• SSD

  • HHD

Overview:

1. Solid State Drive (SSD), the internal structure of the SSD is not as complex as the HHD, SSD is a hard disk with solid state electronic storage chips arrayed from the control unit and storage unit, the storage medium is divided into two types, one using flash memory (FLASH chips) as the storage medium, the other is the use of DRAM (DRAM chips) as the storage medium.

Inside the SSD, the most core part is the controller, which is the heart of the entire SSD, including many architectures, such as read and write algorithms, interface definitions and so on. SSDs are identical to traditional hard drives in terms of interface specifications and definitions, functionality and usage, and are also identical to traditional hard drives in terms of product shape and size, with greatly improved I/O performance compared to traditional hard drives.

The chips have a wide operating temperature range of commercial (0 ~ 70°C) and industrial (-40 ~ 85°C). Although the cost is higher, it is also gaining popularity in the DIY market.

Because SSD technology is different from traditional hard drive technology, it has given rise to a number of emerging storage manufacturers. Manufacturers can build SSDs by simply purchasing NAND memory and pairing it with the appropriate controller chip.

2. Mechanical Hard Disk (HHD): that is, the traditional ordinary hard disk, mainly composed of: disk, head, disk spindle and control motor, head controller, data converter, interface, cache and other parts.

In the center of each HHD, there are a large number of high-speed rotating disks, all the disks in the HHDs are mounted on a rotating axis, each disk is parallel to each other, the disk is covered with a layer of small and thin magnetized metal particles, data in a form that can not be distinguished by the naked eye, many groups of tiny particles formed by the magnetization pattern records form the data, each group of data is also called bit, all The particles are arranged according to their own magnetism, which works similarly to the CD-ROMs we normally use. The advantage of a SSD is that it can store more things than a SSD at the same price.

The surface of each disk has high-speed sweeping recording heads, the distance between the heads and the disk is smaller than the diameter of a hair, all the heads are linked to a head controller, and the head controller is responsible for the movement of each head, the heads can move along the radius direction of the disk, together with the high-speed rotation of the disk of several thousand revolutions per minute, the heads can be positioned at the specified location on the disk for data reading and writing operations.

Information is passed through the magnetic surface very close to the magnetic head, by the electromagnetic flow to change the polarity way by the electromagnetic flow to write to the disk, the information can be read in the opposite way. As a precision device, dust is the big enemy of the hard disk, so the air entering the hard disk must be filtered.

SSD advantages:

1. Read and write speed: the use of flash memory as a storage medium, read speed is faster compared to mechanical hard drives. SSD do not use magnetic heads, and the seek time is almost 0. The sustained write speed is amazing, and most SSD manufacturers say they will claim that their own SSD sustained read and write speeds of more than 550MB/s! SSDs are definitely not only fast in terms of sustained read and write, but also in terms of random read and write speed, which is the ultimate mystery of SSDs and is most directly reflected in the vast majority of daily operations. Related to this is the extremely low access time, the most common 7200 rpm mechanical hard drive seek time is generally 12-14 milliseconds, while SSD can easily reach 0.1 milliseconds or even lower.

2. Shock and drop resistance: traditional hard drives are disk-based, with data stored in the disk sectors. While SSDs are made using flash memory particles (i.e., mp3, U disk and other storage media), so SSD hard drives do not have any mechanical parts inside, in the event of collisions and shocks to minimize the possibility of data loss.

3. low power consumption: the power consumption of SSD is lower than that of traditional hard drives.

4. no noise: SSD do not have mechanical motors and fans, working at a noise level of 0 decibels. There are no mechanical moving parts inside, no mechanical failure, and no fear of collision, shock, vibration. Because SSDs use flash memory chips with no mechanical parts, they have the characteristics of low heat generation and fast heat dissipation.

