This weeks article is from the ARS Technica website and is titled "Solid-state revolution: in-depth on how SSDs really work" (Lee Hutchinson - Jun 4, 2012). In it, Mr Hutchinson discusses Solid State Drive (SSD) technology and how it can make a computer subjectively faster by replacing tradition "spinning platter" disk drives.
SSDs are basically a storage device that replaces spinning metal disk/platters commonly found in traditional hard drive mechanisms with non-volatile NAND flash memory, which allows SSDs to function at much higher speeds by reducing the latency time of read/write operations. NAND flash memory is the same technology found in cell phones and USB "Thumb" drives. The author provides a very detailed description of exactly what NAND memory is and how it functions.
Interestingly, SSDs have one big shortcoming: they can only be used for a finite number of writes. Over time, the process used by SSDs to free up previously used space for new write operations slowly degrades the functionality of the SSD, slowing down the write times, until eventually it enters into a read-only condition where data can no longer be written to the disk. Manufacturers use controllers to attempt to manage the degradation and prolong the writable life of the SSD as much as possible.
The author then progresses through various methods used by SSD manufactures to prolong the usable life of SSDs, before moving on to Write Amplification, which refers to the logical amount of data written to the SSD versus the actual amount of data written to the SSD, and wear leveling, which refers to how write operations are spread across all of the flash cells in order to keep their use evenly distributed across all of them.
Finally the author goes into the popularity of SSDs, specially in data center operations where high I/O applications benefit from the low latency of read/write operations to/from SSD drives, as opposed to other well established technologies such as Fiber Channel attached drives and Serial Attached SCSI (SAS) drives. SSDs tend to be more expensive per megabyte, but prove to be exponentially better because of their speed.
Personally, I have an old Apple MacBook Pro (from 2012) that originally came with a SATA drive installed. Replacing that drive with a SSD effectively gave the laptop a new lease on life and since MacOS was able to read/write to/from it's operating system drive a lot faster, everyday operations became effectively faster, and made the old MacBook usable.
Lee Hutchinson - Jun 4, 2012 3:30 pm UTC. (2012). Retrieved from https://arstechnica.com/information-technology/2012/06/inside-the-ssd-revolution-how-solid-state-disks-really-work/
