HDD and SSD are two types of devices used for data storage. HDD (Hard Disk Drive) is an electromechanical device with internal moving parts, while SSD (Solid-state Drive) stores data in memory chips. Both HDD and SSD use the same interface, therefore they are easily replaceable with each other. HDD are the most popular storage devices used as secondary storage in personal computers. SSD are mostly used for mission critical applications.

What is SSD?

SSD is a device used for data storage. It stores persistent data using a solid-state memory. SSD stores data in non-volatile microchips. SSD do not contain any moving parts inside them. Because of these features, SSD are not vulnerable to physical shock, produces less noise and takes less time to access. But, they are slightly expensive and the number of writes per life time could be limited. Most SSD are either DRAM-based or flash memory based devices. SSD are used in applications such as mission critical applications, equity trading applications, telecommunication applications and video streaming, which benefit greatly from faster access times.

What is HDD?

 SHDD is a type of storage media used in computers. It is the most popular device used for secondary storage in personal computers. Data in a HDD is retained even without the power because of its non-volatile nature. Also, data could be accessed randomly in a HDD. Data is read/written magnetically by the heads of the HDD. HDD was introduced by IBM in 1956. Initially, hard disks were very small in capacity and very high in price, but as the time went by, the cost has gone down dramatically, while the capacity has become very large. SATA (serial ATA) sand SAS (serial attachedCSI) are two of the high-speed interfaces used by HDD today.

What is the difference between SSD and HDD?

Because SSD do not have internal moving parts like HDD, SSD sign-up is relatively faster than HDD. SSD register is almost instantaneous, but HDD can take several seconds to register Similarly, the data access time is relatively several times smaller than in HDD (0.1 ms vs. 5-10 ms), because SSD access memory directly from the flash memory, while HDD has to move heads and rotate the disks to access data. Unlike HDD, read performance is consistent in SSD. HDD require defragmentation after some time, but SSD do not necessarily gain anything from defragmenting.

SSD are quite, but HDD may make some amount of noise (due to moving parts) depending on the model. Unlike HDD, SSD are not susceptible to physical damage due to the lack of moving parts. Therefore, considerable care should be taken to make sure to avoid physical shock, vibration or even altitude changes when using HDD. Data on a HDD are susceptible to magnetic surges. Typically, SSD are lighter than HDD. SSD that use flash memory have a restriction on the number of writes per life time, but HDD do not have this limitation. When it comes to price/cost, HDD are always less expensive (per GB) than SSD. Furthermore, HDD consumes few times more power than SSD.