What is an SSD – Solid State Drive And Why Need It
There are many reasons why you need a SSD aka solid state drive, but some background on computer drives.
Computer Drives
Mechanical drives have been used in computers for many years and were first introduced in 1956 by IBM (International Business Machines). Mechanical drives or electro-mechanical data storage device uses magnetic storage to store and retrieve digital data using rapidly rotating platters coated with magnetic material. Magnetic heads located on a moving actuator arm reads or writes data to the platter surfaces. Data is accessed in a random access manner which means unlike a tape drive data can be accessed randomly depending on the data block location. With a tape drive access is sequential or linear. This storage is unlike RAM (Random Access Memory) whereby the data is non- volatile. RAM data is lost when power is stopped.
Today many computer manufacturers and system builders will include an SSD and possibly a mechanical in their computers. The SSD is generally smaller and is the boot drive which includes the Operating System and the mechanical which is larger is intended for data storage.
SSD’s Are Faster And More Reliable
There are several SSD manufacturers as the technology has been available for many years with the first one commercially available and shipped by SunDisk in 1991. In 1998 SanDisk introduced SSD’s in 2.5” and 3.5” form factors with PATA (Parallel Advanced Technology Attachment). One reason why you need an SSD is that today’s SSDs are reliable and becoming cheaper each year. They are faster than mechanical drives by a factor of approximately 5.
Modern SSDs store data in NAND flash memory cells (NAND = Not AND logic gate) and flash is non-volatile solid state memory (non-volatile meaning it won’t disappear when the power is turned off). The problem with Flash memory is that it has a limited number of program or erase cycles – known as P/E cycles. These cycles vary between different SSD drives and manufacturers being between 500 and 100,00 cycles. Modern SSDs, such Samsung use V-NAND technology developed by them using 48 layers of memory cells
Over Provisioning
SSD’s use Wear-levelling which evens out the P/E cycle flash cell use, this evens out the wear as flash memory cells need to be erased in blocks which means data has to be constantly moved around. So SSDs wear out faster the less free memory they have available. Therefore leaving at least 10% free space on an SSD will increase its life, this is known as “over provisioning” and is done in hardware by some SSDs.
Most SSD manufacturers provide a rating of endurance by giving the amount of data which can be written before a drive fails. This can be expressed as TBW = Terabytes written or PBW = petabytes written or DWPD = Drive Writes Per Day. The larger the drive the greater the values.
Higher Life Expectancy
SSDs are getting better and better as well as cheaper. Their life expectancy is getting higher and now they are more than likely to outlast the computer system they are installed in. Mechanical drives will sooner rather than later be extinct like the dinosaurs as more computer manufacturers install them as the default storage item.
Backup, Backup, Backup!
As with all of your data we recommend frequent backups to another backup medium be it a mechanical device, an SSD device or “the cloud”.
If you have any data issues, then please contact us here at Affordable Computer Repairs and Service and we can assist you.
FHI If you have not backed up and your hard drive has failed we offer an affordable data recovery service.
