Digital video surveillance is widely used to enhance the physical security and safety of government institutions, corporations, public spaces and even schools and private homes, says Richard Makwela, Western Digital product specialist at Drive Control Corporation (DCC).
Frequently users hear news reports about how criminals were apprehended after they were caught “on tape”. However, more often than not we hear that the footage was deleted off the security surveillance system only a few days after an incident occurred due to hard disk drive (HDD) space constraints or disk failures.
While digital surveillance was first introduced as a cumbersome technology in the 1940s, the technology has made a rapid transition from high-cost analogue to more affordable digital security systems.
With increased presence and enhanced requirements of modernised closed-circuit television (CCTV) systems, there is a need for specialised HDDs with more storage capacity and advanced features designed specifically for surveillance mediums.
In fact, today’s AV hard disk drives are very different from ordinary desktop or enterprise hard drives. If users consider that an average desktop hard drive is designed to run for nothing more than an eight hour day, today’s surveillance systems run 24 hours a day, seven days a week. They are optimised for multiple continuous sequential write operations onto the drives from different audio and visual sources.
Today’s systems deliver a comprehensive range of features and capabilities such as high-resolution image quality, streaming video from multiple cameras, video archiving with ultra-fast data access and on-demand video playback.
AV drives provide full support for ATA streaming commands to measure performance and to minimise error recovery time limits in favour of completing operations on time. This means that while the video quality is not always ideal, all the desired frames are captured.
To understand which HDD is right for any particular application, one must first look at the recording system being used and how it is being used in conjunction with newer technologies, such as biometrics and smart sensors.
Surveillance drives are available in three distinct classes: AV-class, enterprise class and solid state. Irrespective of the industry, the vast majority of surveillance systems used worldwide fall into one of six types. These include:
* A Standalone digital video recorder (DVR) records video streams from one or more cameras. The video is recorded onto up to six hard drives, which are housed in the device itself. Typically small to mid-sized commercial facilities and home users favour these devices and AV-class drives have proven to be the best choice with low power consumption, 24/7 reliability and ease of use.
* Hybrid and PC-based SDVR systems integrate analogue and digital video sources and provide local playback and search features on a PC. Organisations such as banks, small casinos and shopping malls and schools make use of this type of surveillance as it supports remote management and reporting features. AV-class storage and solid state storage are commonly used for these systems.
* Network video recorders (NVRs) and video management systems (VMS) are systems that provide active analysis of recorded video, such as people counting, license plate recognition and monitoring of virtual boundaries.
These advanced systems are used by governments, as well as casinos and commercial buildings, airports and manufacturing plants. AV-class storage as well as enterprise-class storage are best suited for these applications and are RAID-ready.
* Mobile SDVR systems are used in vehicles and transportation systems such as police cars, armoured trucks, trains, buses and airlines, as well as military vehicles and vessels. This environment is typically hostile, such as high-motion or extreme temperature environments and solid state storage has been proven to be the best solution for these conditions to avoid disk failure.
* Finally, surveillance storage expansion drives are external drives with AV-class storage inside and are engineered for 24/7 use. Because the solution is external, storage can be scaled as the need arises, or archived for analysis. These external drives are typically USB-enabled.
In closing, regardless of surveillance environment, whether its banking, casino, retail, commercial, corporate, government or law enforcement, surveillance based hard drives are the foundations that deliver the superior performance, added capacity, and enhanced reliability that surveillance applications require.