Application of Hard Disk Storage Technology in Video Surveillance

1. Current situation and existing problems

With the increasingly severe international anti-terrorism environment, as well as new technologies driving new applications of monitoring, especially the increasing requirements of enterprises for security protection, monitoring has gradually entered people's daily lives. The security monitoring market is moving towards networking and intelligence. This requires security products to improve their quality and reliability, segment products based on application characteristics, reduce total costs, and be green and environmentally friendly, and create a sales and service system that adapts to the security industry.

Hard disk is one of the most important devices in the monitoring system, which plays a role in protecting data security. Traditional hard disk is not suitable for the field of security monitoring, because long working hours and harsh working environment are a huge test for ordinary hard disk. Professional hard disks that are more durable, reliable, stable, low-power and low-noise will be more suitable for the special requirements of the field of security monitoring.

2. Introduction to Hard Disk Storage Technology

1.Intelliseek-Intelliseek technology

At present, hard disks have unique intelligent seek technology that can actively calculate the optimal seek speed to reduce the hasty operation of the actuator, thereby reducing noise and energy consumption. With intelligent seek technology, the operation of the actuator is effectively controlled, and the head can accurately contact the next sector to read new information instead of hastily rising and waiting for the hard disk to rotate. The smooth operation makes the seek operation quieter and the vibration is greatly reduced. The security monitoring field is a field with high requirements for product power consumption and hard disk life. If the disk's mechanical arm moves too fast, it will cause the hard disk to consume too much power, affect the life of the mechanical arm, and increase the probability of failure.

2.RotaryAccelerationFeedForward (RAFF)

This technology is widely used in SCSI products. It detects hard disk vibration and compensates for performance by adding vibration sensors to the hard disk control PCB. This feature is particularly useful in complex environments with multiple hard disks. The hard disk will generate two types of vibrations when it is working, one is horizontal and the other is vertical. The vertical vibration is easy to understand. The harm of this vibration is that it is easy to cause the head to collide with the disk. The horizontal vibration is because the disk will rotate at high speed when the hard disk is working. While rotating, it will generate centripetal force to drive the hard disk to move in the horizontal direction. The simultaneous horizontal movement of multiple hard disks may interfere with other hard disks, that is, the phenomenon of the head deviating from the track will occur. Although the transmission system will automatically return the head to the correct position, this will cause unnecessary delays.

Rotational vibration compensation is a technology designed for rotational vibration. The hard disk is equipped with a rotational vibration sensor. Once the surrounding hard disks rotate at the same time and produce rotational vibration, the sensor will generate a displacement signal, allowing the head to return to its original position more quickly, reducing the impact of head deviation caused by rotational vibration.

3. Ramp Load Technology

Usually, when the hard disk is in working state, it will not only generate horizontal vibration, but also vertical vibration. Vertical vibration is extremely harmful to the hard disk. Once the hard disk vibrates vertically, it is easy to cause hard disk failure. Traditional hard disks set up a textured hovering area in the disk memory part that only relies on the motor. When the hard disk is powered on, the slider carrying the head slides on the surface of the disk until the disk rotates fast enough to create an air cushion between the two to lift the slider. At this time, the head gradually moves to the sector where data is stored and starts to work normally. Hard disk power failure can be regarded as the reverse operation of power on. After power failure, the head will rely on the inertia of the motor to move back to this special hovering area until the inertia disappears and the hard disk stops working completely. The hard disk using RampLoad ramp loading technology can easily solve this problem. It has improved the traditional design and moved the head rest area inside the motor to the outside of the disk to establish a separate area. This can prevent the head (sled) from falling from the hovering area and contacting the disk under the impact of external force, reducing the probability of contact between the head (sled) and the disk (when the hard disk is turned off, the head is outside the disk and there will definitely be no contact; after the hard disk is running, if it is in the idle state, the head can also return to the bracket instead of flying over the disk all the time). RampLoad ramp loading technology can also reduce the power consumption of the hard disk. When the head returns to the standby area, the power consumption is bound to be lower than when the head is hovering on the surface of the disk. For security monitoring hard disks that are in standby state for a long time, this technology is very necessary. In this way, the buffering principle of the ramp is used to separate the rotating head and disk before and after the hard disk is started, reducing the friction and loss between the head and the disk surface, making it more energy-efficient and optimizing the electronic components, thereby ensuring the reliability of the long-term operation of the hard disk.

4. Fluid dynamic bearing motor

The difference between the liquid bearing motor and the traditional steel ball bearing spindle motor is that it uses oil film instead of traditional steel balls, which means that there is no metal contact when it rotates, so theoretically there will be no wear problem. This allows the bearing to effectively absorb external vibrations and protect the bearing surface. It can withstand greater impact force, extend its life and reduce noise. This is a hard disk shockproof technology that can greatly reduce the working noise and heat of the hard disk, and even if it is installed in some thin and light notebooks with poor sound insulation, the working noise is unpleasant.

