Thread: Hybrid hard drives

A hybrid hard drive is a hard drive whose primary data storage technique uses the normal heads and platters, but also has a rather large flash memory component. The hard drive puts recently used/often used data in the flash storage area because seek times on a flash drive are ~0ms. When a read is requested from the harddrive, it looks for the data both on the flash and the platters. You're hope is that it's on the flash (there are some advance caching techniques it can use to give you about a 60% hit ratio).

Another benefit of hybrid drives is that when accessing flash memory, they require very little power. This is great news for notebook owners (a flash hard drive can give a laptop a 10% - 20% increase in battery life).

I think the OP is a little confused about this. Flash is non-volatile memory, so there is no memory loss on power-down. Anything stored in flash is stored.

That being said. Often times filesystems do store data in memory (RAM) and have algorithms to determine the best time to send that data to the DMA so as not to interrupt any current processing. This is known as flushing the IO buffer (you can actually flush many buffers such as network, etc...). If your system is powered down before or during an IO flush, that is when dataloss can happen.

The solution to minimize this is to treat the drive as removable storage (if your OS supports this). This increases the number and priority of flushes, as the OS is informed that this drive can and will be removed from the system often. Most OSes provide a setting for this.