DEFB	+38,end-calc	and the channel code.
		CALL	171E,STR-DATA	Fetch the data for the stream.
		LD	A,B	Jump forward if both bytes of
		OR	C	the data are zero, i.e. the
		JR	Z,1756,OPEN-1	stream was in a closed state.
		EX	DE,HL	Save DE.
		LD	HL,(CHANS)	Fetch CHANS - the base
		ADD	HL,BC	address of the channel
		INC	HL	information and find the
		INC	HL	code of the channel
		INC	HL	associated with the stream
		LD	A,(HL)	being OPENed.
		EX	DE,HL	Return DE.
		CP	+4B	The code fetched from the
		JR	Z,1756,OPEN-1	channel information area
		CP	+53	must be 'K', 'S' or 'P';
		JR	Z,1756,OPEN-1	give an error if it is not.
		CP	+50	
		JR	NZ,1725,REPORT-O	
1756	OPEN-1	CALL	175D,OPEN-2	Collect the appropriate data
				in DE.
		LD	(HL),E	Enter the data into the
		INC	HL	two bytes in the stream
		LD	(HL),D	information area.
		RET		Finally return.

THE 'OPEN-2' SUBROUTINE
The appropriate stream data bytes for the channel that is associated with the stream being OPENed are found.

175D	OPEN-2	PUSH	HL	Save HL
		CALL	2BF1,STK-FETCH	Fetch the parameters of the
				channel code.
		LD	A,B	Give an error if the
		OR	C	expression supplied is a null
		JR	NZ,1767,OPEN-3	expression; i.e. OPEN #5,"".

Report F - Invalid file name

1765	REPORT-F	RST	0008,ERROR-1	Call the error handling
		DEFB	+0E	routine.

Continue if no error occurred.

1767	OPEN-3	PUSH	BC	The length of the expression
				is saved.
		LD	A,(DE)	Fetch the first character.
		AND	+DF	Convert lower case codes to
				upper case ones.
		LD	C,A	Move code to the C register.
		LD	HL,+177A	The base address of the
				'OPEN stream look-up' table.
		CALL	16DC,INDEXER	Index into this table and locate
				the required offset.
		JR	NC,1765,REPORT-F	Jump back if not found.
		LD	C,(HL)	Pass the offset to the BC
		LD	B,+00	register pair.
		ADD	HL,BC	Make HL point to the start of
				the appropriate subroutine.
		POP	BC	Fetch the length of the
		JP	(HL)	expression before jumping to
				the subroutine.

THE 'OPEN STREAM LOOK-UP' TABLE
177A		DEFB	4B 06	- channel 'K', offset +06, address 1781