Hard Drive Failure Modes
Hard disk drives are mechanical devices and are susceptible to damage from physical shock. One type of physical shock, called operating shock, occurs when the disk is in operation. During operation, the drive head is typically over the drive platters reading and writing data. When a physical shock to the drive occurs during operation, the head and the platters can come into contact causing both components to be damaged.
The second type of shock, called non-operating shock, occurs when the head is in the unloaded position, or not positioned over the platters. When a physical shock occurs in the non-operating state, the head can contact the ramp it is positioned over and damage the ability of the head to read and write data to the hard disk drive. All devices with hard drives are subject to damage from operating and non-operating shock.
The mechanical construction of the 7-Series recorders is designed to minimize the transmission of shock to the hard drive. The drive is isolated from the chassis using special shock-reducing closed-cell foam. This material increases the amount of shock the hard drive can withstand. Additional protection can be achieved by operating the unit in a carry case.
If the recorder is used in applications subject to extreme motion, Sound Devices recommends recording to CompactFlash only. The hard drive will park its write heads to reduce the chance of failure.
With all electrical devices, the higher the ambient temperature the shorter the device’s operational life. Therefore, take care to observe the specified temperature rating.
There is also a risk from sudden temperature changes, which can create condensation inside the drive. This condensation can lead to the drive’s read/write heads adhering to the disk surfaces which will, in turn, stop the hard disk from rotating. Condensation tends to occur when the temperature inside the drive suddenly falls, for example, just after the unit is moved to a new location, or after operation is stopped in a cold environment.
Sudden changes in temperature or air pressure can cause disk surface material to evaporate, which can also cause the head to adhere to the disk surface. This can happen when a hard disk drive is left unused for a long period of time.