INT 19 - Bootstrap Loader

	DL = physical drive where boot sector is located

	no output

	- track 0, sector 1 is loaded into address 0:7C00
	  and control is transferred there
	- not a preferred method for rebooting by applications.  A
	  better method is to set the word at location 40:72 to 1234h
	  and jump to location FFFF:0 in ROM
	- memory is not cleared when rebooted through this interrupt

	- see	WARM BOOT