Drive Status Bytes Found in BIOS Data Area

		Drive recalibration status (at 40:3E)

		|7|6|5|4|3|2|1|0| byte at 40:3E
		 | | | | | | | `--- 1=recalibrate drive 0
		 | | | | | | `---- 1=recalibrate drive 1
		 | | | | | `----- 1=recalibrate drive 2
		 | | | | `------ 1=recalibrate drive 3
		 | `----------- unused
		 `------------ 1=working interrupt flag

		Diskette motor status

		|7|6|5|4|3|2|1|0| byte at 40:3F
		 | | | | | | | `--- 1=drive 0 motor on
		 | | | | | | `---- 1=drive 1 motor on
		 | | | | | `----- 1=drive 2 motor on
		 | | | | `------ 1=drive 3 motor on
		 | `----------- unused
		 `------------ 1=write operation

		Disk Status Byte

		|7|6|5|4|3|2|1|0| byte at 40:41
		 | | | | | | | `--- invalid diskette command
		 | | | | | | `---- diskette address mark not found
		 | | | | | `----- sector not found
		 | | | | `------ diskette DMA error
		 | | | `------- CRC check / data error
		 | | `-------- diskette controller failure
		 | `--------- seek to track failed
		 `---------- diskette time-out

		Last diskette data rate selected

		|7|6|5|4|3|2|1|0| byte at 40:8B
		 | | | | `--------- step rate time selected (see below)
		 `---------------- data rate selected (see below)

		Bits
		 76  Diskette Data Rate Selected
		 00  500K bps
		 01  300K bps
		 10  250K bps
		 11  reserved

		Bits
		 54  Diskette Step Rate Time Selected
		 00  step rate time of 0C
		 01  step rate time of 0D
		 10  step rate time of 0A
		 11  reserved

		Media state for fixed drives (bytes at 40:90-93)

		|7|6|5|4|3|2|1|0| bytes at 40:90-40:93
		 | | | | | `------- reserved (set to 1)
		 | | | | `-------- reserved
		 | | | `--------- 0=media/drive unestablished
		 | | `---------- reserved
		 `------------- data rate (see below)

		Bits
		 76  Fixed Disk Data Rate Selected
		 00  500K bps
		 01  reserved
		 10  250K bps
		 11  reserved

	- not all OEM's implemented these bytes identically.  Some are
	  also AT specific.