Solid state drive and hard disk drive

SOLID STATE DRIVE

SSD stands for Solid State Drive. You’re probably familiar with USB memory sticks - SSD can be thought of as an oversized and more sophisticated version of the humble USB memory stick. Like a memory stick, there are no moving parts to an SSD. Rather, information is stored in microchips. A typical SSD uses what is called NAND-based flash memory. This is a non-volatile type of memory. What does non-volatile mean you ask? The simple answer is that you can turn off the disk and it won’t “forget” what was stored on it. This is of course an essential characteristic of any type of permanent memory.SSD does not have a mechanical arm to read and write data, it instead relies on an embedded processor (or “brain”) called a controller to perform a bunch of operations related to reading and writing data. The controller is a very important factor in determining the speed of the SSD. Decisions it makes related to how to store, retrieve, cache and clean up data can determine the overall speed of the drive. The technology is encased inside either a plastic or metal case and looks like nothing more than what a battery

HARD DISK DRIVE

HDD stands for a hard disk drive. An HDD uses magnetism to store data on a  rotating platter. A read/write head floats above the spinning platter reading and writing data. The faster the platter spins, the faster an HDD can perform.
 Typical laptop drives today spin at either 5400 RPM (Revolutions per Minute) or 7200RPM, though some server-based platters spin at up to 15,000 RPM!
The major advantage of an HDD is that it is capable of storing lots of data cheaply. These days, 1 TeraByte (1,024 gigabytes) of storage is not unusual for a laptop hard drive, and the density continues to grow. However, the cost per gigabyte is hard to calculate nowadays since there are so many classes to consider, though it is safe to say that all HDDs are substantially cheaper than SSDs.
When it comes to appearance, HDDs essentially look the same from the outside as SSDs. HDDs predominantly use the SATA interface. The most common size for laptop hard drives is the 2.5” form factor while a larger 3.5” form factor is used in desktop computers. The larger size allows for more platters inside and thus more storage capacity. Some desktop hard drives can store up to 4TB of data! Below is an example of what an HDD looks:

Comparison between SSD and HDD 

Attribute	SSD (Solid State Drive)	HDD (Hard Disk Drive)
Power Draw / Battery Life	Less power draw, averages 2 – 3 watts, resulting in 30+ minute battery boost	More power draw averages 6 – 7 watts and therefore uses more battery
Cost	Expensive, roughly $0.50 per gigabyte (based on buying a 1TB drive)	Only around $0.15 per gigabyte, very cheap (buying a 4TB model)
Capacity	Typically not larger than 512GB for notebook size drives; 1TB max for desktops	Typically around 500GB and 2TB maximum for notebook size drives; 4TB max for desktops
Operating System Boot-Time	Around 22 seconds average bootup time	Around 40 seconds average bootup time
Noise	There are no moving parts and as such no sound	Audible clicks and spinning can be heard
Vibration	No vibration as there are no moving parts	The spinning of the platters can sometimes result in vibration
Heat Produced	Lower power draw and no moving parts so little heat is produced	HDD doesn’t produce much heat, but it will have a measurable amount more heat than an SSD due to moving parts and higher power draw
Failure Rate	Meantime between failure rate of 2.0 million hours	Meantime between failure rate of 1.5 million hours
File Copy / Write Speed	Generally above 200 MB/s and up to 550 MB/s for cutting edge drives	The range can be anywhere from 50 – 120MB / s
Encryption	Full Disk Encryption (FDE)Supported on some models	Full Disk Encryption (FDE) Supported on some models
File Opening Speed	Up to 30% faster than HDD	Slower than SSD
Magnetism Affected?	An SSD is safe from any effects of magnetism	Magnets can erase data