Call/Recall is a new arrival on the optical storage scene which we covered in a recent news story. It has a 1TB optical disk in prospect and is looking for a partner/licencee to manufacture and sell drives and disks.

Techworld recently talked to the company's CEO, Wayne Yamamoto, and its engineering VP, Ed Wallace, and found out more about a technology that could radically affect InPhase's holographic storage and Plasmon's UDO.

Call/Recall was founded in 1988 to provide optical storage research consultancy services to the US government. It received its first government contract in 1989 and has, in total, received 14-15 such contracts involving $20 million of funding. During its life it has filed numerous patents for widely-used intellectual property. For example:-

- Patent number 5,325,324, dealing with Three Dimensional Optical Memory, is cited by 42 patents from companies such as Lucent, Nikon, IBM, Xerox and NEC.
- Patent number 5,268,862, also covering Three Dimensional Optical Memory, is cited by 44 other patents.

The three-dimensional optical storage technology promises very high capacity on standard CD/DVD-sized disks of 120mm diameter. It successfully recorded 300GB of data on a 102mm diameter disk and has now achieved 1TB on a 120mm platter.

In 2005, there was an injection of outside capital and Wayne Yamamoto became its CEO. Since then the focus has been on commercialising its technology. What do we know about this technology?

Flourescing dyes

The Call/Recall website has a Technology button which goes through aspects of the technology via some PowerPoint-type slides that are quite hard to read. The writing and reading of data is achieved by lasers. A polymer host layer has a dye precursor and an acid generator on it. The acid generator is excited by laser light and reacts with the dye precursor to produce a Rhodamine-type dye. This dye flouresces (gives off light) when excited by a laser. That is, it absorbs energy at a specific wavelength and emits it at another, specific wavelength - which means it can be detected and thus a binary one or zero read from that spot on the disk's surface.

This process is not reversible and so it produces write-once-read-many (WORM) disks. Call/Recall says it is working on re-writable media as well.

What makes Call/Recall's technology more interesting is that it is multi-layer. In fact the company is taking about the equivalent of 250 DVD layers. Obviously it has to have a reading/writing lens capability to focus its laser light at the precise layer and it does this with fluid-filled lenses. By adding or removing fluid the lens' profile is changed and thus its focal point. In the 300GB demonstration there were 300 layers and the disk was 4.5mm thick. A normal CD is about 1mm thick.

Call/Recall is now talking about shrinking the recording area size, developing its lens technology further and so establishing a 1TB disk, then in phase 2, a 5- to 10-TB disk, and eventually reaching 15TB on a DVD-diameter platter. That would involve a move to blue laser technology.

What makes Call/Recall's technology even more interesting is that it is talking about 100MB/sec I/O rates, five times faster than InPhase's holographic disk. It thinks it can raise this to 500MB/sec.

Another potential benefit of its technology is that, apart from its platter recording layer chemistry and lens technology, its drives use pretty standard components such that drive pricing in the near-DVD area should be achievable. InPhase's holo drives are looking to cost $12,000 to $15,000 dollars.

Then, also, the drives could be made compatible with CD, DVD and Blu-Ray technology to provide backwards compatibility. That is something that is just not feasible with holographic storage from InPhase, and nor has Plasmon mentioned supporting Blu-Ray in its UDO drives.

The market

What markets would need a storage technology storing data for 50 years or more, costing at near-tape levels in terms data stored, backwards-compatibility to DVD and Blu-Ray plus a reasonably fast read/write speed? The obvious market is the archival storage of data by enterprises, specifically media companies storing digital media, health organisations storing medical images, life sciences and oil and gas companies storing their rich data, and then the generality of enterprises storing regulatory and compliance data.

It's the market UDO is successfully being used for presently. InPhase's products are being aimed at digital media companies. Tape is the archive media of choice for the generality of enterprise archive needs.


Call/Recall is now talking to potential licensees who might use its technology to manufacture drives and/or media. The company is not looking to organise production and distribution itself. What it needs is or are businesses with product facilities and access to distribution channels that can deliver product to end-users. The sorts of companies might be Imation or Hitachi-Maxell for media. It is talking to potential licensees at a non-disclosure level and asserts that, were productisation to begin now then, products could perhaps be available in 2009.

It is not time for InPhase or Plasmon to be worried. But if productisation licensees are found then the Call/Recall blip on their competition-watching radar screen will get a lot brighter, depending of course on the track record and credibility of the licensee.

For now, with no product actually produced, neither drive nor media, then this is a technology company to watch. Its track record in developing useful optical storage IP is a good one - remind yourself of its patent history above - and the technology is very promising. Watch this space to see what happens next.