Step 3
The compiler compiles the info on the first variable. It says, "The variable ID, a numeric variable, will be read off the first two bytes."

DATA POINTER;  
   INPUT @1  ID       3.  
         @5  GENDER  $1.  
         @7  AGE      2.  
         @10 HEIGHT   2.  
         @13 DOB      MMDDYY6.;  
FORMAT DOB MMDDYY8.;  
DATALINES;

Results
The Program Data Vector (PDV):

variable	characteristics
_N_	numeric
_ERROR_	numeric
ID	numeric

The input buffer

On disk:
(nothing).