User guide > Data > Card buffer allocation (binary data)

To summarise the previous sections for binary data, cards are placed in buffers according to the following rules:

If there is no READ command in the CL script, and CARD NUMBERS are specified in a card number column(s), all the cards for a record are read by START DATA, and each card in the record is automatically placed to the appropriate card buffer. Card type 1 is placed in $101-180, card type 2 in $201-280 and so on.

If there is one or more READ commands in the CL script, then cards are read only when READ is executed. A READ command may specify the buffer into which a card is to be read. If no buffer is specified, the card is read into $1-80.

If no CARD NUMBERS are set, and there are no READ commands, START DATA reads one card and places it in $1-80.

The UNLOAD command may be used to move a card from $1-80 to another place which must have been allocated by the CARD NUMBERS command.

If CARD NUMBERS are set, reference to $1-80 is flagged with a warning message at compilation time, see format WBZ (Warning for Buffer Zero).