Sometimes I face the problems with my video card, so the system freezes. Reset button is broken, so the only way is to hold down power button for 5 secs. Guess that this action differs from power loss, cause motherboard controls process of poweroff, it may send some signals to hw, before shut down.
I am worried about my hard disk drives. Will the hard disk drives heads be safely parked or I will get +1 bad event to SMART? Or it motherboard-dependent?
Modern hard drives are designed to use the rotational energy in the spindle to quickly park the heads on a power failure. This is rougher than a graceful shutdown as you can typically hear the hard drive click relatively hard on a hard shutdown. As such, this process can cause accelerated wear, but should not be a cause for concern unless done very frequently. There is a SMART attribute for this, "Power-Off Retract Count", which is incremented when this happens, but it is not a pre-fail attribute.
Although hardware damage should not occur, data loss is still possible. If writing is in progress, the hard drive will finish writing the current sector before retracting to the parking area so that sectors are never corrupted as a direct result of power failure. However, because data that has recently been sent to the drive may not have been committed to the platters (they are briefly held in the onboard cache for performance), that data may be lost on a power failure.
The read/write heads of a mechanical hard drive float on a cushion of air only nanometers above the surface of the platters. In modern drives there is one head for each magnetic platter surface on the spindle, mounted on a common arm. An actuator arm moves the heads on an arc (roughly radially) across the platters as they spin, allowing each head to access almost the entire surface of the platter as it spins. The arm is moved using a voice coil actuator or in some older designs a stepper motor.
Modern rotary or swing arm voice coil actuators immediately park the heads in a safe position upon loss of power before the platters even have a chance to lose much rotational speed and therefore the air cushion the heads float upon. So no, your drives should not be affected but nevertheless you should definitely fix the underlying issue that is causing such frequent freezing and necessitating repeated resets.
Hard drives today are very robust. Removing power from them should not result in damaged hard drives. However, it is very possible that if data isnt flushed from the OS or hard drive buffers, that data can be lost.
