The SSD Vs. a Hard Drive
An essential part of every computer, a hard drive stores everything from your personal files to the computer's operating system. Known as a non-volatile form of data storage, this means that the hard drive retains its information even once the computer's power shuts off. Traditional hard drives have served computers and laptops for decades but recently a new competitor, the solid state hard drive, or SSD, has arrived on the market.
A hard drive exists within a sealed metal container meant to protect inner magnetized components. It also contains an electrical motor, read/write heads and a platter. These parts all work together to read and write information from the platter. The hard drive processes commands from the computer for data and uses the motor to turn the platter to the appropriate location while the read/write heads carry out the computer's initial command. The hard drive also contains a physical allocation file, which charts out locations for new files and keeps records of the locations of existing files.
Solid State Hard Drives
While an SSD fills the same tasks of reading and writing data, it functions in a vastly different manner. Utilizing no moving parts at all, an SSD instead employs various chips with flash memory, another form of non-volatile memory, to store data. The drive records information through its flash cells, utilizing electric charges to store data. It holds that data indefinitely until another electric charge erases it. Unlike traditional hard drives, a computer can't simply overwrite old data and must erase it in chunks.
Speed remains the SSD's greatest advantage over traditional hard drives, sometimes to the magnitude of 100 times faster. Because an SSD uses no moving parts, it runs quieter than a traditional hard drive and due to less internal friction, it runs cooler as well. An SSD also resists damage from shock, such as a drop, better than a traditional hard drive. Hard drives still perform some tasks better than SSDs, however. Hard drives handle small files much faster than SSDs, which manage memory in larger chunks. Flash memory also tends to wear out over a period of time as its cells get overwhelmed by the write/erase/rewrite process. When cared for and kept from physical shock, hard drives may last a very long time.
In perhaps its single greatest strike, an SSD costs much more than a traditional hard drive for the same memory capacity, causing many to resist transitioning to the newer technology. Both kinds of drives tend to have an average cost per gigabyte of capacity. While these prices have slowly decreased, both models have experienced equal drops which has not solved the price gap problem. Casual Internet browsers and other light computer users won't benefit from an SSD as dramatically as those who use graphic-intensive and application-heavy systems, making the additional cost a dealbreaker.
References & Resources
- Florida State University; How a Hard Drive Works; Michael Davidson
- Smithsonian Institute: Flash Memory Technology
- Georgia Southern University: Solid State Hard Drives (SSD) Vs. Traditional Hard Drives (HDD)
- Penn State University; Solid-State Drives; Joshua Dionis; April 2009
- "Computer World"; Review: Hard Disk vs. Solid-State Drive-- Is an SSD Worth the Money?; Lucas Mearian; June 2009