There's one bit reserved per NULL column per record. With 9 NULL columns you get 9 bits or two bytes.

>

>CREATE CURSOR temp ( ;
>  c1 C(1) NULL ,;
>  c2 C(1) NULL ,;
>  c3 C(1) NULL ,;
>  c4 c(1) NULL ,;
>  c5 C(1) NULL ,;
>  c6 C(1) NULL ,;
>  c7 c(1) NULL ,;
>  c8 c(1) NULL  ;
>)
>LIST stru
>

>
>Total record length is 10 bytes (1 for delete, 1 for NULL)
>
>

>CREATE CURSOR temp2 ( ;
>  c1 C(1) NULL ,;
>  c2 C(1) NULL ,;
>  c3 C(1) NULL ,;
>  c4 c(1) NULL ,;
>  c5 C(1) NULL ,;
>  c6 C(1) NULL ,;
>  c7 c(1) NULL ,;
>  c8 c(1) NULL ,;
>  c9 c(1) NULL ;
>)
>LIST stru	
>

>
>Added just one more column and instead of 11 bytes (9 + 1 for delete + 1 for NULL) it returns 12. Why? What is up with the extra byte?