front of the drive is facing to the right with the ribbon cable coming out of the rear left.
                    2001 S10 ZR2

                    Chucks Skin - to old

                    Comment


                    • #11
                      d'oh! I see it now. Are you using bungee cords to mount it like that?

                      Comment


                      • #12
                        I think some of the specs that are given in this thread are a bit bogus. Here are the specs for an IBM 120GB 7200RPM DESKSTAR.

                        Environmental Parameters
                        Min Operating Temperature : 5 C
                        Max Operating Temperature : 55 C
                        Humidity Range Operating : 8 - 90%
                        Shock Tolerance : 55 g @ 2ms half-sine pulse (operating) / 350 g @ 2ms half-sine pulse (non-operating)
                        Vibration Tolerance : 0.67 g @ RMS (random) (operating) / 1.04 g @ RMS (random) (non-operating)
                        Sound Emission : 31 dB

                        http://www.memorysuppliers.com/ibm1272desid.html


                        So, 55g OPERATING 350g NON OPERATING for shock.

                        So, data shows orientation of the hard drive may not be a significant factor as it can take 60Gs of shock without failure presumably in any orientation. Getting a hard drive to experience 60Gs of shock when mounted to a 2500 pound car is a feat. The accident that caused Princess Diana's death was 70Gs. So, I eat my words, happy? However, it is only because of the weight of the car that the force was 70Gs. A hard drive which weighs say, one pound, dropped from one foot would experience far more force than this. Thus anchoring the hard drive to the car firmly is imperative.


                        Vibration tolerance is only 0.67g OPERATING and 1.04g NON OPERATING.

                        This shows that vibration IS a significant factor. Cases where people are mounting their hard drives rigidly to their car without failure may not be experiencing much vibration. However, this is definitely something the hard drives are prone to failure from.

                        So like I said before, mount your hard drives in a mount that is rigid enough to take on the mass of the car, but not so rigid that it transfers vibration. This gives the hard drive the greatest possible chance of survival in any condition.
                        ________________________________________________
                        Worklog
                        K7VTA3
                        1500+ Athlon 4 Mobile
                        510mb PC3200 DDR
                        ATI Radeon 7000 64mb
                        [||||||||||] 95% Complete

                        RentATechnow.com

                        Comment


                        • #13
                          This is not exactly what you are looking for, but It shows a dampening concept that I have found to work quite well. I use it in my motorhome, which is verry vibration prone going down the road.
                          I think with some creativity, this concept could be adapted for harddrive suspension.
                          Just need to build an appropriate frame work
                          Attached Files

                          Comment


                          • #14
                            Wow, oldschool. But if it works..!

                            Comment


                            • #15
                              I say buy an 1:10 scale rc car and mount the hard drive into the car. That way you can have 2 suspensions, your car's and the rc vehicle's. Crazy, but it should work .think about it.
                              Iwill ZPCgx 2.4ghz cel, 256mb pc2700, external combo drive, 80gb 2.5 laptop drive, xp pro, usb gps, 7 in Lilliput TS , carnetix CNX1900. All mounted ghetto- still experimenting and tweaking.

                              Comment

                              Working...
                              X