Interrupt 41h   Hard Disk Parameters  (XT,AT,XT2,XT286,PS except ESDI disks) 
		Pointer to first Hard Disk Parameter Block, normally located  
		in the controller card's ROM. This table may be copied to RAM 
		and changed, and this pointer revectored to the new table. 
note 1) format of parameter table is: 
	dw      cylinders 
	db      heads 
	dw      starting reduced write current cylinder (XT only, 0 for others) 
	db      maximum ECC burst length 
	db      control byte 
		  bits 0-2 drive option (XT only, 0 for others) 
		  bit 3    set if more than 8 heads 
		  bit 4    always 0 
		  bit 5    set if manufacturer's defect map on max cylinder+1 
		  bit 6    disable ECC retries 
		  bit 7    disable access retries 
	db      standard timeout (XT only, 0 for others) 
	db      formatting timeout (XT only, 0 for others) 
	db      timeout for checking drive (XT only, 0 for others) 
	dw      landing zone    (AT, PS/2) 
	db      sectors/track   (AT, PS/2) 
	db      0 
     2) normally vectored to ROM table when system is initialized. 

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