short sessRefnum; 2 28 Offset to session refnum

char aspTimeout; 1 30 Timeout for ATP

char aspRetry; 1 31 Retry count for ATP

short cbSize; 2 32 Command block size

Ptr cbPtr; 4 34 Command block pointer

short rbSize; 2 38 Reply buffer size

Ptr rbPtr; 4 40 Reply buffer pointer

short wdSize; 2 44 Write data size

Ptr wdPtr; 4 46 Write data pointer

char ccbStart[296]; 296 50 CCB memory allocated for driver

afpWrite max size(CCB)=296 all

other calls=150