Long before the CDs and the likes, we had portable data storage media such as floppy disks. This was around the early 70s and used to be 8 inches in size. “Floppy” because they were flexible. Soon it gave way to 5¼ inch floppy disks, storing up to 1.2Mb. Around the 80s we saw the introduction of the smallest of the floppy disk family in the 3½ inch size – this was not flexible. Data in floppy disks would have to be constantly backed up as integrity used to be a big question with them. Alternatively data centers used to back up data in magtapes.
This is when Compact Disks as storage device made inroads, more popular as CDs. This is the story of 80s. Having started with pre-recorded CDs, it soon offered facility of one-time recording at user end; later we also received the re-writable ones. The catch would lie in the drives; the ancient drives did not accompany the recording software; they were capable of playing the CDs alone. While CDs can hold data as well as audio tracks, floppy disks did not offer the capability. CDs allowed up to 700Mb of data storage – a quantum leap from floppies. Although CDs certainly offered more resistance to extreme temperatures and water, it still could be rendered useless with dust and scratches. CDs also sounded the death knell for cassette tapes, 78 RPM gramophone records and 33 1/3RPM vinyl; although the latter two were overtaken some time ago by the former as they were not portable, could break easily and you could not record your own favorites on it. The advent of CDs brought in its wake the CD walkmans, thus making cassette walkmans a story of the past.
In the 90s we saw VCDs and later DVDs – these were more versatile than CDs as they offered up to half a dozen times more storage. Apart from that, they would facilitate high quality, standard definition video distribution and recording. They look the same as CD/VCDs but are more rugged and would employ the same factor as that of CDs and thereby provide flexibility for full backwards compatibility. It can hold full length movies as well – something that CDs did not permit. Even VCDs, at times would split a movie in multiple disks.
By this time, High Definition television sets had begun to flex its muscles in the markets. Soon people realized that there was no choice for media capable of recording or playing back High Definition substance.
High Definition (HD) DVDs then evolved from DVDs with marked advanced features. It began appearing in the markets around mid 90s. Comparable to older VHS videotapes, this came to supplement the recent introduction of TVs capable of reproducing high definition pictures. Apart from offering superior “unforgettable experience” picture high definition DVDs allow you to pack more movies in a single disk. HD-DVDs provide 1080 lines of video resolution and thus is far more advantageous than DVDs that can offer no more than 576/480 lines.
Around the same time, Shuji Nakamura, well aware that one could create high density optical storage using lasers with shorter wavelengths, introduces us to practical blue laser diodes and thus the blu-ray disk was born.
It may be worthwhile to note that while HD-DVD is supported and serviced by NEC, Toshiba, Universal studios, Paramount Pictures, Warner Bros and the like, Blu-ray found backing of Philips, Hewlett-Packard, Sony, Dell, Hitachi, Hewlett-Packard, Samsung, Panasonic, Pioneer and the likes.
Both the disks are same by appearance and size when compared to VCD, DVD or CDs, but are different by storage capacity and technology. The blu-ray disk, with its shorter wavelength blue laser, smaller aperture lens and thinner cover layer on the surface of the disk and smaller beam spot size – is capable of allowing storage up to 50Gb, depending on whether it is a single layer or dual. HD-DVD, on the other hand is capable of storing 15 GB on a single layer disk and 30 Gb on the dual layer disk.
With a minimum capacity of 25 GB over 4.5 offered by a standard DVD, blu-ray has easily grabbed the limelight. Compared to DVD’s 8MBps, blu-ray is mightier with the ability to produce signals at the speed of 48MBps making it 6 time faster. Not only does blu-ray disk offer comparably higher bandwidth, the properties of blu-ray also allow capturing a full 1080p High Definition image giving a resolution of 1920 x 1080 progressively scanned pixels. You might remember the DVDs would provide no more that 720 x 480.
So you can see that HD-DVD and Blu-ray – both are serving the same purpose but are two different formats available to customers to choose from.
The evolution inarguably would continue, media and players will continue to come and go; people will continue to lose money with the outdated players, if not the media – because technology does not and cannot stand still.