CODESG SEGMENT
 	ASSUME CS:CODESG
 	ORG 100H
MAIN: 	JMP SHORT LOAD
OLDINT8 DD ?
COUNT 	DW 275		;275 x 54.94 ms =15 seconds
;---------------- this portion remains resident
NEWINT8 PROC 
 	DEC 	CS:COUNT 	;is the time up? 
 	JNZ 	EXIT
 	MOV 	CS:COUNT,275	;if yes initialize the count
 	MOV 	AH,0EH 	;and 
 	MOV 	AL,7 	;beep the speaker
 	INT 	10H 	;
 	MOV 	AH,0EH 	;do it again
 	MOV 	AL,7
 	INT 	10H
EXIT: 	JMP 	CS:OLDINT8	;take care of INT 08
NEWINT8	ENDP 		
;----------------- this portion is run once only
 	ASSUME CS:CODESG,DS:CODESG
LOAD 	PROC NEAR
 	MOV 	AH,35H 		;get the current CS:IP
 	MOV 	AL,08H 		;for INT 08
 	INT 	21H
 	MOV 	WORD PTR OLDINT8,BX ;save them
 	MOV 	WORD PTR OLDINT8+2,ES
 	MOV 	AH,25H 		;set CS:IP
 	MOV 	AL,08H 		;for the new INT 08
 	MOV 	DX,OFFSET NEWINT8	;DX=offset IP, DS=CS set by COM
 	INT 	21H
 	MOV 	DX,(OFFSET LOAD-OFFSET CODESG) ;find how many bytes resident 
 	ADD 	DX,15 		;round it 
 	MOV 	CL,4 		;to paragraph 
 	SHR 	DX,CL 		;size and 
 	MOV 	AH,31H 		;make it
 	INT 	21H 		;resident
LOAD 	ENDP
CODESG 	ENDS
 	END 	MAIN