Toshiba T2000 Maintenance Manual page 88

The contents of the HDC status register are described in Tables 3-4 and 3-5.
Bit Name
7 BBK
(Bad block mark)
6 UNC
(Uncorrectable)
5
4 IDNF
(Identification)
3
2 ABRT
(Abort)
1 TK0
(Track 0)
0
3-36
Description
"0"--Otherwise.
"1"--A bad block mark is detected.
"0"--There is no uncorrectable data error.
"1"--Uncorrectable data error has been detected.
Not used.
"0"--Otherwise.
"1"--There was no ID field in the requested sector.
Not used.
"0"--Otherwise.
"1"--Illegal command error or a drive status error occurs.
"0"--The hard disk has found track 0 during a recalibrate
command.
"1"--The hard disk could not find track 0 during a
recalibrate command.
Not used.