The z990, also known by its code name T-Rex, is a 64-bit mainframe computer from IBM that contains up to 32 processors, together capable of executing approximately 9,000 million instructions per second (MIPS), nearly three times the processing power of IBM's z900. IBM says that the z990 enhances the e-business capabilities of the z900 and that it was designed from the ground up to serve customers' varying on-demand computing needs. The z990 is not only faster but comes with four times as much memory and twice as many I/O channels as the z900.
To serve varying "on demand" situations, the z990 directs processor resources to the highest priority tasks and also minimizes problems that occur when addressable memory becomes insufficient. It also allows dynamic flexible partitioning and resource management under mixed or unpredictable workloads. The z990 supports up to 30 logical partitions. High-speed interconnects make it possible for Internet traffic to move between partitions and virtual servers at memory speed. IBM says that a 16-way z990 system can handle 11,000 Secure Socket Layer (SSL) transactions per second. New versions of IBM's z/OS and its DB2 database product help support these capabilities.
The basic hardware unit in a z990 is the Multichip Module (MCM), which IBM says is "the world's densest logic package with over three billion transistors." An MCM comes as a unit with memory cards holding up to 64 gigabytes (GB) and Self-Timed Interconnects; each of these units is known as a book. A z990 can include up to four books. The z990 allows the installation of up to 512 local communication channels across three I/O cages. (A cage is a structure into which channel connections can be installed.)