Standard Hard Disk Drives (HDDs) contain one or multiple disks called platters, which are covered in a magnetic coating and then rotated at high speed. Drive heads then move across the platters, changing the magnetization of the material beneath to record data, or reading its state to return the stored information. Solid State Drives (SSDs) by comparison feature a non-mechanical design of NAND flash mounted on circuit boards and contain no moving parts. Rotating media drives have adequate shock and vibration specs but nowhere near SSDs which are shock resistant up to 1500g/0.5ms. The design difference dictates the benefits and drawbacks of each.
Hard Disk Drives vs. Solid State Drives
Hard Drive vs. SSD
HDDs consist of various moving parts such as spinning platters and the read/write heads making them susceptible to shock and damage in rugged environments. The typical failure mode is the read/write head bangs into the platter damaging the magnetic media. Some drives will detect shock events and park the heads but there is still a relatively low limit to the vibration and shock these drives will sustain. In addition, in a high vibration environment, even though the drive is not being damaged when the heads are parked, neither is the drive able to access the data because the heads are parked.
Because SSD’s have no moving parts, they are as immune to shock and vibration events as any of the other electrical components in a system and are no longer the limiting factor in total system susceptibility and reliability.
SSDs can have (100x) greater performance than traditional “rotating-media” hard drives. That greater performance equates into almost instantaneous data access, quicker boot ups, faster file transfers, and an overall faster computing experience than rotating media drives. This incredible speed difference is due to a much shorter access time (less than a millisecond for an SSD compared to 17 – 18ms for an HDD).
SSDs use significantly less power at peak load than hard drives, less than 2W versus 6W for an HDD. Their energy efficiency can deliver reduced power consumption that translates into less power strain on system itself and a cooler computing environment.
Flash-based SSDs weigh considerably less than hard drives – only 77g versus 752.5g for an HDD. For military and industrial applications the weight savings when using multiple hard drives is significant.
SSD Disadvantages
Though still a higher price/gigabyte than rotating media hard drives (HDDs), SSDs offer cost savings in the long run for projects in the form of with lower energy usage and greater productivity with higher input/outputs Operations per Second (IOPS). One SSD can deliver the performance of 100 HDDs. In 2009, SSDs cost around $3 per gigabyte; today (2013) the cost is now down to $1 per gigabyte.
Another disadvantage of SSDs is that each flash memory cell on an SSD can endure only so many write cycles. This means that if you subject your SSD to heavy use, its data retention will be shorter than with conventional HDD. Luckily, SSD manufacturers are doing all they can to maximize SSD lifetime. They implement various firmware schemes to load-level SSDs and use TRIM technology to maximize the life of a solid-state drive.
Hybrid Solutions
Many of our customers are using a combination of SSDs and traditional hard drives where the operating system runs from the SSD for the speed advantage and the hard drives are used for data storage because of the low cost per byte.
So It Depends on Your Application…
If your application requires a system to be rugged, low power and light weight a solid state hard drive is the perfect storage device for your application.
CP Technologies offers rugged systems configured exactly to customer requirements including the appropriate selection of rotating media or SSDs.