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 isn’t 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. . .