Requirements for IMS 7.1 and HALDB Database Changes

For the past few decades, the IMS database arena has been very quiet. The last major enhancements were the addition of VSAM support in the mid-1970s and the introduction of Fast Path databases in the late 1970s. OSAM was enlarged to allow a 4 GB size limit in the 1980s and again to 8 GB in the 1990s.

The new century starts with a big bang. IMS 7.1 introduces high availability large databases (HALDB), and the analogy to a computer in a famous Arthur C. Clark novel is probably purely accidental. When I was confronted with HALDB for the first time, I considered spelling it "HELLDB" because of the amount of work that this would create.

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