The word convergence has taken on more importance as CCTV systems make way for digital open connectivity. Much of our old analog technology is being replaced by computers with seemingly endless amounts of storage. But is it really endless?
When I was much younger, I remember tinkering around with my Packard Bell 486 33/66 MHz computer. Truly high-end technology, this computer boasted 2MB RAM and a 150MB hard drive that ran DOS/Windows 3.1. I even had the option of a selectable processor speed so when I wanted to work more slowly, I could switch it to 33 MHz. As you can imagine, I didn't often use that feature.
Being somewhat of a computer aficionado in those days, I soon required more space and a much larger hard drive. I remember reading in a sales newspaper about a 1GB hard drive and drooling at the thought that I would never run out of space. I hurriedly bought the technology for $300.
Fast forward to today. I am again drooling about a new storage solution, this time a 1GB Secure Digital (SD) media storage device for my Palm Pilot that costs $35 with a $60 mail-in rebate.
Storage will never be endless, and this has caused particular problems for digital video recording in security applications.
Never Enough Room
Digital video recording requires a mind-numbing amount of storage. DVR manufacturers have developed innovative ways to cut down on storage by manipulating frame capture, resolution, capture size and refresh methods, but these are not ideal when compared to the old analog linear recording method. If linear recording is what you need, you're in for a storage surprise.
Let's hypothesize that your organization needs a digital video recorder that will record 100 cameras at high resolution, at a minimum of 3.75 frames per second (comparable to the multiplexer/VCR combination) linear, with a screen capture of 640 x 480.
Now, for argument's sake, let's hypothesize that one frame of recording would require 15k of storage. (This is a low estimate, but it will help illustrate the problem.) That means every recorded second would require 56.35k of storage (3.75 x 15). Every minute would require 3.3MB. Every hour would require 198MB. Every day would require 4.7GB. Every month would require 139GB.
139GB is a lot of space, and we're not even through yet. Once we have this number, we need to multiply it by the number of cameras (100), which gives us a grand total storage requirement of 13.6TB. Yes, that's terabytes. The largest magnetic hard disc you can buy will support 500GB. And keep in mind that we used an unrealistic 15k rate of capture for a single frame of video. If we increase that to a more realistic 35 to 50k, then you can imagine how fast the number grows.
Holographic Data Storage
In 2002, I wrote an article for ST&D's January CCTV supplement entitled “The Digital Bandwagon.” In that article I wrote about holographic data storage (HDS), which was being developed by InPhase Technologies. The company has been quietly making advances in HDS technology, which I predict will be an industry leader in storage by 2010.
HDS technology approaches storage from a three-dimensional perspective—layers upon layers of information can be read and written to a small proprietary cartridge. This is one of the few optical technologies that can write as fast as, or faster than, the optical or magnetic tape drives that we have now.
Unlike many of our current storage media, HDS is immune to electromagnetic and radio frequency interference (which is why the government is interested), and it is predicted to securely store data for as long as or longer than current optical technologies. In addition, the read and write head does not physically touch the media, which makes it less susceptible to physical hard drive crashes.