Each year Shimano prepares the specifications of the parts they will make available to factories that build complete bikes. These specifications are put together in the form of tables, and sent individuals who design bikes and specify the components that will go on them. This information is prepared in February and sent to them in March. It contains information for the next years parts, so in March they received information on the Shimano line of parts.
Here are the tables of the 1998 Shimano line of parts....
Bottom Bracket Specifications
MTB Brake Specifications
Road Brake Specifications
MTB Brake Lever Specifications
MTB Cassette Cog Sets Specifications
Road Cassette Cog Sets Specifications