Optical Options Expand

Optical Options Expand

A quick review of optical disc technologies and market forces, including emerging formats such as the controversial DVD.

Mike Dudick

WWhen PCs were first introduced with 5MB hard drives, users wondered how they would ever fill them. Today, 1GB drives are mandatory.

Initially, network server capacities were in the 1GB range. Now, 20GB capacities are entry level.

With organizations implementing more image-enriched documents and multimedia applications, storage requirements are taking on new dimensions. Strategic Research, a market research firm in Santa Barbara, CA, estimates that storage requirements in stand-alone and networked environments are growing at more than 50% a year.

Some of the factors driving the storage explosion include data warehouses (often compounded by replication across multiple sites), multimedia (a single minute of compressed video requires up to 12MB), the Web, and business process re-engineering.

Historically, storage represented 25% of the cost of a server. Today, it`s almost 40%. And in some server environments, storage costs may even exceed server costs.

By developing a comprehensive storage blueprint that addresses the issues of cost, availability, performance, scalability, and total cost of ownership (including management), IT managers can determine the best solution for each application.

Users often fail to project the growth in storage requirements as they continue to add new applications. While throughput is a key factor in the performance of any application, other factors--such as how frequently the data will be accessed and total cost of ownership--must be part of the evaluation process.

The demand for 7x24 access to information has forced some organizations to evaluate storage solutions that, from a price/performance standpoint, fall between high-speed hard drives and low-cost tape. The objective is to use the most cost-effective approach for each application, without sacrificing performance.

To meet the demand, optical storage has evolved into a broad range of technologies. While optical technology cannot match the performance of hard drives, not every application requires that level of throughput. In some cases, users can realize significant savings by moving less active files to lower-cost removable optical storage.

Optical discs offer high capacity, durability, and longevity. (The media has a data life of more than 40 years.) Optical media is virtually impervious to contamination or data corruption due to magnetism, moisture, or other contaminants that frequently damage magnetic media. And optical discs are more durable than magnetic media or tape--an important factor when transporting discs for off-site storage or when working in harsh environments. In addition, unlike tape, which records information sequentially, optical discs provide relatively fast random access to data.

These features have increased optical`s popularity in such data-intensive applications as multimedia, graphic design, digital audio and video editing, and network and database storage and archiving.

While three basic optical recording technologies are available today, the product classes are generally divided into two broad categories: CD-based (which includes DVD) and MO.


CD-ROM, used primarily for distributing applications and data, has become a standard for new PC systems. According to Disk/Trend, a market research firm in Mountain View, CA, CD-ROM drive sales exceeded 66 million units last year. This year, shipments could reach 78 million units (including DVD-ROM drives). To expand the use of CD technology, manufacturers have introduced CD-Recordable (CD-R) and, more recently, CD-ReWritable (CD-RW) drives.

Because CD-R drive prices are now below $400, and removable 650MB media is less than $2 per disc, CD-R discs are increasingly being used to distribute limited quantities of databases (1 to 200 copies), which isn`t cost-effective for mass production on CD-ROMs.

With the introduction of multifunction CD-RW drives, the life cycle of record-only drives appears to be short. The new CD-RW drives can write to both CD-R and CD-RW discs and can read CD-ROMs. More versatile than CD-R drives, CD-RW drives give users the flexibility to meet temporary and permanent storage requirements with a single system.

CD-RW media can be used to store large files such as presentations, Web downloads, and multimedia applications or to produce limited copies of stable files and databases. For backup and archiving applications or for storing files that won`t be changed, CD-R media, which has a storage cost of less than one cent per MB, can be more cost-effective.

Recorded CD-RW media can be read in any CD drive that conforms to the MultiRead specification, which was implemented by most CD-ROM manufacturers last year, making it an ideal medium for file distribution and disaster recovery. (For more information about the MultiRead specification, see InfoStor, March, p. 42). Because of standards issues in the DVD market, analysts predict strong CD-RW drive sales until 2000, when DVD will gain widespread acceptance.

In fact, the DVD rewritable battle has given CD-RW sales a boost. Both DVD camps have committed to providing backward compatibility with CD-R and CD-RW media. Since there is uncertainty as to which DVD format to implement, many users have elected to stay with CD-RW until the situation is resolved.

