Storage Technology Corp yesterday blew virtually its last shred of credibility on its Iceberg disk array for IBM Corp mainframes by saying that beta testing of the product will extend into the second half of 1993, so that it expects limited revenue contribution from the product for next year – it had been looking for some revenue from it this year. The shares promptly nosedived again, falling $8.375 to $23.375. With IBM itself also not able to ship before 1994 at the earliest, the announcement leaves the field clear for EMC Corp with its Symmetrix arrays, and EMC is promising to announce a new product in the line this week. Trying to explain away the devastating news, the Louisville, Colorado company said that the complexity of integrating the software and hardware of the Iceberg subsystem is causing delays. It also said its recent experience with its other disk array product, the mid-range Alpine, has led it to conclude that debugging Iceberg could take longer than expected. Storage Technology said the Alpine fault-tolerant disk array for the AS/400 market, is still on schedule to begin production shipments this quarter.