Solid State Drive (SSD)
A Solid State Drive (SSD), in its simplest form, is a drive (disk) emulator, that uses solid state devices (memory) to store the data instead of using rotating magnetic platters. The memory used today could be volatile but it is backed up by a battery-based power system, or it could be flash RAM, that does not loose the data when power is removed.
Believe it or not, this is not a new technology. Way back in the mid 1980’s, when I was working for an automatic test equipment (ATE) company, they designed and made a RAM Disk for a few select customers that needed to have faster load times of the data patterns that were used to test integrated circuits. This was because the hard disks of that day were very slow when it comes to access time, usually in the hundreds of milliseconds.
Pros and Cons of Solid State Drives
The major benefit of solid state drives is speed. This is because these drives eliminate the physical pieces of a hard disk that cause access delays. When you read or write a block of data, the platter has to rotate into a position where that data block can be accessed, which takes time. The actuator arm may also have to move the head across the platter, and that takes time too. So any of these physical movements that can be removed will speed up the system.
There are a few other things that make solid state drives a good thing. Since there is no physical pieces to move around, solid state drives are less susceptible to vibration in a computer system or storage array. They are also less susceptible to changes in temperature. A standard disk drive has to recalibrate internally whenever there is a temperature change of just a few percentage points. That is no longer needed with SSD.
Speaking of power, solid state drives require less power than conventional disks, therefore making them part of the “Green Computing” or “Green Storage” movement happening today.
Now for the cons of SSD. Cost is the biggest obstacle of using solid state disks. But as the market evolves and they become more available to the general public, the price should come down. Capacity is the other weak point of solid state drives. To make a really big, really fast memory system is not that hard, but to make it fit into a form factor similar to what it is replacing, such as a 2.5 or 3.5 inch hard disk, then it becomes a challenge.