SAS Certification Prep Guide, 4th Edition

Compilation Phase

Input Buffer

The input buffer is a logical area in memory into which SAS reads each record of a raw data file when SAS executes an INPUT statement. The buffer is created only when the DATA step reads raw data. When the DATA step reads a SAS data set, SAS reads the data directly into the PDV.

Program Data Vector (PDV)

After the input buffer is created, the PDV is created. The PDV is a logical area in memory where SAS builds a data set, one observation at a time. When a program executes, SAS reads data values from the input buffer or creates them by executing SAS language statements. The data values are assigned to the appropriate variables in the program data vector. From here, SAS writes the values to a SAS data set ...