IBM announced last week two high-end versions of its eServer zSeries z990 mainframe computer.The z990, codenamed T-Rex, previously came in two models: the eight-processor Model A and the 16-processor Model B. The two new versions are the 24-processor Model C and 32-processor Model D. The Model D provides over 9,000 MIPS of processing capability.With the two new mainframes, IBM has also improved its On\/Off Capacity on Demand feature, in which customers pay only for the processing power they use. Previously, this feature only worked with the IBM z\/OS operating system, but it now works with mainframes running Linux. IBM has also added Fibre Channel capability to the Linux partitions of the z990, so they can attach to Fibre Channel storage-area networks.Further, IBM announced that a cryptographic coprocessor has been added to the z990, thus speeding encrypted communications. And the company can now use its Parallel Sysplex technology to connect mainframes located as much as 62 miles apart for disaster recovery purposes.IBM will offer discounts of as much as $250,000 if z990 customers buy IBM\u2019s WebSphere software, its BladeCenter blade servers and its grid software, which allows compute resources to be shared across a geographic landscape.IBM launched the zSeries 990 in May. It uses 64-bit G8 processors, which operate at 1.2 GHz. Each processor provides as much as 485 MIPS.The z990 starts at $1 million.