Status Response To Tdv - Xerox 7240 Reference Manual

Table 5. Status Response ta SIO, TIO, and HIO (cant.)
Bit
Position Function
State Meaning
4
Unusual End
1 Previous controller operation terminated due to one of
the conditions listed under "Unusual End Conditions".
5,6
Controller Condition
A combination of these two bits indicates the current
controller condition:
00 Controller "ready".
0 1 Not applicable.
1 0 Not applicable.
l l Control
I
er "busy".
7
Unassigned
0 Currently unassigned and always zero.
Table 6. Status Response to TDV
Bit
Position
Function State Meaning
0
Data Overrunt 1
Data overrun (rate error) has occurred during execution
of the previous order.
1
Flaw Markt 1
A flaw mark has been detected while reading header.
2
Sector Unavailablet 1
A nonexistent data address was used in the previous
Seek order, or the data address was incremented to a
nonexistent value and a Read, Write, Header Read, or
Header Write was attempted.
3
Unassigned 0 Currently unassigned and always zero.
4
Header Verification Error
t
1
Header verification error (noncomparison) was detected.
5
On Cylinder
tt
1
Positioning is completed (head is on cylinder).
6
Seek Timeout Error
tt
1
Seek timeout error was detected.
7
Header Parity Error
t
1 Header parity error was detected.
tPertains to current or most recent controller operation.
ttRelated specifically to that device addressed by TDV instruction.
12 Status Response