3. Advantages and characteristics of hard disk storage technology

In recent years, with the development of security monitoring products and the special requirements of the market, hard disks have shown unprecedented highlights in all aspects. For example, hard disks are particularly good at reducing vibration and noise. They use unique (IntelliSeek) intelligent seek technology to optimize seek speed. While reducing energy consumption, noise and vibration, they more effectively control the operation of the actuator, which plays a vital role in the head accurately contacting the next sector to read new information. In terms of smooth operation, the energy consumption of hard disks is reduced by about 60% compared with the past, and its seek operation is quieter and vibration is greatly reduced. Secondly, SilkStream technology is optimized for smooth and continuous digital video recording and playback, which can support up to 12 HD video streams, and the liquid bearing motor reduces noise and improves reliability. The advanced power management function ensures that electronic components provide first-class low power consumption to meet the requirements of reducing power consumption and increasing reliability. Ramp Load technology ensures that the head is parked when the hard disk is started, stopped and not working. In addition, the multi-layer cast stainless steel shell and the precisely designed base minimize the working noise. At present, the noise produced by hard disks has been tested to be less than 1 Sone (15 decibels), which is almost inaudible to human ears. At present, the characteristics of hard disk products can be summarized as follows: reliability, low power consumption, low heat dissipation, and high shock resistance.

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1. Long-term reliability

(1) Industry-leading 1 million hours MTBF;

(2) Designed for surveillance video systems that work at high temperatures 24/7 (0-70 degree panel temperature);

(3) SilkStream technology supports streaming commands and ATA7, and uses CCT optimized for audio and video recording and playback. It provides optimization for long-term reading and writing of audio and video data, and improves the stability and reliability of audio and video reading and writing.

2. Low power consumption and low heat dissipation

(1) IntelliSeek function optimizes seek speed and reduces noise/power consumption/vibration;

(2) Ultra-low starting current of 1.5 amps reduces the impact of powering on the hard drive.

3. High vibration resistance

RampLoad slope loading technology ensures that the head never contacts the disk, which greatly improves the hard disk's non-operating vibration resistance and improves long-term operation reliability.

4. Streaming media optimization

Streaming media has three major features: continuity, real-time, and timing. It is the most suitable carrier for storing security monitoring recorded videos. SilkStream is a special technology developed by AV series hard disks specifically for streaming media. It is optimized for smooth continuous digital video playback and can support up to 12 concurrent high-definition digital video streams. SilkStream is compatible with the ATA stream control instruction set and can provide users with standard stream management and error recovery functions. This technology can solve the service quality problems related to fragmentation, so the performance will not decrease over time, and improve the reliability of the hard disk, reduce on-site DVR system failures, and reduce the hard disk task load.

4. Application Status of Hard Disk Storage Technology

At present, hard disk capacity is suitable for audio and video applications such as digital video recorders and surveillance imaging systems, including digital video recorders, IP gateways and mainstream surveillance systems, which often require hard disks to operate continuously 24 x 7 and have more stringent requirements than personal computers, such as higher reliability and compatibility, lower energy consumption, and the ability to record multiple audio or high-definition video streams simultaneously. In consumer applications, digital video recorders must cope with harsh environments and usage profiles, which means that the hard disks they are equipped with consume less energy, generate less heat and operate quietly, which is more suitable for market application needs.

After testing, the startup current of a standard hard disk is only 2.8A, and the 12V startup energy consumption is only about 35W, which will not cause too much burden on the power supply. However, for a multi-hard disk environment such as DVR, the startup current of 2.8A is relatively high. If a monitoring system using 8 hard disks is assembled, the 12V energy consumption is close to 270W. If a hard disk with a lower startup current is used, the power supply will be reduced. The startup current of the current new hard disk is only 1.8A, so the 12V energy consumption is at most about 200W, which reduces the power supply requirement by nearly 100W, which can reduce the overall cost of the DVR; and it has the characteristics of quiet operation, low temperature, high reliability and fast data transmission speed, as well as SilkStream, IntelliSeek, IntelliPark and IntelliPower and other technologies, which are very suitable for various audio and video applications, such as PVR, DVR, set-top box (STB) and video surveillance recording. At the same time, green environmental protection has also become an important direction for the development of hard disk technology. Currently, a variety of green energy-saving technologies are applied, such as: IntelliPower - designed for both significant energy saving and stable operating performance, it can achieve a good balance between operating speed, transfer rate conversion rate and cache capacity. In addition, GreenPower hard disks consume less power when starting, thereby reducing the peak load pressure of the system; IntelliSeek™ - calculates the best seek speed to reduce energy loss, noise and vibration during operation, fully utilizes the waiting time of motor rotation to reduce seek speed, and reduces noise/power consumption/vibration; IntelliPark - reduces aerodynamic resistance by automatically unloading the head when idle, suspends the operation of read/write channel electronic devices, and thus reduces energy loss. In addition to the application of IntelliPower, IntelliSeek and IntelliPark technologies to ensure silence, it also uses a multi-stage formed stainless steel top cover and precision-designed basic accessories to minimize the sound of the hard disk during operation, catering to the characteristics of consumer applications that are sensitive to sound. This is of great significance to the application and development of hard disk storage technology in the field of audio and video surveillance and the promotion of green and energy-saving storage.