Computer Corner #18
By Bob Habas
Formally of computer Connections

Solid State Drives

A solid-state drive (SSD) is a data storage device that uses solid-state memory to store persistent data. An SSD emulates a hard disk drive interface, thus easily replacing it in most applications.

Open casing of 2.5-inch traditional hard disk drive (left) and solid-state drive (right).


  • Faster start-up because no spin-up is required.
  • Fast random access because there is no read/write head, resulting in faster boot and application launch times.
  • Consistent read performance because physical location of data is irrelevant for SSDs.
  • File fragmentation has negligible effect.
  • Silent operation due to the lack of moving parts.
  • Low capacity flash SSDs have a low power consumption and generate little heat when in use. This contributes to long notebook battery runtimes.
  • High mechanical reliability, as the lack of moving parts almost eliminates the risk of "mechanical" failure.
  • Ability to endure extreme shock, high altitude, vibration and extremes of temperature. This makes SSDs useful for laptops, mobile computers, and devices that operate in extreme conditions.
  • Failures occur less frequently while writing/erasing data, which means there is a lower chance of irrecoverable data damage.
  • SSDs are more expensive per gigabyte than hard drives. Whereas a normal flash drive is between $1.50 - $3.45 per gigabyte, hard drives are around $0.38 per gigabyte.
  • The capacity of SSDs is currently lower than that of hard drives. However, flash SSD capacity is predicted to increase rapidly, with drives of 1 TB already released for enterprise and industrial applications.
  • SSDs currently have a much slower write performance compared to their read performance.
  • Due to the low storage density of SSDs, hard disks can store more data per unit volume than DRAM or flash SSDs, except for very low capacity/small devices.
  • Flash-memory cells have limited lifetimes and will often wear out after 1,000 to 10,000 write cycles for MLC (multi-level cell), and up to 100,000 write cycles for SLC (single-level cell). As a result, the performance of SSDs degrades with use.
Do I need to defrag SSD or other flash drives?

No. Unlike a traditional hard disk drive, a Solid-State Drive (SSD), jump drive, flash drive, and thumb drive have no moving parts. Which means even if you were to defragment the drive it wouldn't increase the performance of the drive. Defragging a drive is designed to arrange the data on the drive so the access arm can get to it quicker and read it in one section of the drive instead of having to move to multiple portions of the drive.
  • PQI 2.5" 32GB SATA Internal SSD: $99.99
  • Patriot 2.5" 64GB PCIe Internal SSD: $149.00
  • Kingston 2.5" 128GB SATA II SSD: $245.00

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