evolution process
Since the birth of computers, storage devices have played an indispensable role. The first hard drives, like the famous IBM RAMAC, were big, heavy things, and it wasn’t until around 1980 that IBM introduced thin-film heads that we got rid of those behemoths. Then we started to focus more and more on memory density and speed, not forgetting the idea of being smaller and more convenient. However, due to the innate design of the mechanical hard disks, we have to face many problems such as the stability and earthquake resistance of its mechanical parts. In recent years, a new form of storage device began to emerge, that is, solid-state disk (SSD), it with a variety of superior performance relative to the mechanical hard disk has become a new star in the hard disk industry, because there are some controversies, it also failed to shake the mainstream status of mechanical hard disk in a short time.
Comparison of HDD and ssd from working principles
➡️How a mechanical hard disk works
An HDD is a non-volatile storage device on a computer that uses a Hard, rotating Disk. It stores and retrieves digital data on a flat magnetic surface. The information is written to the Disk by an electromagnetic current that changes the polarity of the magnetic head close to the magnetic surface. At the same time, information can be read in the opposite way, such as when the reading head passes over the recording data and the magnetic field causes the electrical signal in the coil to change. Its read and write adopt random access, so data can be read in any order. The mechanical hard disk consists of one to several high-speed disks and a magnetic head mounted on the actuator cantilever. According to the principle of implementation, it is not hard to find that modern mechanical hard disks work as the name suggests, by mechanical means. Electric motors drive the disk at high speed, and magnetic heads operate to access data.
➡️How an SSD works
A Solid State Disk (SSD), is a computer storage device that uses memory as permanent storage. Although SSDS no longer use “disks” to store data, nor do they have motors for “drives,” they are still referred to as solid-state disks or solid-state drives, according to naming conventions. Solid-state drives are volatile and non-volatile. Here we focus on non-volatile solid-state drives that are more suitable as alternatives to traditional hard drives. Data access in non-volatile SOLID-state disk is mainly realized by NAND Flash and its master chip. There is no moving mechanical part, and it is a pure chip structure.
Advantages and disadvantages
| Attribute | SSD (Solid State Drive) | HDD (Hard Disk Drive) |
| Power Draw / Battery Life | Less power draw, averages 2-3 watts, resulting in 30+ minute battery boost | More power draw averages 6 – 7 watts and therefore uses more battery |
| Cost | Expensive, roughly $0.50 per gigabyte (based on buying a 1TB drive) | Only around $0.15 per gigabyte, very cheap (buying a 4TB model) |
| Capacity | Typically not larger than 512GB for notebook size drives; 1TB max for desktops | Typically around 500GB and 2TB maximum for notebook size drives; 4TB max for desktops |
| Operating System Boot Time | Around 22 seconds average bootup time | Around 40 seconds average bootup time |
| Noise | There are no moving parts and as such no sound | Audible clicks and spinning can be heard |
| Vibration | No vibration as there are no moving parts | The spinning of the platters can sometimes result in vibration |
| Heat Produced | Lower power draw and no moving parts so little heat is produced | HDD doesn’t produce much heat, but it will have a measurable amount more heat than an SSD due to moving parts and higher power draw |
| Failure Rate | Mean time between failure rate of 2.0 million hours | Mean time between failure rate of 1.5 million hours |
| File Copy / Write Speed | Generally above 200 MB/s and up to 550 MB/s for cutting-edge drives | The range can be anywhere from 50 – 120MB/s |
| Encryption | Full Disk Encryption (FDE) Supported on some models | Full Disk Encryption (FDE) Supported on some models |
| File Opening Speed | Up to 30% faster than HDD | Slower than SSD |
| Magnetism Affected | An SSD is safe from any effects of magnetism | Magnets can erase data |
| Data Recovery | Difficult | Relatively easy |
| TBD | TBD | TBD |
END.
