[INTRODUCTION] | [LV-ROM] | [LASERDISCS] | [SCSI] | [VFS] |[TV COVERAGE]

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The 1986 Domesday project was a project on an unprecedented scale, consisting of a vast collection of text, photographs, data and even video clips. As a result a significant amount of data needed to be stored, a mass storage medium was required as the floppy discs simply could not hold this amount of data.

The LaserVision VideoDisc system from Philips was seen as a way of storing the many photos as individual video frames that could be selected using a microcomputer. At the time there were already a number implementations of VideoDisc Players that could be controlled by a computer but the VideoDisc did not contain any computer data, the computer simply acted as a remote control device for the player. Philips were approached as they produced the only videodisc players made in Europe. Initially the BBC considered using full frame Teletext to store the data on the disk as Teletext had been previously included on a VideoDisc titled "British Garden Birds" where teletext subtitles were used to provide further information. While this approach worked for the small amount of text required for subtitles it was not to prove suitable for the volume of data required for Domesday. The main limitations being that using full frame teletext it would not be possible to store the photo and data in the same frame. As a result it would mean that where data was required a picture could not be stored. The other problem was that Teletext has very limited error correction capabilities that would not be able to compensate for scratches on the disc or framing errors from wow and flutter of the disc.

The BBC consulted with Philips who eventually suggested that it would be possible to replace the standard analogue stereo audio tracks with a PCM digital data channel essentially using the same technology that was just emerging for CD-ROM. The data channel would provide over 300 Megabytes of data on each side of a disc. Essentially creating a hybrid of CD-ROM with but with the addition of video frames. A special player was designed called an LV-ROM player that could extract the data from the new data channel and present it over a SCSI interface. Phillips announced that they would be developing a new LaserVision player in November 1984 for the domesday project. The VP-415 Laserdisc player was the only player produced with the special SCSI interface and was therefore the only player that could be used for the Domesday project.

The fact that the player was a one-off and only produced in small quantities has resulted in the players being quite rare. Spares to repair players are virtually non existent as no other player shared the components in the VP-415.

The LV-ROM concept was probably the best choice at the time but it's life span was limited and has caused a few problems with conserving the information for the future. Not long after the Domesday project was completed CD-ROM became established as the de facto mass optical storage medium for computers and so very little further development went in to LV-ROM. With the advent of DVD even the standard Laserdisc for video has all but disappeared now. As the pictures are analogue and the data held in a proprietary format it has not been possible simply to copy the information from one media format to another.

There have been a couple of projects have attempted to conserve the data, one attempting to emulate the original system on a modern PC the other converting the data and implementing new software to read it on a modern PC.

History of LaserDisc
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The idea of an optical media for storing video is not as new as may at first be thought. Amazingly a optical disc using a transparent disc is thought to have first been invented by David Paul Gregg in 1958. It was however not until the Dutch electronics company Philips started development of an optical videodisc format that the idea became a reality, by 1969 they had developed their first videodisc that was publicly demonstrated in 1972. The first video disc format was in fact marketed in the USA as Discovision in 1978 a forerunner to LaserDisc. LaserDisc was originally an analogue video disc system based upon the same laser optical disc technology used by the Compact Disc.

LaserDisc was reasonably successful due to its high quality reproduction but not an outright success. LaserDisc can deliver quality with a clarity and precision unmatched by any of the domestic video tape systems available at the time including the later High Band formats such as SuperVHS and Hi-8. Only 'professional' video tape formats such as 1" C format or D-2 video tape recording systems could match the quality of LaserDisc. It was the ability of LaserDisc to deliver high quality pictures that made it the format of choice for video enthusiasts the world over before the advent of DVD. LaserDisc also shares the convenience features of Compact Disc, such as rapid random access. Despite all these apparent advantages LaserDisc was not a mass market success due largely to the fact that The systems cost more than a video recorder and could not record broadcast programmes.

LaserDisc in the UK
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Since LaserDisc stores a complete analogue video signal, it does suffer from division into two separate formats; the American 525 line 30 frame per second NTSC (EIA) video system and the European 625 line 25 frame per second PAL (CCIR) video system. As a result the development of LaserDisc in the UK lagged behind America. Unfortunately, due to the smaller size of the UK market the market for PAL LaserDisc was never very well developed further hastening the demise of the format in the UK. Philips partnered with Japanese manufacturer Pioneer in 1984 who purchased the majority stake in the format and effectively took over marketing of LaserDisc video. This unfortunately seemed to result in Philips beginning to ease off promotion of LaserDisc choosing instead to allow Pioneer to take over the format. Pioneer have provided may innovations of their own over the years and have remained committed to the video format. Unfortunately for the Domesday project the switch in direction with Philips shifting its attentions to CD-ROM and ultimately Compact Disc Interactive and Pioneer concentrating on video there didn't seem to be much interest in continuing development of LV-ROM format resulting in the demise of the format.

Some criticism has been has been aimed at the BBC project team for selecting the LV-ROM format. Such criticism is unfounded as there was simply no effective way at the time to store both images and data. The Domesday project was conceived using technology available in 1983-1986. There was no such thing as digital photographs on computers of the time the memory and graphics capabilities were simply not capable of reproducing photos. Mass storage systems such as CD-ROM were not readily available and the optical format of the time was Laserdisc. Had CD-ROM been available it would still require a huge number of CD's to store all the images as no MPEG or JPEG compression was available at that time. The project management chose Laserdisc as the storage format due to the ability to hold many thousands of images as single video frames on a single disc.

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