DVD Stalled

DVD technology was initially developed as a high-capacity content carrier for data and video. This new storage medium is targeted at high-volume storage applications, including movies, application programs, and audio data storage. Rewritable DVD has been announced in two formats: DVD+RW and DVD-RAM.

DVD+RW provides 3GB per side; DVD-RAM, 2.6GB per side. Wolfgang Schlichting, an analyst with IDC, says the DVD format competition, combined with the lack of a DVD-ROM installed base and compelling content, will help CD-RW sales and applications remain strong through the year 2001.

Schlichting predicts 1998 will be a high noise level year for DVD+RW and DVD-RAM, but 650MB CD-RW drives (which support both CD-R and CD-RW media) will dominate optical shipments for the next two years. After that, Schlichting and other analysts predict shipments of DVD-based drives to surpass CD shipments.


Multifunction MO drives are available in two form factors: 3.5-inch and 5.25-inch. The smaller form factor drives come in two capacities--230MB and 640MB. The 640MB media is backward read/write-compatible with 230MB drives. Most 5.25-inch MO manufacturers have recently introduced 8X drives and media that provide a storage capacity of 5.2GB per disc. The 5.25-inch drives are also backward compatible for two generations (1.3GB and 2.6GB).

With the exception of Japan, 3.5-inch MO applications are slowly disappearing as CD-R and CD-RW products become more widely used for sub-1GB applications such as Web authoring, creative, and engineering design applications.

5.25-inch MO drives are typically used in applications such as audio and video, as well as prepress production where removability, data integrity, performance, and the use of highly stable media are overriding requirements.

With a storage cost of less than four cents per MB, a data life of 40+ years, and access speeds of less than 24msec, MO is predominantly used in health-care, insurance, banking/finance, and government industries. Stand-alone drives are often used to provide high-speed access to volumes of current information (less than 30 days old). When the individual disc is full and the data becomes less active, the discs are migrated to high-capacity jukeboxes.

Towers, Jukeboxes

Because of the growing demand for high-capacity, low-cost server-based storage as well as centralized data marts and data warehouses, sales of optical drive (CD and MO) towers and jukeboxes are expected to increase by an average of 8% during the next three years, according to Disk/Trend.

Last year, Compaq, Dell, and IBM introduced CD-based server towers, with 8 to 10 drives, for Web and departmental applications. Similar inexpensive towers, which can be easily attached to departmental servers, are becoming increasingly popular. For realtime video applications, highly animated, interactive Web site development, or other applications for which higher capacities and faster response times are critical, some companies are integrating MO jukeboxes.

While the number of library shipments declined last year, Disk/Trend expects shipments to resume a modest growth path over the next few years. Sales will be highest for libraries with 30 to 99 discs (156GB to 515GB with 5.2GB drives). Organizations implementing enterprise-wide data warehouses may require multiple 30- to 99-disc jukeboxes. Up to seven jukeboxes can be daisy chained to provide terabytes of near on-line storage capacity. MO jukeboxes will be preferred because they provide sufficiently fast access (3 to 5 sec) to large databases at a much lower cost than hundreds of hard drives.

Analysts point out that optical technologies have always had to compete with hard-drive performance and that in the end, applications dictate storage solutions. With the applications for optical technology on the upswing, IDC predicts sales of all optical drives will increase from last year`s 59.6 million to more than 110 million by the year 2002.

There is also fierce competition among the various optical technologies. Now that OEM prices for CD-ROM drives are between $60 and $72, they have become commodities. However, low-cost CD-RW drives will continue to drive sales of 650MB CD-based products through the year 2001. Sales of CD-RW drives and media won`t begin to decline until competitively priced DVD-rewritable solutions are widely available.

Optical Recording



5-1/4O (650MB, 1.2GB, 2.6GB, 5.2GB)

3-1/2O (128MB, 230MB, 640MB)

Organic dye:




Source: Verbatim

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Mike Dudick is product marketing manager at Verbatim Corp., in Charlotte, NC.

This article was originally published on April 01, 1998