AMP(Access Module Processor)

It is the Virtual Processor (vproc) used to manage the database handle file tasks and and manipulate the disk subsystem in the multi-tasking and possibly parallel-processing environment of the Teradata Database.Each AMP attached to the Teradata system listens to the PE via the BYNET for instructions. Each AMP is connected to its own disk and has the privilege to read or write the data to its disk. The AMP can be best considered as the computer processor with its own disk attached to it. Whenever it receives the instructions from the PE it fetches the data from its disk and sends it to back to PE through BYNET. Each AMP is allowed to read and write in its own disk ONLY. This is known as the SHARED NOTHING ARCHITECTURE.Teradata spreads the rows of the table evenly across all the AMPs, when PE asks for data all AMPs work simultaneously and read the records from its own DISK. Hence a query will be as slow as the slowest AMP in the system. This is known as parallelism.

Each AMP then contained its own microprocessor, disk drive, file system, database software (Database Manager), Teradata Operating System (TOS), and YNET interface. There may be multiple AMPs on one node, and the communication among the AMPs is controlled by the BYNET. 

Function
The functions of AMP can be classified as the following:
   1. BYNET interface, or Boardless BYNET interface;
   2. Database management:
         1. Locking;
         2. Joining;
         3. Sorting;
         4. Aggregation;
         5. Output data conversion;
         6. Disk space management;
         7. Accounting;
         8. Journaling;
   3. File-subsystem management;
   4. Disk-subsystem management.