VIRTUAL PROCESSORS

The versatility of the Teradata RDBMS is based on virtual processors (vprocs) that eliminate dependency on specialized physical processors.  These vprocs are a set of software processes that run on a node under the Teradata Parallel Database Extensions (PDE) and the multitasking environment of the operating system.

The maximum number of vprocs that can be supported in a single system is 16,384.  The maximum number of vprocs per node can be as high as 128.

Each vproc is a separate, independent copy of the processor software, isolated from other vprocs, but sharing some of the physical resources of the node, such as memory and CPUs.  Multiple vprocs can run on an SMP platform or a node.

The vprocs and the tasks running under them communicate using unique-address messaging, as if they were physically isolated from each other.  This message communication is done using the BYNET hardware and driver software.

Vprocs include PEs and AMPs.

For fault protection, vprocs can migrate to a different node in the clique in case of node failure.  My understanding is that our Teradata system has 2 nodes per clique.