It is no secret that most CD-ROM titles for sale today involve databases, text files or computer software, not rich data types such as video or sound. The International Standards Organization’s ISO 9660 standard, which specifies a format for organizing files and directories on CD-ROM discs for computer access, is almost universally used for these titles.

As a disc format, 9660 can accommodate any files that the operating system (usually MS-DOS) and relevant applications can cope with, including graphics, animation and audio, given the throughput limitations of CD-ROM. It is the interleaving of audio with screen data that requires going beyond 9660 into CD-ROM XA, Multimedia PC or some other format that maintains compatibility with MS-DOS.

While efforts are under way to extend and transcend 9660, a number of standards initiatives that don’t require ISO 9660 changes or extensions were discussed at CD-ROM Expo.

NO STANDARD INTERFACE

The most irritating problem for users of text- and data-oriented CD-ROM titles seems to be the lack of a standard user interface. A librarian, for example, may need to master a dozen or more different retrieval shells — and this number is growing. Because many vendors also supply parts documentation or software manuals on CD-ROM, users might have to learn a number of different user interfaces, with different terminology and menus, as well.

There is, in fact, some progress toward a solution of this problem.

A “client-server” model. Two federal government groups — the Consistent Interface Committee and the Committee on Index Architecture Standards — are each trying to standardize some aspects of the user interface and how data and index information are written to the disc for certain data types.

Despite these efforts, the most widely accepted solution to the problem of inconsistent user interfaces is to adopt a client-server model. This approach separates the application software “client,” which includes the user interface, from the retrieval engine “server” software that actually searches the database.

Once the user shell is separated from the retrieval engine, the idea is to standardize the protocols used to send requests to the server and return them to the client. In this way, a user’s favorite retrieval shell can be employed to query many different databases, created by different data preparation software packages and using different retrieval engines. There are two proposals for standardizing CD-ROM client/server protocols: SFQL, which comes from the airline and aircraft manufacturing industries, and CD-RDX, which was created by the U.S. intelligence community.

The National Information Standards Organization (NISO), part of the American National Standards Institute (ANSI), is evaluating both CD-RDX and SFQL as potential candidates for a client-server standard.

While this activity is under way, CD-ROM data preparation and retrieval software vendors –most notably the large Massachusetts-based CD-ROM publisher Silver Platter — are beginning to decouple their user shells from their retrieval engines, along the lines of the client-server model. Until there are standard client-server protocols, this does not entirely solve the user interface problem, since the mix-and-match flexibility is not automatic.

Yet another NISO committee is working on making it possible to find out more about what a CD-ROM contains without loading a program contained on the disc. An ANSI standard that is likely to emerge would explicitly define a number of existing ISO 9660 fields as holding information about the disc’s “intellectual content,” such as title, abstract, producer, copyright status, data preparer and other credits. In addition, it is expected that each CD-ROM would contain a bibliographic machine-readable catalog record describing the disc, which would be valuable for automatic library cataloguing.

Bernard Banet