5. Large operating temperature range: Typical hard disk drives can only operate in the range of 5 ~ 55 degrees Celsius. Most SSDs can operate at -10 ~ 70 degrees Celsius. The interface specification and definition, function and usage of SSD are the same as those of ordinary hard drives, and they are also consistent with ordinary hard drives in terms of product shape and size. The chips have a wide operating temperature range (-40 ~ 85 degrees Celsius).

6. Lightweight: SSD are very light in weight, compared with the conventional 1.8-inch hard drive, 20 ~ 30 grams lighter, now M.2 and other SSD can do and memory size, compact and lightweight, very convenient to carry every day.

SSD compared to HHD:

1. Access speed

SSD have a great advantage in transfer speed, up to 500M / s, where the read speed reaches 400-600M per second, the write speed can also be as high as 200M per second. For 1G files in just a few seconds, while the traditional IDE hard drive read speed limit is unable to exceed 200M per second, write speed is also difficult to break 100M per second, usually basic in a few dozen M per second.

2. Economic price

Solid-state more disk in speed and security has a great advantage, because it is the latest technology so in terms of price relative to traditional hard disk is much higher, SSD are now generally 2-3 times the price of traditional hard disk.

3. Data security

We all know that the traditional hard disk is through the head to read the disk to complete the data read and write, especially in the high-speed rotation process of the disk and head collision is more likely to cause data damage, and solid-state hard disk no disk, so as long as its chip is not extruded by the shape of the deformation, the data can be safely preserved, so the difference between solid-state hard disk and ordinary hard disk in terms of data security is great.

Generally speaking, HHD damage data can be recovered, but this is not 100%, individual cases can also cause unrecoverable. The SSD data is basically very difficult to recover, and this is the biggest shortcoming of the SSD. So it is recommended that if you have important information or exist in the mechanical hard drive is safer, or use a different SSD for backup. At least for now, it is unknown later.

4. Seismic capacity

HHD because of the use of high-speed rotating platters and heads back and forth seeking the principle of reading and writing data, so there can not be high-intensity vibration, otherwise the heads and high-speed rotating platters in contact with the platters will cause scratches and damage to the platters, resulting in the scrapping of the hard disk, so the use of HHD must avoid the occurrence of vibration, while SSD use solid-state electronic memory chip arrays, welded to the circuit board, compared to HHD has lighter and thinner body and better shock tolerance.

5. Power consumption and noise

HHD high-speed rotation of the disk requires a high-powered stepper motor to drive, while SSD do not require a motor to drive, so HHD in power consumption is much larger, working due to the rotation of the motor, there will be a small vibration and noise, while SSD are not these problems.

How to choose:

Need for speed: If you have specific requirements for storage speed, then you go for SSD.

Gamers: Anyone who plays games knows that SSDs are a must, so SSDs are still a favorite for people who play games.

Work travel: If you need to travel regularly for work, SSDs are certainly the first choice because they are small and have good shock resistance to ensure the safety of corporate data.

General users: If you do not have extreme requirements for speed and do not need to carry it around, you can consider mechanical hard drives

Summary:

1. From the appearance of the comparison of SSDs are much smaller than mechanical hard drives, conducive to notebooks to reduce the thickness.

2. SSD do not have the motors used in mechanical hard drives and start up very fast. Because SSD do not need heads, the speed of reading is several times that of mechanical hard drives, even if the disk fragmentation will not affect the reading speed.

3. SSDs do not have mechanical motors and electric fans, so there is no noise, HHD can be understood as a precision instrument, SSDs are an integrated circuit, so the shock resistance and temperature adaptability is higher than HHD.

4. The high cost of SSD, and the capacity has been much lower than mechanical hard drives. Limited by the number of reads and writes, the service life of SSD is relatively short.

5. Disk fragmentation does not affect the SSD read, but affects the disk write, the speed is lower than the HHD. More susceptible to external interference than mechanical hard drives, and data damage is difficult to repair.

In terms of VPS hosting server, there are both SSD and HHD. Many providers just provide the VPS hosting server with HHD whose I/O speed is slow, LightNode's VPSes all use SSD, you can get a high speed to transferring data.