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Ultra Density Optical (UDO) is an optical disc format designed for high-density storage of high-definition video and data. The format was introduced by Sony to replace the Magneto-optical disc format.
An Ultra Density Optical disc, or UDO, is a 133.35 mm (5.25") ISO cartridge optical disc which can store up to 30 GB(gigabytes) of data. The second generation UDO2 media format was introduced in April 2007 and has a capacity of up to 80 GB. It utilises a design based on the Magneto-optical disc, but uses Phase Change technology combined with a blue violet laser, a UDO/UDO2 disc that can store substantially more data than a magneto-optical (MO) disc. This is due to the shorter wavelength (405 nm) of the blue-violet laser employed. MOs use a 650 nm-wavelength red laser. Because its beam width is shorter when burning to a disc than a red-laser for MO, a blue-violet laser allows more information to be stored digitally in the same amount of space.
Current generations of UDO2 media store up to 60 GB.[1] According to Plasmon, desktop UDO2 drives are priced at around US $5400.[2] A 30 GB UDO2 Write Once is US $75.[2]
UDO optical disc storage media was developed as a replacement for the 9.1 GB Magneto-optical digital storage medium. The Ultra Density Optical was first announced by Sony on November 1, 2000.[3] It was later adopted with heavy investment by Plasmon, a UK technology company with extensive experience with computer archival backup systems and solutions.[4]
Currently, UDO/UDO2 is being championed by its development partners Plasmon, Asahi Pentax (responsible for the opto-mechanical assembly design), Mitsubishi Chemical, parent company of the Verbatim media storage brand, and various computer and IT solutions companies. Mitsubishi Chemical is the second major development partner of UDO media and the sole manufacturer of UDO media as of the 4th quarter of 2008.
On November 10, 2008, Plasmon creditors (led by Silicon Valley Bank) closed down Plasmon LMS (company) as CEO Stephen "FX" Murphy was not able to secure funding to keep the money-losing company afloat. The UDO media factory in the UK was shut down and dismantled.
On January 13, 2009, Alliance Storage Technologies, a Colorado Springs Manufacturer of optical technology and Service Provider, acquired the assets of Plasmon (including UDO and UDO2 technology) in a liquidation sale. ASTI currently sells and supports UDO technologies sold under the Plasmon brand.[5]
ECMA-380: Data Interchange on 130 mm Rewritable and Write Once Read Many Ultra Density Optical (UDO) Disk Cartridges –Capacity: 60 Gigabytes per Cartridge – Second Generation[6]
UDO uses a Phase Change recording process that permanently alters the molecular structure of the disc surface.
There are three versions of UDO/UDO media: a True WORM (Write Once Read Many), an R/W (Rewritable), and Compliant WORM (shreddable WORM).
The table below summarizes the differences between conventional Magneto-Optical specifications and those of the enhanced Ultra Density Optical disc.[7]
| Disc | 5.25-inch UDO Rewriteable | 5.25-inch UDO Write Once | 5.25-inch MO system (9.1 GB) |
|---|---|---|---|
| Disc diameter | 130 mm | 130 mm | 130 mm |
| Disc thickness | 2.4 mm | 2.4 mm | 2.4 mm |
| Cartridge size | Same as ISO 130 mm (135 x 153 x 11 mm) | Same as ISO 130 mm (135 x 153 x 11 mm) | ISO 130 mm (135 x 153 x 11 mm) |
| Number of physical tracks | 96,964 | 96,964 | 49,728 |
| Sector size | 8 kB | 8 kB | 4 kB |
| Number of sectors | 2,504,407 | 2,504,407 | 1,118,880 |
| Data area | 29.0-61.0 mm | 29.0-61.0 mm | 29.7-62.5 mm |
| Designated[a] laser wavelength | Violet (405 nm) | Violet (405 nm) | 660 nm |
| Objective lens (NA) | 0.85 | 0.85 | 0.575 |
| Recording layer | Phase change | Phase change | Magneto-optical |
| Recording format | Land & groove | Land & groove | Land & groove |
| Recording side | Both sides | Both sides | Both sides |
| Track pitch | 0.33 µm | 0.33 µm | 0.65 µm |
| Minimum bit length | 0.13 µm | 0.13 µm | 0.3 µm |
| Recording density | 15.0 Gb/in² | 15.0 Gb/in² | 3.3 Gb/in² |
| Transfer rate | 4-8 MB/s | 4-8 MB/s | 3-6 MB/s |
| Error correction | LDC | LDC | LDC |
| Modulation | RLL (1,7) | RLL (1,7) | RLL (1,7) |
UDO Drives Specifications Summary
UDO comes in both internal and external drive guises. External drives are also available as part a robotic autoloader. All current drives are designed for heavy duty use.
UDO systems use a blue-violet laser operating at a wavelength of 405 nm, similar to the one used in Blu-ray Disc, to read and write data. Conventional MOs use red lasers at 660 nm.[8]
The blue-violet laser's shorter wavelength makes it possible to store more information on a 13 cm sized UDO disc. The minimum "spot size" on which a laser can be focused is limited by diffraction, and depends on the wavelength of the light and the numerical aperture of the lens used to focus it. By decreasing the wavelength, using a higher numerical aperture (0.85, compared with 0.575 for MO), the laser beam can be focused much more tightly. This produces a smaller spot on the disc than in existing MOs, and allows more information to be physically stored in the same area. [1]
The opto-mechanism design of current Plasmon UDO drives was jointly developed with Asahi Pentax.
Currently UDO has an expected data archival life of around 50 years. Apart from the storage size, the discs (like Magneto Optical discs) are designed for durability and long term reliability.
A company called Blu-Laser Cinema announced in June 2005 that it was launching a new player using the UDO format to provide a secure viewing and editing platform for film production houses. Targeted towards the high-end video editing and production community, the unit featured a smart card reader and a USB dongle with an embedded biometric fingerprint reader to allow access only to authorized users.[9]
The core technology for UDO is essentially similar to Blu-ray Discs, as well as PDD (all were developed by Sony), although there are a number of key differences; the primary ones being:
