Program Data Vector

What is Input Buffer?

Definition: Area of memory created to hold a record from external file. It is created only when raw data is read, not when SAS data set is read. It is created in Compilation phase.

What is Program Data Vector?

Definition: Temporary area of computer memory in which SAS builds a data set, one observation at a time. It is logical concept and short for PDV. 

It is created in Compilation phase after input buffer is created. It contains two automatic variables _N_ and _ERROR_ that can be used for processing but are not written to data set as part of observation.

_N_ counts number of times that data step begins to execute

_ERROR_ signals occurrence of an error that is caused by data during execution. Value of 0 is default which means no error. Value of 1 means one or more errors.

The Compilation phase ends with creation of descriptor portion of data set.